Using Stored Procedures with Linq To Sql which have Additional Parameters - asp.net-mvc

I have a very big problem and can't seem to find anybody else on the internet that has my problem. I sure hope StackOverflow can help me...
I am writing an ASP.NET MVC application and I'm using the Repository concept with Linq To Sql as my data store. Everything is working great in regards to selecting rows from views. And trapping very basic business rule constraints. However, I'm faced with a problem in my stored procedure mappings for deletes, inserts, and updates. Let me explain:
Our DBA has put a lot of work into putting the business logic into all of our stored procedures so that I don't have to worry about it on my end. Sure, I do basic validation, but he manages data integrity and conflicting date constraints, etc... The problem that I'm faced with is that all of the stored procedures (and I mean all) have 5 additional parameters (6 for inserts) that provide information back to me. The idea is that when something breaks, I can prompt the user with the appropriate information from our database.
For example:
sp_AddCategory(
#userID INT,
#categoryName NVARCHAR(100),
#isActive BIT,
#errNumber INT OUTPUT,
#errMessage NVARCHAR(1000) OUTPUT,
#errDetailLogID INT OUTPUT,
#sqlErrNumber INT OUTPUT,
#sqlErrMessage NVARCHAR(1000) OUTPUT,
#newRowID INT OUTPUT)
From the above stored procedure, the first 3 parameters are the only parameters that are used to "Create" the Category record. The remaining parameters are simply used to tell me what happened inside the method. If a business rule is broken inside the stored procedure, he does NOT use the SQL 'RAISEERROR' keyword when business rules are broken. Instead, he provides information about the error back to me using the OUTPUT parameters. He does this for every single stored procedure in our database even the Updates and Deletes. All of the 'Get' calls are done using custom views. They have all been tested and the idea was to make my job easier since I don't have to add the business logic to trap all of the various scenarios to ensure data quality.
As I said, I'm using Linq To Sql, and I'm now faced with a problem. The problem is that my "Category" model object simply has 4 properties on it: CategoryID, CategoryName, UserId, and IsActive. When I opened up the designer to started mapping my properties for the insert, I realized that there is really no (easy) way for me to account for the additional parameters unless I add them to my Model object.
Theoretically what I would LIKE to do is this:
// note: Repository Methods
public void AddCategory(Category category)
{
_dbContext.Categories.InsertOnSubmit(category);
}
public void Save()
{
_dbContext.SubmitChanges();
}
And then from my CategoryController class I would simply do the following:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(FormCollection collection)
{
var category = new Category();
try
{
UpdateModel(category); // simple validation here...
_repository.AddCategory(category);
_repository.Save(); // should get error here!!
return RedirectToAction("Index");
}
catch
{
// manage friendly messages here somehow... (??)
// ...
return View(category);
}
}
What is the best way to manage this using Linq to Sql? I (personally) don't feel that it makes sense to have all of these additional properties added to each model object... For example, the 'Get' should NEVER have errors and I don't want my repository methods to return one type of object for Get calls, but accept another type of object for CUD calls.
Update: My Solution! (Dec. 1, 2009)
Here is what I did to fix my problem. I got rid of my 'Save()' method on all of my repositories. Instead, I added an 'Update()' method to each repository and actually commit the data to the database on each CUD (ie. Create / Update / Delete) call.
I knew that each stored procedure had the same parameters, so I created a class to hold them:
public class MySprocArgs
{
private readonly string _methodName;
public int? Number;
public string Message;
public int? ErrorLogId;
public int? SqlErrorNumber;
public string SqlErrorMessage;
public int? NewRowId;
public MySprocArgs(string methodName)
{
if (string.IsNullOrEmpty(methodName))
throw new ArgumentNullException("methodName");
_methodName = methodName;
}
public string MethodName
{
get { return _methodName; }
}
}
I also created a MySprocException that accepts the MySprocArgs in it's constructor:
public class MySprocException : ApplicationException
{
private readonly MySprocArgs _args;
public MySprocException(MySprocArgs args) : base(args.Message)
{
_args = args;
}
public int? ErrorNumber
{
get { return _args.Number; }
}
public string ErrorMessage
{
get { return _args.Message; }
}
public int? ErrorLogId
{
get { return _args.ErrorLogId; }
}
public int? SqlErrorNumber
{
get { return _args.SqlErrorNumber; }
}
public string SqlErrorMessage
{
get { return _args.SqlErrorMessage; }
}
}
Now here is where it all comes together... Using the example that I started with in my initial inquiry, here is what the 'AddCategory()' method might look like:
public void AddCategory(Category category)
{
var args = new MySprocArgs("AddCategory");
var result = _dbContext.AddWidgetSproc(
category.CreatedByUserId,
category.Name,
category.IsActive,
ref args.Number, // <-- Notice use of 'args'
ref args.Message,
ref args.ErrorLogId,
ref args.SqlErrorNumber,
ref args.SqlErrorMessage,
ref args.NewRowId);
if (result == -1)
throw new MySprocException(args);
}
Now from my controller, I simply do the following:
[HandleError(ExceptionType = typeof(MySprocException), View = "SprocError")]
public class MyController : Controller
{
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(Category category)
{
if (!ModelState.IsValid)
{
// manage friendly messages
return View(category);
}
_repository.AddCategory(category);
return RedirectToAction("Index");
}
}
The trick to managing the new MySprocException is to simply trap it using the HandleError attribute and redirect the user to a page that understands the MySprocException.
I hope this helps somebody. :)

I don't believe you can add the output parameters to any of your LINQ classes because the parameters do not persist in any table in your database.
But you can handle output parameters in LINQ in the following way.
Add the stored procedure(s) you whish to call to your .dbml using the designer.
Call your stored procedure in your code
using (YourDataContext context = new YourDataContext())
{
Nullable<int> errNumber = null;
String errMessage = null;
Nullable<int> errDetailLogID = null;
Nullable<int> sqlErrNumber = null;
String sqlErrMessage = null;
Nullable<int> newRowID = null;
Nullable<int> userID = 23;
Nullable<bool> isActive=true;
context.YourAddStoredProcedure(userID, "New Category", isActive, ref errNumber, ref errMessage, ref errDetailLogID, ref sqlErrNumber, ref sqlErrMessage, ref newRowID);
}

I haven' tried it yet, but you can look at this article, where he talks about stored procedures that return output parameters.
http://weblogs.asp.net/scottgu/archive/2007/08/16/linq-to-sql-part-6-retrieving-data-using-stored-procedures.aspx
Basically drag the stored procedure into your LINQ to SQL designer then it should do the work for you.

The dbContext.SubmitChanges(); will work only for ENTITY FRAMEWORK.I suggest Save,Update and delete will work by using a Single Stored procedure or using 3 different procedure.

Related

Want to save selected (i.e., more than 1) enums as string with NHibernate

I cannot for the life of me get this to work with my existing code, but I am trying to save my enum selections as strings in NHibernate. Basically, I have a UI check box and if the user selects multiple check boxes I want to store those selections. Now, I can get NHibernate to store ONE selection (e.g., from a drop down or radio button list, where the user is limited to one choice only).
This is the jist of what I have for an enum:
public enum IncomeType
{
[Display(Name = "Full-Time Employment")]
FullTime,
[Display(Name = "Part-Time Employment")]
PartTime,
[Display(Name = "Self-Employment")]
SelfEmployed,
[Display(Name = "Rental")]
Rental,
[Display(Name = "Social Security Payments")]
SocialSecurity,
[Display(Name = "Retirement / Pension Payments")]
Retirement,
[Display(Name = "Child Support Payments")]
ChildSupport,
[Display(Name = "Spousal Maintenance")]
Maintenance,
[Display(Name = "Other")]
Other
}
I use a method to "select" whether a checkbox list is shown (if my BulkItemThreshold equals the number of options, a checkbox list is displayed). Here is that method:
public static IEnumerable<SelectListItem> GetItemsFromEnumString<T>
(T selectedValue = default(T)) where T : struct
{
return from name in Enum.GetNames(typeof(T))
let enumValue = Convert.ToString((T)Enum.Parse(typeof(T), name, true))
select new SelectListItem
{
Text = GetEnumDescription(name, typeof(T)),
Value = enumValue,
Selected = enumValue.Equals(selectedValue)
};
}
(Note: some items in there are helpers, but I don't believe they are relevant; also, the selected input is displayed using a template .cshtml file - again, not sure if that's relevant)
Now, I call this thusly:
public class IncomeTypeSelectorAttribute : SelectorAttribute
{
public override IEnumerable<SelectListItem> GetItems()
{
return Selector.GetItemsFromEnumString<IncomeType>();
}
}
And finally, we get to the virtual property (using a proxy) but this is where NHibernate throws a wrench (Note: this was working fine for me before NHibernate, and now I am trying to get many lines of code working with it WITHOUT having to re-do everything; if I re-do everything I will probably triple the code I already have to get it to work):
Property (record):
[IncomeTypeSelector(BulkSelectionThreshold = 9)]
public virtual List<string> IndividualIncomeTypeCheckBox { get; set; }
proxy (part):
public List<string> IndividualIncomeTypeCheckBox
{
get { return Record.IndividualIncomeTypeCheckBox; }
set { Record.IndividualIncomeTypeCheckBox = value; }
}
Again, this is how I was doing things and it was working great before NHibernate. But now I have to use NHibernate. No getting around it.
I am using a service class that it tying the two together in a Create method to save in the DB with NHibernate, and for the above it would ordinarily look like this:
part.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
This would work if it were just one selection.
Well, I've spent a good two (2) months trying to get this to work. It's tough because I have lots of code where the user can make only one selection (such as with a radiobutton list) and it works GREAT - even with NHibernate. Let me give you an example:
public virtual IncomeType? IndividualIncomeTypeCheckBox { get; set; }
If I do the above, it will display a drop down list, and NHibernate will store the ONE allowable option selected by the user in the DB no problem. But more than one option with List<string> does not work.
Now, I have tried everything I could find here or elsewhere and nothing works. Yes, I know it should be IList<IncomeType> or some other variant. But if I use this then NHibernate requires that IncomeType be another table in the DB. This is too much code to write for such a simple thing I believe. We are not talking a many-to-many relation in the sense that this is not a User with Multiple addresses (wherein addresses would have street, city, state, zip, etc.).
I have tried different types of proxy get and set code, but nothing works. I have tried [Flags] and other things working with string only, but to no avail. Those last solutions would "work" but ONLY to save the first item selected out of multiple (i.e., in my scenario, if the user selected "FullTime" and "Rental" as Income Types, then only "FullTime" (string) would be saved or "1" ([Flags]/int), not both items selected.
I have a situation where I re-display the choices using a ReadOnly attribute like this:
[IncomeTypeSelector]
[ReadOnly(true)]
public List<string> IndividualIncomeTypeCheckBoxPost
{
get { return IndividualIncomeTypeCheckBox; }
}
This would display on the UI, but I tried doing something like this with NHibernate and it wouldn't work.
Could anyone please show me, using the above, how I can go about getting NHibernate to store more than one enum in this checkbox list scenario?
UPDATE:
More poking around here and on the web, and I came up with the following (which still does not work).
Property (record):
[IncomeTypeSelector(BulkSelectionThreshold = 9)]
public virtual IList<IncomeTypeRecord> IndividualIncomeTypeCheckBox
{
get { return incomeType; }
set { incomeType= value; }
}
private IList<IncomeTypeRecord> incomeType =
new List<IncomeTypeRecord>();
Proxy (part):
public IList<IncomeTypeRecord> IndividualIncomeTypeCheckBox
{
get { return Record.IndividualIncomeTypeCheckBox; }
set { Record.IndividualIncomeTypeCheckBox= value; }
}
And a change to the enum:
public enum IncomeType : int // removing int & value still gives validate error
{
[Display(Name = "Full-Time Employment")]
FullTime = 1,
[Display(Name = "Part-Time Employment")]
PartTime,
....
}
And I added this class to support IncomeTypeRecord
public class IncomeTypeRecord
{
public virtual int Id { get; set; }
public virtual IncomeType Value { get; set; }
}
HOWEVER, when I get to the UI screen and pick one or more options I get a validation error (value not valid). For example, say I pick FullTime alone, or pick FullTime and Retirement, then the UI will display the following error:
The value 'FullTime' is invalid.
The value 'FullTime,Retirement' is invalid.
(respectively)
Even if I remove the int declaration for the enum and get rid of the value I started with "1", I still get this validation error. I tried messing around with and adding different model binders (which now has me stumped as to whether my original problem still exists and now I have a different problem - but you still get bounty points :) ).
Pulling my hair out. If I could offer more bounty I would. I need a definitive solution. I appreciate any help.
UPDATE
This is what I have so far:
Record:
public virtual string IndividualIncomeTypeCheckBox{ get; set; }
Part:
//If I do IEnumberable<string> my .Select throws a cast error
public IEnumerable<IncomeType> IndividualIncomeTypeCheckBox
{
get
{
return Record
.IndividualIncomeTypeCheckBox
.Split(',')
.Select(r => (IncomeType)Enum.Parse(typeof(IncomeType), r));
}
set { Record.IndividualIncomeTypeCheckBox= value
== null ? null : String.Join(",", value); }
}
Service Class:
public SimplePart CreateSimple(SimplePartRecord record)
{
SimplePart simple = Services.ContentManager.Create<SimplePart>("Simple");
...
//How I would save a FirstName property (example Part / PartRecord below)
//public virtual string FirstName { get; set; } - PartRecord
//public string FirstName - Part
//{
// get { return Record.FirstName ; }
// set { Record.FirstName= value; }
//}
simple.FirstName = record.FristName;
...
//I obviously cannot do the following with the above IncomeType
//Getting cannot convert string to IEnumerable error
//How would I write this:
simple.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
...
}
And this is how it's called in a controller (this persists to DB): (Updating Controller code)
public ActionResult Confirm(string backButton, string nextButton)
{
if (backButton != null)
return RedirectToAction("WrapUp");
else if ((nextButton != null) && ModelState.IsValid)
{
_myService.CreateSimple(myData.SimplePartRecord);
return RedirectToAction("Submitted");
}
else
return View(myData);
}
Updating with additional code (serialization and view model):
"myData" is defined in the controller (using Serialization) as:
private MyViewModel myData;
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var serialized = Request.Form["myData"];
if (serialized != null)
{
myData = (MyViewModel)new MvcSerializer().Deserialize
(serialized, SerializationMode.Signed);
TryUpdateModel(myData);
}
else
myData = (MyViewModel)TempData["myData"] ?? new MyViewModel();
TempData.Keep();
}
protected override void OnResultExecuted(ResultExecutedContext filterContext)
{
if (filterContext.Result is RedirectToRouteResult)
TempData["myData"] = myData;
}
I use Serialization because I set up a multi-step wizard (as seen in the controller action "backButton" "nextButton) on the front-end. I am not using a driver (which can only display Admin or on the front-end but then only on .cshtml files directly under the ~/Views folder (not in a structured folder list like I am using)). No driver = no update view model type code = no mechanism to "create" the data in the DB. If I do not use some "create" type method, the form will submit but all the data will be "NULL".
When you say that the data should be persisted automatically, I am sorry but I do not see how. All the stuff I read or code I review has SOME method of updating the DB with whatever is entered in a form. If I am missing something, my apologies.
"MyViewModel" is pretty straightforward:
[Serializabel]
public class MyViewModel
{
public SimplePartRecord SimplePartRecord { get; set; }
}
And, just in case, here is the relevant portion of the migration (return 1 is a completely separate and unrelated table):
public int UpdateFrom1()
{
SchemaBuilder.CreateTable("SimplePartRecord",
table => table
.ContentPartRecord()
...
.Column("IndividualIncomeTypeCheckBox", DbType.String)
...
);
ContentDefinitionManager.AlterPartDefinition("SimplePart",
part => part
.Attachable(false));
return 2;
}
The error I am getting is
Cannot implicitly convert type 'string' to 'System.Collections.Generic.IEnumerable'"
when I do the following in the "Create" method of my service class:
simple.IndividualIncomeTypeCheckBox = record.IndividualIncomeTypeCheckBox;
One additional thought: I tried using the n-n Relation sample to handle this scenario. Aside from it being a lot of extra code for what I thought should be straightforward and simple, because of the way I am using Serialization I had a lot of object reference errors and could not figure out how to properly code my controller to handle it.
There's a lot of info to wade through here so hopefully I haven't missed the point. It appears to me that the goals are:
The business class has a collection property of IList<IncomeType> without requiring an additional table
The values in that collection should be persisted as a delimited string of the enum names
The best approach is to use a custom user type (an implementation of NHibernate.UserTypes.IUserType) to map the property. Below is a generic IUserType that will map an enum of type T from an IList<T> property to a comma delimited string in the database and back again. There's no easy way to restrict T to an enum but the code will only work with enums.
Mapping a property using the custom type is simple with Fluent NHibernate:
public class Person
{
public Person()
{
IncomeTypes = new List<IncomeType>();
}
public virtual int PersonId { get; protected set; }
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual IList<IncomeType> IncomeTypes { get; protected set; }
}
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Table("Person");
Id(x => x.PersonId).GeneratedBy.Identity();
Map(x => x.FirstName);
Map(x => x.LastName);
Map(x => x.IncomeTypes).CustomType<EnumAsDelimitedStringType<IncomeType>>();
}
}
And here's the code for the user type:
public class EnumAsDelimitedStringType<T> : IUserType
{
public new bool Equals(object x, object y)
{
if (ReferenceEquals(x, y))
{
return true;
}
var xList = x as IList<T>;
var yList = y as IList<T>;
if (xList == null || yList == null)
{
return false;
}
// compare set contents
return xList.OrderBy(xValue => xValue).SequenceEqual(yList.OrderBy(yValue => yValue));
}
public int GetHashCode(object x)
{
return x.GetHashCode();
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
var outValue = NHibernateUtil.AnsiString.NullSafeGet(rs, names[0]) as string;
if (string.IsNullOrEmpty(outValue))
{
return new List<T>();
}
var getValueArray = outValue.Split(new[] {','}, StringSplitOptions.RemoveEmptyEntries);
return Array.ConvertAll(getValueArray, s => (T)Enum.Parse(typeof(T), s)).ToList();
}
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
var inValue = value as IList<T>;
// set to string.Empty if you prefer to store that instead of null when the collection is null or empty
object setValue = null;
if (inValue != null && inValue.Any())
{
var setValueArray = Array.ConvertAll(inValue.ToArray(), v => Enum.GetName(typeof(T), v));
setValue = string.Join(",", setValueArray);
}
NHibernateUtil.AnsiString.NullSafeSet(cmd, setValue, index);
}
public object DeepCopy(object value)
{
return value;
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return cached;
}
public object Disassemble(object value)
{
return value;
}
public SqlType[] SqlTypes
{
get { return new[] {new SqlType(DbType.AnsiString)}; }
}
public Type ReturnedType
{
get { return typeof(IList<T>); }
}
public bool IsMutable
{
get { return false; }
}
}
I think you're on the right track pursuing a [Flags] enum. You may have done this, but just in case -- making an enum flags-worthy is more than adding the attribute. You also have to specify the value for the items in a binary-friendly manner. I've found the easiest way to do this is as follows:
[Flags]
public enum IncomeType : long // you'll need the room with several options
{
FullTime = 1,
PartTime = 1 << 1,
SelfEmployed = 1 << 2
// And so on
}
If you don't do this, then you'll get sequential integer values, which breaks the bitwise comparison that allows you to do multiple values in a single integer.
Your code to create the SelectList looks fine. Your options should construct form values that get posted back with the same name. If you want to use the default modelbinder, that means the associated property on your view model would need to be List<int>. If you're not using a view model (you probably should) you can pull it out of the forms collection.
Once you have this set up, then translating from your view model to your NHibernate entity is simple if a little annoying. You basically have to cycle through the values in the list and |= them onto your NHibernate entity's single enum property.
So let's assume you have a view model like this:
public class MyEditViewModel
{
public string Name { get; set; }
public List<int> IncomeSelections { get; set; }
// You'll probably have this to populate the initial view rendering
public SelectList AllIncomeOptions { get; set; }
}
You'll build your view using your helpers and all that, then build the checkboxes using the SelectList but making sure the input name is IncomeSelections, then when it's posted back you will push the view model data into your NHibernate entity something like this:
var myNHEntity = new NHEntity();
// If you're editing an existing entity, then be sure to reset the enum
// value to 0 before going into the following foreach loop...
foreach (var incomeSelection in viewModel.IncomeSelections)
{
myNHEntity.IncomeSelection |= incomeSelection;
}
There's probably a more clever way to do this, and you might have to cast the int to your enum type, but you'll figure that out (I'd do it for you, but it is Friday and I already have a beer open).
NHibernate should persist it without you having to do anything funky on the NH side.
In summary...
It seems like this is more a problem of how you handle the posted data than the NHibernate side. If you implement something like this, then be sure to use Fiddler or FireBug to inspect the posted values to make sure 1) they're integers and 2) the names are the same so they'll be added to the list.
Good luck!
The problem is simply that it won't be able to map a List without building a full relationship with an intermediate association table. It is way simpler to have the record store the values as a comma-separated string (so your record property is a string, not a list of string) and your part can map back and forth between string and List.
You can find an example of something very close here:
https://bitbucket.org/bleroy/nwazet.commerce/src/d722cbebea525203b22c445905c9f28d2af7db46/Models/ProductAttributesPartRecord.cs?at=default
https://bitbucket.org/bleroy/nwazet.commerce/src/d722cbebea525203b22c445905c9f28d2af7db46/Models/ProductAttributesPart.cs?at=default
It's not using enum values, instead it's a list of ids, but that should give you a good idea about how to make this work fairly simply: parsing enums you already know how to do.
Let me know if you need more details, but I think that's what you needed to get unblocked.

EntityFramework and ont-to-many CRUD operations

I'm really trying hard to put everything on my project to work with the EF, but it's really getting difficult and sometimes it makes me wonder if it's really the smart move (to rely on EF against coding all the ins and outs of the database).
Well, my problem is still related to 1-N creating/editing/deleting functionality (something that should be simple, right?).
Ok, I'm pasting here some simple equivalent of my code.
For the Entities, I got the main class as:
[Table("OLIM_LOTE")]
public class Lote
{
[Key]
[Column("LOTE_ID_LOTE")]
public int? IDLote { get; set; }
[Column("LOTE_TX_OBS")]
public string Obs {get;set;}
[Column("LOTE_TX_DOCUMENTO_EXTRA")]
public string DocumentoExtra { get; set; }
[NotMapped]
public List<DocumentoLote> Documentos { get; set; }
public void LoadLists()
{
OlimpiqueDBContext myDbContext = new OlimpiqueDBContext();
var docs = (from doc in myDbContext.DocumentosLote
where doc.IDLote == this.IDLote
select doc);
this.Documentos = docs.ToList<DocumentoLote>();
}
}
[Notice that i used the nullable int? for Key - otherwise it throws me validation exception asking for a value on creation]
For the child class, i got this:
[Table("OLIM_DOCUMENTO_LOTE")]
public class DocumentoLote
{
[Key]
[Column("DOLO_ID_DOCUMENTO_LOTE")]
public int? IDDocumentoLote { get; set; }
[Column("DOCU_ID_DOCUMENTO")]
[ForeignKey("Documento")]
public int IDDocumento { get; set; }
public virtual Documento Documento { get; set; }
[Column("LOTE_ID_LOTE")]
[ForeignKey("Lote")]
public int IDLote { get; set; }
public virtual Lote Lote { get; set; }
}
[Notice that the child class has a reference back to the owner class, which are the "IDLote" and "Lote" attributes, and the owner class has a list of child class instances - so I got i bi-directional refernce - I assume that this is somehow related to the problems]
I got a Controller and View generated automatically by VS2012 with Read/Write functionality related to the class Lote.
What I did in the View can be described as: I used a Jquery DataTable to manage the child class data (the user can add "N" instances on the DataTable). I substituted the Post Button with a call to a JS method that simply gets all the data from the Form and from the DataTable and wrap it in a JSon object and send it to the controller via Ajax.
The controller method that receives it can be simplified as below:
[HttpPost]
public JsonResult Edit(Lote lote)
{
try
{
if (ModelState.IsValid) //<< HAVING PROBLEMS HERE... DETAILS BELOW
{
if (lote.IDLote.HasValue)
{
//Separete updates/inserts from deletes
List<int?> dbDocs = db.DocumentosLote
.Where(dt => dt.IDLote == lote.IDLote)
.Select(dt => dt.IDDocumentoLote)
.ToList();
List<int?> postedDocs = lote.Documentos
.Select(pt => pt.IDDocumentoLote)
.ToList();
List<int?> deletedDocs = dbDocs
.Except(postedDocs).ToList();
//Perform deletes
foreach (var delDocId in deletedDocs)
{
if (delDocId.HasValue)
{
DocumentoLote delDoc = db.DocumentosLote
.Where(dt => dt.IDLote == lote.IDLote && dt.IDDocumentoLote == delDocId)
.Single();
db.Entry(delDoc).State = EntityState.Deleted;
}
}
//Perform insert and updates
foreach (var doc in lote.Documentos)
{
if (doc.IDDocumentoLote.HasValue)
{
db.Entry(doc).State = EntityState.Modified;
}
else
{
db.Entry(doc).State = EntityState.Added;
doc.IDLote = (int)lote.IDLote;
}
}
}
else
{
db.Lotes.Add(lote);
}
db.SaveChanges();
// If Sucess== 1 then Save/Update Successfull else there it has Exception
return Json(new { Success = 1, ex = "" });
}
else
{
return Json(new { Success = 0, ex = "Falha ao tentar salvar os dados" });
}
}
catch (Exception ex)
{
// If Sucess== 0 then Unable to perform Save/Update Operation and send Exception to View as JSON
return Json(new { Success = 0, ex = ex.Message.ToString() });
}
}
Problems: Well I really passed through a lot to got to this point and now, I got only 2 problems. The first being that the creation is throwing a Validation Exception sayin that it needs an IDLote (for the child classes - but anyway, how would i have it if the owner class itself still doesn't have an Id at that point in creation?)
Second problem: Deletion dont work at all! Doesn't matter how i code it, it throws the exception "objects cannot be defined because they are attached to different ObjectContext objects". I really feel that this has something to do with the bidirectional reference between owner-children classes, but still, don't have a clue on exactly whats happening and how to solve it
I'm starting to feel really lost here. Any ideas on this would be very appreciated. Thanks
As there are a lot of views on this old question and now I do have some answer, I'm posting them for reference:
Q - Regarding the int? type for the key attributes:
A - It doesn't have to be a nullable int at all. The entity can be declared with a simple int attribute as key and when posting the JSon object from the View, back to some controller method, this attribute (the key) can be filled with the value "0". EF will generate the correct value as soon as it persists the object.
Q - Regarding the navigational attributes and how to implement the relation between the two classes when neither of them have already got a value (non-zero) on theis keys:
A - The JSon object to be sent back can implement the exact navigational relationaship between them. Wehn the controller binds the data posted to the model it should be receiving, it will "understand" their relationship and as soon as the values for the keys are generated, they will correctly reference one another.
Q - Regarding the error described on the delete method attempts:
A - When objects should interact with other objects, and those interactions should be persisted or "understood" by EF in any way, they must have been obtained, generated or attached to a same DBContext. EF rely on the DB context to create a tree of this interactions, thus, rendering impossible to build this tree when objets are not present on the same DB Context.

Entity framework add a where clause to all queries

I am using Entity framework 5 and using repository pattern. Say I got these entities Customer, Files, Images, Tasks, Invoice, User.
Each entity (apart from Customer) has a foreign key of Customer. When a user logs in I store the customerid in session (aps.net mvc). What I want is any CRUD taken on all entities to be limited to the customer who's user is logged in. e.g I can't afford to delete a Task belonging to customer 1 to be deleted by user who is from customer 2.
Is adding an argument of customerid for each method of repositories the best way to achieve this or are there any better/clever ways of doing it?
Tricky to give a definitive answer but you could make it a bit more extensible by implementing higer order functions, like this:
public interface IRepository<T>
{
public T GetBy(Expression<Func<T, bool>> query)
}
public class FileRepository : IRepository<File>
{
public File GetBy(Expression<Func<T, bool>> query)
{
using(var context = new FilesContext())
{
return context.Files.Where(query).FirstOrDefault();
}
}
}
public class SomeController
{
private IRepository<File> _repo;
public SomeController(IRepository<File> repo)
{
_repo = repo;
}
public ActionResult Index()
{
var model = _repo.GetBy(f => f.CustomerId == Session.Whatever.CustomerId);
return View(model);
}
}
This way you can vary the search query when required, rather than tie yourself in to using a hardcoded customer id property. For example, if you wanted to get the File object by the FileID, not the CustomerID, then:
var model = _repo.GetBy(f => f.FileId == someId);
and that's the only part of the code that needs to change.
Some really good info on Higher Order functions and functional programming in C# here: http://www.codeproject.com/Articles/375166/Functional-programming-in-Csharp
Edit:
You might be able to isolate the "Always use the customer ID when hitting DB" into a repository of it's own, using a decorator style pattern, thus: (massive disclaimer - I haven't tested this, but something along these lines should work)
public class SpecialFileRepo : IRepository<File>
{
private readonly IRepository<File> _baseRepo;
public SpecialFileRepo(IRepository<File> baseRepo)
{
_baseRepo = baseRepo;
}
public SpecialFileRepo() : this(new FileRepository())
{
}
public File GetBy(Expression<Func<File, bool>> query)
{
var parameters = query.Parameters;
var newParam = Expression.Parameter(typeof (File), "f");
var additionalQuery = Expression.AndAlso(query.Body,
Expression.Equal(
Expression.PropertyOrField(newParam, "CustomerId"),
Expression.Constant(HttpContext.Current.Session["customerId"])));
var newQuery = query.Update(additionalQuery, parameters);
return _baseRepo.GetBy(newQuery);
}
}
Then anything that's talking to a repository, as far as it's concerned, it's just a base repository, but this class is sitting in between and always grafting the "customerid = sessionwhatever" expression onto what finally gets passed to the database. And of course, anything that only cares about using the base repository, can still do so.

In MVC, why does the routeValues property in RedirectToAction() not accept my class as argument?

So here's the deal, i want to be able to export any Enumerable of items to excel:
Here's an ActionMethod in some Area of my app that constructs an "ExportToExcel" model, then Redirects it to an Action Method in another controller and another are which does all the formatting-to-excel work:
public ActionResult ExportCustomListToExcel()
{
var exportModel = new ExportToExcelModel();
//Here I fill up the model with a dataTable / other file info like
//exportModel.Items = blah blah..
return RedirectToAction("ExportToExcel", "Shared", new { model = exportModel, testString = "test", area = "Shared" });
}
And here's my Shared ExportToExcel ActionMethod:
public ActionResult ExportToExcel(ExportToExcelModel model, string testString)
{
//PROBLEM IS RIGHT HERE!
// where testString == "test"
// but model == null :(
//Ommited unrelated code
}
My ExportToExcel actionMethod gets hit, but somewhere along the way my ExportToExcelModel gets lost :(
Note: It succeeds on passing strings like "testString" so is there somwthing wrong with my model?
Just in case, the ExportToExcelModel is:
public class ExportToExcelModel
{
public ExportToExcelModel() {}
public ExportToExcelModel(string fileName, ItemType itemType, IEnumerable<ExportableToExcelItem> items)
{
this.FileName = fileName;
this.ItemType = ItemType;
this.Items = items;
}
public string FileName { get; set; }
public ItemType ItemType { get; set; }
public IEnumerable<ExportableToExcelItem> Items { get; set; }
}
Thanks in advance!
First time i've ever needed to actually ask a question here since every other question i've ever had i've found already answered here :)
EDIT: Posting FormCollection results:
http://imageshack.us/photo/my-images/861/sinttulonsa.png
Sorry, newbies cant post pics :(
The reason is that a RedirectToAction result will launch a GET request and your parameters will have to be passed along through the querystring. Obviously there is a limit to the amount of characters a url can consist of.
Seems to me that you should do the conversion to Excel in a class instead of behind another Action.
So CustomExportAction1 and CustomExportAction2 both call
return File(ExcelExporter.ExportExcel(dataToExport));
or something similar.
try to switch your ExportToExcel signature to
public ActionResult ExportToExcel(FormCollection data)
{
var model = new ExportToExcelModel();
try
{
UpdateModel(model, data)
}
catch(UpdateModelException ex)
{
}
}
look at what's in the FormCollection (that might help), and also see if UpdateModel is throwing an exception, because this is what is happening behind the seen when you make your action method take in a model instead of a FormCollection.
Hope that help you track it down
UPDATE:
You might have to do it using TempData, read this, supposedly you can't do this out of the box with ASP.NET MVC!!

Iterating over an unknown IQueryable's properties?

Forgive me if this has been asked before; I couldn't find anything close after a few searches:
I'm trying to write an ActionFilter in MVC that will "intercept" an IQueryable and nullify all the parent-child relationships at runtime. I'm doing this because Linq does not serialize objects properly if they have parent-child relationships (it throws a circular reference error because the parent refers to the child, which refers back to the parent and so on), and I need the object serialized to Json for an Ajax call. I have tried marking the child relationship in the DBML file with a privacy status of internal, and while this fixes the serialization problem, it also hides the child members from the view engine when the page renders, causing another error to be thrown. So, by fixing one problem, I cause another.
The only thing that fixes both problems is to manually set the child members to null just before returning the serialization, but I'm trying to avoid doing that because it's cumbersome, not reusable, etc. I'd rather use an ActionFilter to inspect the IQueryable that is being serialized and nullify any members with a Type of EntitySet (how Foreign Keys/Associations are represented). However, I don't have much experience with Reflection and can't find any examples that illustrate how to do something like this. So... is this possible with Reflection? Is there a better way to accomplish the same thing? I'll post the relevant code tomorrow when I'm back at my work computer.
Thanks,
Daniel
As promised, the code:
[GridAction]
public ActionResult _GetGrid()
{
IQueryable<Form> result = formRepository.GetAll();
foreach (Form f in result)
{
f.LineItems = null;
f.Notes = null;
}
return View(new GridModel<Form> { Data = result });
}
An added wrinkle is that I'm using the new Telerik MVC Extensions, so I'm not actually serializing the Json myself -- I'm just returning the IQueryable in an IGridModel, and the action filter [GridAction] does the rest.
So, just in case anyone's curious, here's how I finally solved this problem: I modified Damien Guard's T4 template to include the attribute [ScriptIgnore] above entities of type Association. This lets the JSON serializer know to not bother serializing these, thus preventing the circular reference problem I was getting. The generated code ends up looking like this:
private EntitySet<LineItem> _LineItems;
[ScriptIgnore]
[Association(Name=#"Form_LineItem", Storage=#"_LineItems", ThisKey=#"Id", OtherKey=#"FormId")]
public EntitySet<LineItem> LineItems
{
get {
return _LineItems;
}
set {
_LineItems.Assign(value);
}
}
This fixes the serialization problem I was having without disabling the use of child tables through LINQ. The grid action on the controller ends up looking like this:
[GridAction]
public ActionResult _GetGrid()
{
return View(new GridModel<Form> { Data = formRepository.GetAll() });
}
There are two options, one is to ignore those properties during serialization using [XmlIgnore]. The other one is to nullify the properties using reflection.
Ignore in serialization, simple usage sample that shows how to use default value in serialization:
[Serializable]
public class MyClass
{
[XmlIgnore]
public int IgnoredVal { get; set; }
public int Val { get; set; }
}
public void UsageSample()
{
var xmlSerializer = new XmlSerializer(typeof(MyClass));
var memoryStream = new MemoryStream();
var toSerialize = new MyClass { IgnoredVal = 1, Val = 2 };
xmlSerializer.Serialize(memoryStream, toSerialize);
memoryStream.Position = 0;
var deserialize = (MyClass)xmlSerializer.Deserialize(memoryStream);
Assert.AreEqual(0, deserialize.IgnoredVal);
Assert.AreEqual(2, deserialize.Val);
}
Nullify with reflection, code sample:
public void NullifyEntitySetProperties(object obj)
{
var entitySetProperties = obj.GetType().GetProperties()
.Where(property => property.PropertyType == typeof(EntitySet));
foreach (var property in entitySetProperties)
{
property.SetValue(obj, null, null);
}
}
In my opinion, if the first option can be done used in your code it's better. This option is more direct and economic.

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