The code below is updating the correct values into the OBJECT_TYPES table, but the OBJECT_ITEMS table is being overwritten but I am not sure why. Can anyone help?
var templateId = Request["id"].AsInt();
var dbcontext = new STDEntities1();
var query = dbcontext.OBJECT_TYPES.Where(o => o.ID == templateId);
var template = query.FirstOrDefault();
var newItem = new OBJECT_TYPES
{
CATEGORY_ID = template.CATEGORY_ID,
COMPANY_ID = template.COMPANY_ID,
OBJECT_NAME = "** Select A Name **",
HEIGHT = template.HEIGHT,
WIDTH = template.WIDTH,
TEMPLATE = template.ID
};
foreach (var field in template.OBJECT_ITEMS)
{
newItem.OBJECT_ITEMS.Add(field);
}
dbcontext.OBJECT_TYPES.Add(newItem);
dbcontext.SaveChanges();
this is happening because you are adding field which actually is an object that is being tracked by the dataContext/dbContext and even has an id. So the values are being overwritten.
Try creating the a new field OR try detaching the field from the context and then put the Id/Primary key to 0 and try inserting it again.
Related
I'm fairly new at MVC and linq and viewmodels in particular. I managed to get a create and index views to work. The "insert" wasn't as hard as the "list".
I have this linq query:
public ActionResult Index()
{
List<BlendElVM> BEVM = new List<BlendElVM>();
var list = (from Blend in db.blends
join BlendEl in db.blendEl on Blend.ID equals BlendEl.ID
select new
{
Blend.ID, Blend.Title, Blend.TransDt, BlendEl.Comment
}).ToList();
foreach (var item in list)
{
BlendElVM o = new BlendElVM(); // ViewModel
o.Comment = item.Comment;
o.Title = item.Title;
o.TransDt = item.TransDt;
o.ID = item.ID;
BEVM.Add(o);
}
return View(BEVM);
}
What I'm not sure about is the "foreach" section. When I'm running in debug, the "list" shows up fine, but if I comment out the "foreach" I get an error - ie not expecting the model. What does the foreach do? It has to do with the database, but I don't understand the where it is using the "o" and setting the columns. I thought it would all be in one linq query. Is it possible to combine the two and eliminate the "foreach"?
var BEVM = (from blend in db.blends
join BlendEl in db.blendEl on Blend.ID equals BlendEl.ID
select new BlendELVM
{
ID = blend.ID,
Title = blend.Title,
TransDT = blend.TransDt,
comment = blendEl.Comment
}).ToList();
I believe that the foreach is needed in order to read every element in the object so in this case you have:
BlendElVM o = new BlendElVM();
So you're creating and object named " o " of the type BlendELVM and this object contains all the attributes that you declared before which are: ID, Title, TransDT, etc
When you put:
foreach (var item in list)
{
BlendElVM o = new BlendElVM(); // ViewModel
o.Comment = item.Comment;
o.Title = item.Title;
o.TransDt = item.TransDt;
o.ID = item.ID;
BEVM.Add(o);
}
You're assigning to the new object o the item that you're reading in the list and in the end adding it to the BVEM list and answering if you can combine them i will say no because at first you're declaring the query and then you're reading the items on the list and assining them to the BEVM list
My Controller
public ActionResult Index()
{
TechnicianFacade _oTechFacade = new TechnicianFacade();
Maintenance_.Models.IndexModel _oTechModel = new Maintenance_.Models.IndexModel();
IList<Maintenance_.Models.IndexModel> _otechList = new List<Maintenance_.Models.IndexModel>();
var tech = _oTechFacade.getTechnicians("", _oAppSetting.ConnectionString).ToArray();
foreach (var test in tech)
{
string fName = test.GetType().GetProperty("FIRSTNAME").GetValue(test, null).ToString();
_oTechModel.firstName = fName;
_otechList.Add(_oTechModel); <===
}
_oTechModel.fNameList = _otechList;
return View("Index", _oTechModel);
}
In my controller: index, can get all data object from my database. But if I have more than one data object in my database the: _otechList.Add(_otechModel) will overwrite the first entry with the newly added data, like for example lets just say we have 2 object data: (FIRST loop of foreach) _otechList.Add(_oTechModel) has a data of "FIRSTNAME" = "GEM" where count = 0, (SECOND loop of foreach) _otechList.Add(_oTechModel) has a data of "FIRSTNAME" = "DIAMOND" where count = 1, this time the value of count[0] became "FIRSTNAME" = "DIAMOND" as well. Is there something missing in my code or there's something wrong on it?
It will replace because same object value is changed, you need to instantiate object inside foreach loop.
Maintenance_.Models.IndexModel _oTechModel = new Maintenance_.Models.IndexModel();
like this:
foreach (var test in tech)
{
string fName = test.GetType().GetProperty("FIRSTNAME").GetValue(test, null).ToString();
Maintenance_.Models.IndexModel _oTechModel = new Maintenance_.Models.IndexModel();
_oTechModel.firstName = fName;
_otechList.Add(_oTechModel);
}
your object is global so every time same object is added in the list, instantiate it inside foreach loop so that every time new object is added in the list.
How can I do a where in a query on a list or table ?
To explain, I have a multiselect listbox where the user can select one or many values which are passed to my action. After that, I get all this values in a list and I want to do a Where on it like that :
List<string> CondCR = new List<string>();
foreach (var testCR in SubCR)
{
CondCR.Add(testCR);
}
ViewBag.CondCR = CondCR;
var query = (from i in items
where i.Field<String>("TIMING").Contains(GetTIMING) && i.Field<String>("CD_CR").Equals(CondCR)
select new Suivi{CD_CR = i.Field<String>("CD_CR"), CD_APPLI = i.Field<String>("CD_APPLI"), CD_TRT = i.Field<String>("CD_TRT"), LB_TRT = i.Field<String>("LB_TRT"),
PERIODE = i.Field<Int64>("PERIODE"), CD_JOB = i.Field<String>("CD_JOB"), LB_JOB = i.Field<String>("LB_JOB"), CD_TYP_TRT = i.Field<String>("CD_TYP_TRT"),
CD_TRT_SSIS = i.Field<String>("CD_TRT_SSIS"), DT_DEB = i.Field<DateTime>("DT_DEB"), DT_FIN = i.Field<DateTime>("DT_FIN"), DUREE = i.Field<String>("DUREE"),
TIMING = i.Field<String>("TIMING")
}).ToList();
return View(query);
SubCR contains the value that the user select in the list box, SubCR is of type string[].
I've tried to do a where on my list CondCR but it returns nothing and I don't know if it comes from my query or from an other thing.
Have you some suggestions ?
Okay, I've find the answer, I just had to do this in my query :
where CondCR.Contains(i.Field<String>("CD_CR").Trim()) && CondAppli.Contains(i.Field<String>("CD_APPLI").Trim())
Few days back I put a question regarding mapping two classes Message and MessageStatusHistory using EF. The mapping is going fine but I am facing some problems with the navigation property StatusHistory in class Message that relates it to MessageStatusHistory objects. I am loading the messages for one user only and want to the statuses pertaining to that user only. Like I would want to show if the user has marked message as read/not-read and when. If I use default loading mechanism like following it loads all the history related to the message irrespective of the user:
IDbSet<Message> dbs = _repo.DbSet;
dbs.Include("StatusHistory").Where(x=>x.MessageIdentifier == msgIdentifier);
To filter history for one user only I tried following trick:
IDbSet<Message> dbs = _repo.DbSet;
var q = from m in dbs.Include("StatusHistory")
where m.MessageIdentifier == msgIdentifier
select new Message
{
MessageIdentifier = m.MessageIdentifier,
/*OTHER PROPERTIES*/
StatusHistory = m.StatusHistory
.Where(x => x.UserId == userId).ToList()
};
return q.ToList();//THROWING ERROR ON THIS LINE
I am getting the error:
The entity or complex type 'MyLib.Biz.Message' cannot be constructed in a LINQ
to Entities query.
I have tried by commenting StatusHistory = m.StatusHistory.Where(x => x.UserId == userId).ToList() also but it has not helped.
Please help me in getting Messages with filtered StatusHistory.
EDIT:- above is resolved with this code:
var q = from m in _repository.DBSet.Include("Histories")
where m.MessageIdentifier == id
select new {
m.Id,/*OTHER PROPERTIES*/
Histories = m.Histories.Where(x =>
x.SenderId == userId).ToList()
};
var lst = q.ToList();
return lst.Select(m => new Message{
Id = m.Id, MessageIdentifier = m.MessageIdentifier,
MessageText = m.MessageText, Replies = m.Replies,
ReplyTo = m.ReplyTo, Histories = m.Histories, SenderId =
m.SenderId, SenderName = m.SenderName, CreatedOn = m.CreatedOn
}).ToList();
But if I try to include replies to the message with:
from m in _repository.DBSet.Include("Replies").Include("Histories")
I am getting error on converting query to List with q.ToList() for Histories = m.Histories.Where(x=> x.SenderId == userId).ToList().
About your EDIT part: You cannot use ToList() in a projection, just leave it an IEnumerable<T> and convert to a List<T> when you construct the Message. You also don't need to create two list objects, you can switch from the LINQ to Entities query to LINQ to Objects (the second Select) by using AsEnumerable():
var list = (from m in _repository.DBSet
where m.MessageIdentifier == id
select new {
// ...
Histories = m.Histories.Where(x => x.SenderId == userId)
})
.AsEnumerable() // database query is executed here
.Select(m => new Message {
// ...
Histories = m.Histories.ToList(),
// ...
}).ToList();
return list;
Be aware that Include has no effect when you use a projection with select. You need to make the properties that you want to include part of the projection - as you already did with select new { Histories.....
I have a rather simple scenario where I have two tables in which I want to add data. They are managed with primary key/foreign key. I want to add new data into TABLE A and then retrieve the Id and insert into TABLE B.
I can certainly do it with a stored procedure, but I'm looking at trying to do it using Linq.
What is the best approach ?
I can certainly get the ID and do two separate inserts but that doesn't certainly seem to be a very good way of doing things.
db.Table.InsertOnSubmit(dbObject);
db.SubmitChanges();
Int32 id = dbOject.Id;
//Rest of the code
Any way to elegantly do this?
Do you have the relationship defined between the 2 tables in the object relational designed? If so, you can have linq take care of assigning the ID property of the second table automatically.
Example...
Table A – Order
OrderId
OrderDate
Table B – Order Item
OrderItemId
OrderId
ItemId
Code (Using LINQ-to-SQL):
Order order = new Order();
Order.OrderDate = DateTime.Now();
dataContext.InsertOnSubmit(order);
OrderItem item1 = new OrderItem();
Item1.ItemId = 123;
//Note: We set the Order property, which is an Order object
// We do not set the OrderId property
// LINQ will know to use the Id that is assigned from the order above
Item1.Order = order;
dataContext.InsertOnSubmit(item1);
dataContext.SubmitChanges();
hi i insert data into three table using this code
Product_Table AddProducttbl = new Product_Table();
Product_Company Companytbl = new Product_Company();
Product_Category Categorytbl = new Product_Category();
// genrate product id's
long Productid = (from p in Accountdc.Product_Tables
select p.Product_ID ).FirstOrDefault();
if (Productid == 0)
Productid++;
else
Productid = (from lng in Accountdc.Product_Tables
select lng.Product_ID ).Max() + 1;
try
{
AddProducttbl.Product_ID = Productid;
AddProducttbl.Product_Name = Request.Form["ProductName"];
AddProducttbl.Reorder_Label = Request.Form["ReorderLevel"];
AddProducttbl.Unit = Convert.ToDecimal(Request.Form["Unit"]);
AddProducttbl.Selling_Price = Convert.ToDecimal(Request.Form["Selling_Price"]);
AddProducttbl.MRP = Convert.ToDecimal(Request.Form["MRP"]);
// Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl );
// genrate category id's
long Companyid = (from c in Accountdc.Product_Companies
select c.Product_Company_ID).FirstOrDefault();
if (Companyid == 0)
Companyid++;
else
Companyid = (from Ct in Accountdc.Product_Companies
select Ct.Product_Company_ID).Max() + 1;
Companytbl.Product_Company_ID = Companyid;
Companytbl.Product_Company_Name = Request.Form["Company"];
AddProducttbl.Product_Company = Companytbl;
//Genrate Category id's
long Categoryid = (from ct in Accountdc.Product_Categories
select ct.Product_Category_ID).FirstOrDefault();
if (Categoryid == 0)
Categoryid++;
else
Categoryid = (from Ct in Accountdc.Product_Categories
select Ct.Product_Category_ID).Max() + 1;
Categorytbl.Product_Category_ID = Categoryid;
Categorytbl.Product_Category_Name = Request.Form["Category"];
AddProducttbl.Product_Category = Categorytbl;
Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl);
Accountdc.SubmitChanges();
}
catch
{
ViewData["submit Error"] = "No Product Submit";
}