With MVC 2's addition of the HtmlHelper EditorFor() it is not possible to create strongly typed Display and Editor templates for a given Model object and after fiddling with it I am a bit stumped as to how to pass additional Model data to the editor without losing the strong-typing of the editor control.
Classic Example: Product has Category. ProductEditor has a DropDownList for Category containing the names of all Categories. The ProductEditor is strongly typed to Product and we need to pass in the SelectList of Categories as well as the Product.
With a standard view we would wrap the Model data in a new type and pass that along. With the EditorTemplate we lose some of the standard functionality if we pass in a mixed Model containing more than one object (first thing I noticed was all of the LabelFor/TextBoxFor methods were producing entity names like "Model.Object" rather than just "Object").
Am I doing it wrong or should Html.EditorFor() have an additional ViewDataDictionary/Model parameter?
You can either create a custom ViewModel which has both properties OR you'll need to use ViewData to pass that information in.
I am still learning, but I had a similar problem for which I worked out a solution.
My Category is an enum and I use a template control which examines the enum to determine the contents for the Select tag.
It is used in the view as:
<%= Html.DropDownList
(
"CategoryCode",
MvcApplication1.Utility.EditorTemplates.SelectListForEnum(typeof(WebSite.ViewData.Episode.Procedure.Category), selectedItem)
) %>
The enum for Category is decorated with Description attributes to be used as the text values in the Select items:
public enum Category
{
[Description("Operative")]
Operative=1,
[Description("Non Operative")]
NonOperative=2,
[Description("Therapeutic")]
Therapeutic=3
}
private Category _CategoryCode;
public Category CategoryCode
{
get { return _CategoryCode; }
set { _CategoryCode = value; }
}
The SelectListForEnum constructs the list of select items using the enum definition and the index for the currently selected item, as follows:
public static SelectListItem[] SelectListForEnum(System.Type typeOfEnum, int selectedItem)
{
var enumValues = typeOfEnum.GetEnumValues();
var enumNames = typeOfEnum.GetEnumNames();
var count = enumNames.Length;
var enumDescriptions = new string[count];
int i = 0;
foreach (var item in enumValues)
{
var name = enumNames[i].Trim();
var fieldInfo = item.GetType().GetField(name);
var attributes = (DescriptionAttribute[])fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false);
enumDescriptions[i] = (attributes.Length > 0) ? attributes[0].Description : name;
i++;
}
var list = new SelectListItem[count];
for (int index = 0; index < list.Length; index++)
{
list[index] = new SelectListItem { Value = enumNames[index], Text = enumDescriptions[index], Selected = (index == (selectedItem - 1)) };
}
return list;
}
The end result is a nicely presented DDL.
Hope this helps. Any comments about better ways to do this will be greatly appreciated.
Try using ViewData.ModelMetadata this contains all of your class Annotations.
Excellent article http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-4-custom-object-templates.html
Related
I'm using Entity Framework 6 with ASP.Net MVC 5. When using a database context object, is there a way to use a variable for the table name, without having to manually write the query?
For example:
var tableName = "NameOfTable";
result = context.tableName.Find(...);
I know that particular code won't work, because tableName is not defined in context, but is there a way to achieve the desired effect?
There are some similar questions on this site, but they never really solved the problem and they were for earlier versions of entity framework, so I'm hoping that there is an answer now.
Here's a simple solution using a switch to associate a particular Type to a table. You could also maintain use some sort of Dictionary<string, Type> object.
var tableName = "Table1";
// Get proper return type.
Type returnType;
switch(tableName) {
case "Table1":
returnType = typeof(Table1EntityType);
break;
case "Table2":
returnType = typeof(Table2EntityType);
break;
}
var query = context.Set(returnType);
// Filter against "query" variable below...
var result = query.Where(...);
-or-
var tableName = "Table1";
Dictionary<string, Type> tableTypeDict = new Dictionary<string, Type>()
{
{ "Table1", Table1Type },
{ "Table2", Table2Type }
};
var query = context.Set(tableTypeDict[tableName]);
// Filter against "query" variable below...
var result = query.Where(...);
EDIT: Modified for Entity Framework
EDIT2: Use typeof per #thepirat000 's suggestion
In addition to the helpful answers above, I also want to add this in case it helps someone else.
If you are getting this error on the "Where" clause in Mark's answer:
'DbSet does not contain a definition for 'Where' and no acceptable extension method 'Where' accepting an argument of the type 'DbSet' could be found.
Installing the Nuget Package "System.Linq.Dynamic.Core" made the error disappear for us.
If you need to access the LINQ methods and the column names from the table, you can code something like this:
var tableName = "MyTableName";
var tableClassNameSpace = "MyProject.Models.EntityModels";
using (var dbContext = new MyEntities())
{
var tableClassName = $"{tableClassNameSpace}.{tableName}";
var dynamicTableType = Type.GetType(tableClassName); // Type
var dynamicTable = dbContext.Set(dynamicTableType); // DbSet
var records = dynamicTable
.AsQueryable()
.ToDynamicList()
.OrderBy(d => d.MyColumnName)
.Select(d => new { d.MyColumnName })
.ToList();
// do stuff
}
I am trying to setup a search in umbraco examine.I have two search fields ,material and manufacturer.when I trying to search with one material and one manufactuere it will give the correct result.but when try to search more than one material or manufacturer it doesn't give the result.here is my code
const string materialSearchFields = "material";
const string manufacturerSearchFields = "manufacturer";
if (!string.IsNullOrEmpty(Request.QueryString["material"]))
{
material = Helper.StripTags(Request.QueryString["material"]);
}
if (!string.IsNullOrEmpty(Request.QueryString["manufacturer"]))
{
manufacturer = Helper.StripTags(Request.QueryString["manufacturer"]);
}
if (!string.IsNullOrEmpty(Request.QueryString["material"]) || !string.IsNullOrEmpty(Request.QueryString["manufacturer"]))
{
var query = userFieldSearchCriteria.Field(materialSearchFields, material).And().Field(manufacturerSearchFields, manufacturer).Compile();
contentResults = contentSearcher.Search(query).ToList();
}
here my search keywors in querystring is material=iron,steel
how can we split this keyword and search done?
Thanks in advance for the help....
You are using the AND operator, in your case I think you are looking for the GROUPEDOR instead?
I was just working in an old project and grabbed this snipet from there (which I've adapted for your needs). I think it's going to help you:
public IEnumerable<DynamicNode> SearchUmbraco(string[] keywords, string currentCulture)
{
// In this case I had some diferent cultures, so this sets the BaseSearchProvider to the given culture parameter. You might not need this, use your default one.
BaseSearchProvider searcher = SetBaseSearchProvider(currentCulture);
var searchCriteria = searcher.CreateSearchCriteria(BooleanOperation.Or);
var groupedQuery = searchCriteria.GroupedOr(new[] {"manufacturer", "material"}, keywords).Compile();
var searchResults = searcher.Search(groupedQuery);
// ... return IEnumerable of dynamic nodes (in this snipet case)
}
I just split(etc) the keywords in an helper and pass them to a string array when I call this method.
Just check this infomation on the umbraco blog: http://umbraco.com/follow-us/blog-archive/2011/9/16/examining-examine.aspx
Is there a generic way to retrieve PropertyInfo based on a string value alone, when deeper than one level.
I assume this is probably simple enough, but my search results are only as good as my search criteria, and I think I am having an issue articulating the proper keywords to get search results for what I am after.
I would like to be able to do something like the following (which works perfect if the key is for a direct property / one level - ie key = 'firstName'):
public static PropertyInfo (this HtmlHelper htmlHelper, string key) {
PropertyInfo pInfo = htmlHelper.ViewData.Model.GetType().GetProperty(key);
return pInfo;
}
But is there a way for me to return the PropertyInfo based on a string alone
when Key equals something more complex, such as nested classes, objects, lists, etc...:
key = "somelist[0].myproperty"
key = "Items[0].someotherlist[1].someproperty" (where Items is defined as List<Item> Items {get; set;}, someotherlist is defined similarly)
Can the method be generic enough to essentially drill down as many levels as needed (defined)?
So here is what I came up with... this is about to get wordy, and mostly 'stream of thought'
I have custom HtmlHelperExtension, and within it :
PropertyInfo[] pInfoArray = htmlHelper.ViewData.Model.GetType().GetProperties();
PropertyInfo pInfo = GetPropertyInfo(pInfoArray, key);
This GetPropertyInfo() method takes the key, and the PropertyInfo array, cycles through the properties, until the keypart (using regex to remove any indication of an array from the string, so I am left with only the property) matches the property name. On Match, determine if this is the first cycle in the loop, and if so assign the matched property to my Temp Type and PropertyInfo variables. If keyParts are remaining to loop through, subsequent loops now use previously set temp variables and the for loop index [i] to iterate / drill down the class structure. Each time setting the pInfoTemp variable, and then pTypeTemp so the next loop can use where it left off.
private static PropertyInfo GetPropertyInfo(PropertyInfo[] pInfoArray, string key)
{
PropertyInfo pInfo = null;
string[] keyParts = key.Split('.');
Regex arrayRgx = new Regex("\\[\\d*\\]");
PropertyInfo pInfoTemp = null;
Type pTypeTemp = null;
foreach (PropertyInfo prop in pInfoArray)
{
string keyPartsTrimmed = arrayRgx.Replace(keyParts[0], ""); // removes '[#]' from string
if (keyPartsTrimmed == prop.Name) // match property name
{
for (int i = 0; i < keyParts.Count(); i++)
{
if (i == 0) // initial item [0]
{
pTypeTemp = prop.PropertyType; // gets [0]'s type
pInfoTemp = prop; // assigns [0]'s property info
}
else
{
pInfoTemp = GetNestedPropertyInfo(pTypeTemp, arrayRgx.Replace(keyParts[i], "")); // gets [i]'s property info for return or next iteration
pTypeTemp = pInfoTemp.PropertyType; // gets [i]'s type for next iteration
}
}
pInfo = pInfoTemp;
break;
}
}
return pInfo;
}
This next method is invoked by the previous for grabbing nested property info, more importantly for detecting whether the passedItemType is a List (without this, it fails to work correctly as it is unable to find the property asked for in a List<> Type. I need to know what the List item Type is.
private static PropertyInfo GetNestedPropertyInfo(Type passedItemType, string passedProperty)
{
PropertyInfo pInfoOut = null;
if (passedItemType.IsGenericType && passedItemType.GetGenericTypeDefinition() == typeof(List<>))
{
Type itemType = passedItemType.GetGenericArguments()[0];
pInfoOut = itemType.GetProperty(passedProperty);
}
else
{
pInfoOut = passedItemType.GetProperty(passedProperty);
}
return pInfoOut;
}
This currently suits my requirements as they are today, and I have tested it with the following properties, lists, subclasses, subclasses with lists, etc.. to 4 levels deep, but should function properly no matter the depth:
firstName
lastName
Items[1].sprocket
subClass.subClassInt
subClass.mySubClassObj.sprocketObj
subClass.ItemsInMySubClass[1].sprocket
subClass.ItemsInMySubClass[0].mySubClassObj.widgetObj
subClass.ItemsInMySubClass[2].mySubClassObj.sprocketObj
If anyone has a better solution, or see any potential issues with what I have, I welcome the feedback.
The best way in your case is to make a parser that split that expression.
What is the best practice in Dart when dealing with classes as data records?
To Elaborate: When writing an app, it is likely that a class for a table row will be created. As in
class Item { int itemid, String itemName, double score }
Item item = new Item();
This allows compile time catching of any typos etc. in Dart. (Unlike using a class that relies on NoSuchMethod.)
It will also need a corresponding string structure to bind to the HTML such as
<input id="itemname" type="text" bind-value="itemEdit.itemName">
So the Dart would be:
class ItemEdit { String itemId, String itemName, String score }
ItemEdit itemEdit = new ItemEdit();
Next we need a way to get from one to the other, so we add a method to Item
fromStrings(ItemEdit ie) {
itemid = ie.itemId == null ? null : int.parse(ie.itemId);
itemName = ie.ItemName;
score = ie.score == null ? null : double.parse(ie.score);
}
And the other way around:
toStrings(ItemEdit ie) {
ie.itemid = itemId == null ? '' : ie.itemId.toString();
ie. itemName = itemName == null ? '' : itemname; // Web_ui objects to nulls
ie.score = score == null ? null : score.toStringAsFixed(2);
}
Also, we get jason data from a database, so we need to add another method to Item:
fromJson(final String j) {
Map v = JSON.parse(j);
itemid = v['itemid'];
itemname = v['itemname'];
score = v['score'];
}
And we need to be able to revert to default values:
setDefaults() { itemId = 0; itemName = "New item"; score = 0; }
This verbosity gets me feeling like I am writing COBOL again!
There is something fundamental missing here - either in my understanding, or in the Dart/WebUI libraries.
What I would like to write is something like
class Item extends DataRecord {
int itemid = 0,
String itemName = 'New item',
double score = 0.0;
}
Then, without further coding, to be able to write code such as
item.toStrings();
...
item.fromStrings();
...
item.fromJson(json);
...
item.setDefaults(); // results in {0,'New item',0.0}
And to be able to write in the HTML:
value="{{item.strings.score}}"
If this was possible, it would be quicker, simpler, clearer, and less error prone than the code I am writing at the moment.
(Full disclosure, this answer is written with the assumption that at least one bug will be fixed. See below)
Three suggestions that might help.
Use named constructors to parse and create objects.
Take advantage of toJson() when encoding to JSON.
Use bind-value-as-number from Web UI
1) Named constructors
import 'dart:json' as json;
class Item {
int itemid;
String itemName;
double score;
Item.fromJson(String json) {
Map data = json.parse(json);
itemid = data['itemid'];
itemName = data['itemName'];
score = data['score'];
}
}
2) Encoding to JSON
The dart:json library has a stringify function to turn an object into a JSON string. If the algorithm encounters an object that is not a string, null, number, boolean, or collection of those, it will call toJson() on that object and expect something that is JSON-encodable.
class Item {
int itemid;
String itemName;
double score;
Map toJson() {
return {'itemid':itemid, 'itemName':itemName, 'score':score};
}
}
3) Now, having said that, sounds like you want to easily bind to HTML fields and get primitive values back, not just strings. Try this:
<input type="number" min="1" bind-value-as-number="myInt" />
(Note, there seems to be a bug with this functionality. See https://github.com/dart-lang/web-ui/issues/317)
(from https://groups.google.com/a/dartlang.org/forum/#!topic/web-ui/8JEAA5OxJOc)
Just found a way to perhaps help a little in the this situation:
class obj {
int gapX;
String get gapXStr => gapX.toString();
set gapXStr(String s) => gapX = int.Parse(s);
...
Now, from the HTML you can use, for example
bind-value="gapXStr"
and in code you can use
x += ob.gapX;
I'm writing an ASP.NET MVC 3 site and I need to convert some integer values from the database that represent statuses with user readable strings, for example:
...
<td>
#item.Status
</td>
...
I've written an HTML Helper to do the conversion:
public static string MessageType(this HtmlHelper helper, int type)
{
string messageType = "Unknown";
switch((Types.MessageTypes)type)
{
case Types.MessageTypes.Join:
messageType = "Join App";
break;
case Types.MessageTypes.New:
messageType = "New App";
break;
}
return messageType;
}
And I'm storing the types as an enumeration in the Types class.
My question is whether there is a cleaner way to do this? I don't like these magic strings in my code and it creates numerous dependencies in different parts of the code.
Any thoughts?
Many thanks,
Sam
I usual decorate the enums with the DisplayAttribute like this.
enum MessageTypes
{
[Display(Name = "Join App")]
Join,
[Display(Name = "New App")]
New
}
Then I use a helper to extract them:
public static string EnumDisplay(this HtmlHelper helper, Enum model)
{
var enumType = model.GetType();
var modelValue = Convert.ToInt64(model);
var matches = from field in enumType.GetMembers()
where field.MemberType == MemberTypes.Field && Enum.IsDefined(enumType, field.Name)
let value = Convert.ToInt64(Enum.Parse(enumType, field.Name, false))
where modelValue == value
let attribute = field.GetCustomAttributes(typeof (DisplayAttribute), false).Cast<DisplayAttribute>().FirstOrDefault()
select attribute == null
? field.Name
: attribute.Name;
return matches.FirstOrDefault() ?? "Unknown";
}
Then you can do
#Html.EnumDisplay((MessageType)item.MessageType)
In my opinion, you should be storing the corresponding user readable strings in the database next to the integer. And return an object e.g. StatusViewModel to the view model. the View model may have >
class StatusViewModel
{
int type;
string displayMessage;
}
makes sense?