Bind Data to DropDownList in GridView asp.net

asp.net

I have web form with a GridView and a few controls in the GridView. I have a DropDownList in the EdtItemTemplate of the gridview.

I am needing to bind this DropDownList with some method in my CodeBehind File that returns a Array of type LisItems.

The problem I am facing is this. Since the Control is sitting in the EditItemTemplate, using the FindControl("MyControlID") does not seem to work in any of the GridView events, it returns null, in other words it cannot seem to find the control, unless I use the OnRowUpdating event, but I cannot use this event as the Control needs to be Data binded before that.

Is there anyway I can use the <%# Bind("MyMethodName") %> to bind the control?

Best Answer

Try this

Create a class of your data in App_Code, Like this

public static class Fruits
{
    public static List<string> GetFruits()
    {
        return new string[] { "Apple", "Mango", "Banana", "Grapes" }.ToList();
    }
}

Add a grid to your page, Which I guess you all ready have

<asp:GridView runat="server" ID="grid" AutoGenerateColumns="false" OnRowEditing="grid_RowEditing">
        <Columns>
            <asp:TemplateField HeaderText="Selected Fruit">
                <ItemTemplate>
                    <asp:Label runat="server" ID="Fruit" Text='<%# Eval("Fruits") %>' />
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:DropDownList runat="server" ID="fruits" DataSourceID="fruitsDS" />
                </EditItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Edit">
                <ItemTemplate>
                    <asp:Button runat="server" ID="btnEdit" Text="Edit" CommandName="Edit" />
            </ItemTemplate>
      </asp:TemplateField>
    </Columns>
</asp:GridView>

And add an Object Datasource to bind your DropDowns of edit template

<asp:ObjectDataSource ID="fruitsDS" runat="server" SelectMethod="GetFruits" TypeName="Fruits" />

Hope this could help.

For MVC v5.1 use Html.EnumDropDownListFor

@Html.EnumDropDownListFor(
    x => x.YourEnumField,
    "Select My Type", 
    new { @class = "form-control" })

For MVC v5 use EnumHelper

@Html.DropDownList("MyType", 
   EnumHelper.GetSelectList(typeof(MyType)) , 
   "Select My Type", 
   new { @class = "form-control" })

For MVC 5 and lower

I rolled Rune's answer into an extension method:

namespace MyApp.Common
{
    public static class MyExtensions{
        public static SelectList ToSelectList<TEnum>(this TEnum enumObj)
            where TEnum : struct, IComparable, IFormattable, IConvertible
        {
            var values = from TEnum e in Enum.GetValues(typeof(TEnum))
                select new { Id = e, Name = e.ToString() };
            return new SelectList(values, "Id", "Name", enumObj);
        }
    }
}

This allows you to write:

ViewData["taskStatus"] = task.Status.ToSelectList();

by using MyApp.Common

.net – ASP.NET Web Site or ASP.NET Web Application

Website:

The Web Site project is compiled on the fly. You end up with a lot more DLL files, which can be a pain. It also gives problems when you have pages or controls in one directory that need to reference pages and controls in another directory since the other directory may not be compiled into the code yet. Another problem can be in publishing.

If Visual Studio isn't told to re-use the same names constantly, it will come up with new names for the DLL files generated by pages all the time. That can lead to having several close copies of DLL files containing the same class name, which will generate plenty of errors. The Web Site project was introduced with Visual Studio 2005, but it has turned out not to be popular.

Web Application:

The Web Application Project was created as an add-in and now exists as part of SP 1 for Visual Studio 2005. The main differences are the Web Application Project was designed to work similarly to the Web projects that shipped with Visual Studio 2003. It will compile the application into a single DLL file at build time. To update the project, it must be recompiled and the DLL file published for changes to occur.

Another nice feature of the Web Application project is it's much easier to exclude files from the project view. In the Web Site project, each file that you exclude is renamed with an excluded keyword in the filename. In the Web Application Project, the project just keeps track of which files to include/exclude from the project view without renaming them, making things much tidier.

Reference

The article ASP.NET 2.0 - Web Site vs Web Application project also gives reasons on why to use one and not the other. Here is an excerpt of it:

You need to migrate large Visual Studio .NET 2003 applications to VS 2005? use the Web Application project.

You want to open and edit any directory as a Web project without creating a project file? use Web Site project.

You need to add pre-build and post-build steps during compilation? use Web Application project.

You need to build a Web application using multiple Web projects? use the Web Application project.

You want to generate one assembly for each page? use the Web Site project.

You prefer dynamic compilation and working on pages without building entire site on each page view? use Web Site project.

You prefer single-page code model to code-behind model? use Web Site project.

Web Application Projects versus Web Site Projects (MSDN) explains the differences between the web site and web application projects. Also, it discusses the configuration to be made in Visual Studio.