[DotNetDevelopment] What's wrong with my C# / ASP .NET code?

[Dixie Normous]

I'm trying to populate a DataList object in an ASP .NET website app.

Here is the DataList and its ObjectDataSource as defined in my .aspx
page:

<asp:DataList ID="dlThumbNails" runat="server"
DataKeyField="ProductID" DataSourceID="ObjectDataSource1"
EnableViewState="False">
<ItemTemplate>
<asp:Image runat="server" ImageURL='<%# ((Imagez)
Container.DataItem).URL %>' />
</ItemTemplate>
</asp:DataList>

<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
OldValuesParameterFormatString="original... SelectMethod="GetImages"
TypeName="WebApplication1._Default"> </asp:ObjectDataSource>

Here is the GetImages method from my code-behind

public void GetImages()
{
          int iCount;
          string sURL;

          List<string> URLs = new List<string>();

          List<Imagez> myImagez = new List<Imagez>();

          for (iCount = 0; iCount <= 20; iCount++)
          {
                    URLs.Add(@"<img src='http://mylink.com/image"; +
iCount.ToString() + ".jpg'></img>";

                    sURL = URLs[iCount];

                    Imagez test = new Imagez();

                    test.URL = sURL;

                    myImagez.Add(test);
          }

          dlThumbNails.DataSource = myImagez;
          dlThumbNails.DataBind();

}

When I debug the app, I get the following error:

          Object reference not set to an instance of an object.
          dlThumbNails.DataSource = myImagez;

The DataList object in the debugger is NULL, although my object
myImagez is populated and has data.

What's wrong with my code?  Please help, thank you!!!