ASP:DropDownList in ItemTemplate: Why is SelectedValue attribute allowed?

Question

This piece of code

Answer 1

It means you cannot set it through the designer.

The correct way is:

<asp:DropDownList runat="server" ID="testdropdown">
    <asp:ListItem Text="1" Value="1"></asp:ListItem>
    <asp:ListItem Text="2" Value="2" Selected></asp:ListItem>
    <asp:ListItem Text="3" Value="3"></asp:ListItem>
</asp:DropDownList>

The reason the bound method works is because the value isn't selected in design mode but at runtime after the control is bound to a datasource

The DropDownList.SelectedValue method is meant to be applied at runtime hence the error about not being able to set it 'decoratively'

Answer 2

in markup use SelectedValue='<%# "32" %>' syntax .(note the order of single and then the double quotes in the following example ):

 <asp:DropDownList  ID="ddlField" SelectedValue='<%# "32" %>' 
   runat="server"   DataTextField="Name" DataValueField="ID"  >
  </asp:DropDownList>

or in code-behind just after DataBinding .(example):

  ddlField.DataSource = Fields.SelectAll();
  ddlField.DataBind();           
  ddlField.SelectedValue = "32";