Problem

For past few days I have been facing a problem while dynamically making a list item selected. Here is the code that I have used.

Code

ASPX
    
        <asp:DropDownList ID="DropDownList1" runat="server"  Width="150px">
            <asp:ListItem Value="0" Text="-- Select --" Selected="True"/>
            <asp:ListItem Value="1" Text="Red" />
            <asp:ListItem Value="2" Text="Greeen" />
            <asp:ListItem Value="3" Text="Yellow" />
            <asp:ListItem Value="4" Text="Pink" />
            <asp:ListItem Value="5" Text="-- All --" />
    </asp:DropDownList>

    C#
    
      protected void Page_Load(object sender, EventArgs e)
    {
        ListItem item = DropDownList1.Items.FindByValue("5");
        if (item != null)
            item.Selected = true;
    }

However, the code generates the following exception:

Solution

1.  Just add the following codes before calling FindByValue() or FindByText()

      protected void Page_Load(object sender, EventArgs e)
        {
            DropDownList1.ClearSelection(); // New code added

            ListItem item = DropDownList1.Items.FindByValue("5");
            if (item != null)
                item.Selected = true;            
        }
        
    2.  Also the following code works fine
        
        protected void Page_Load(object sender, EventArgs e)
        {
             DropDownList1.SelectedIndex = 5;            
        }

I hope this helps and saves your time. Happy coding