how combobox reset after postback

[Rahul]

how show empty message in combo box after post back page.

[Shinu]

Hi Rahul,

Please have a look into the following code snippet to achieve your scenario.

ASPX:

<telerik:RadComboBox ID="RadComboBox1" runat="server" AutoPostBack="true">
    <Items>
        <telerik:RadComboBoxItem Text="Item1" />
        <telerik:RadComboBoxItem Text="Item2" />
        <telerik:RadComboBoxItem Text="Item3" />
    </Items>
</telerik:RadComboBox>

One option is that you can set the EmptyMessage on the pageLoad event as follows.
JavaScript:

<script type="text/javascript">
    function pageLoad() {
        var combo = $find("<%=RadComboBox1.ClientID %>");
        combo.clearSelection();
        combo.set_emptyMessage("select");
    }
</script>

Another option is that you can set it from the server side Page_Load event as follows.
C#:

protected void Page_Load(object sender, EventArgs e)
{
    RadComboBox1.ClearSelection();
    RadComboBox1.EmptyMessage = "--select--";
}

Hope this will helps you.
Thanks,
Shinu.