Using the EmptyMessage Property

The EmptyMessage property of the RadComboBox enables the ability to set any text in the input field of the control. The Empty Message property could be very useful, when one needs to provide more information in the input about the content of the RadComboBox. This text is not visible when the combobox gets the focus and appears again on blur if no item is selected.

Setting the EmptyMessage server-side

protected void Page_Load(object sender, EventArgs e)
{
   RadComboBox1.EmptyMessage = "Please select a country";
}

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    RadComboBox1.EmptyMessage = "Please select a country"

End Sub

Setting the EmptyMessage client-side

function onClientLoadHandler(sender, eventArgs) {

    sender.set_emptyMessage("Please select a country");
}

Additionally, you can get the EmptyMessage property client-side by calling the get_emptyMessage() method of the combobox.

Controlling the appearance of the EmptyMessage text

To control the appearance of the EmptyMessage text you can change this CSS rule:

.RadComboBox_Default .rcbInputCell .rcbEmptyMessage 
{ 
    color: #666; font-style: italic;
}

Here Default is the name of the Skin of the combobox.