Message window using VB.NET in ajax

This article is used to show message window in vb.net using ajax. The problem comes when you use vb.net using ajax enables website.. This concept is easy to use in C# but it is not easy in vb.net. I am writing two line code for this message window.

Private Sub DisplayClientError(ByVal errorDesc As String)
Dim script As String = "alert('" + errorDesc + "');"
ScriptManager.RegisterStartupScript(Me, GetType(Page), "UserSecurity", script, True)
End Sub 'DisplayClientError write this code on click event where you want show message window
Protected Sub ClickButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles ClickButton.Click
If TextBox1.Text = "" Then
DisplayClientError("Enter some text in text box")
End If
End Sub

Screen Shot