为什么我的ASP.NET CustomValidator不会验证？

我一定做错了什么.我似乎无法执行我的CustomValidator的ServerValidate方法.

我有一个带有CustomValidator的Visual Basic ASP.NET页面......

对于这个测试,我的验证设置总是失败...

Sub CustomValidator1_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate
    args.IsValid = False
End Sub

但是,单击该按钮时,CustomValidator1_ServerValidate()方法永远不会执行!

Protected Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Page.Validate()
    If Page.IsValid Then
        'it executes the code here!
    End If
End Sub

即使我明确验证该控件...

CustomValidator1.Validate() 'does nothing?

我究竟做错了什么？

添加属性:

 ValidateEmptyText="True"