自定义验证器不适用于文本框

Question

我正在学习如何使用自定义验证器进行服务器端验证，但我似乎无法让它工作。每当我单击按钮时，文本框为空，错误消息就不会显示。我究竟做错了什么？

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

<asp:CustomValidator ID="CustomValidator1" ControlToValidate="TextBox1"
     OnServerValidate="CustomValidator1_ServerValidate" ValidationGroup="ValidateGp"
     ErrorMessage="This is a custom error validator" runat="server"/>

<asp:Button ID="Button1" runat="server" Text="Button" ValidationGroup="ValidateGp"/>

protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
{
    if (args.Value.Equals(string.Empty))
    {
        args.IsValid = false;
    }
    else
    {
        args.IsValid = true;
    }
}

Answer 1

你错过了 ValidateEmptyText="true"

<asp:CustomValidator ID="CustomValidator1"
                    ValidateEmptyText="true" runat="server" ValidationGroup="ValidateGp" ErrorMessage="This is a custom error validator" ControlToValidate="TextBox1" OnServerValidate="CustomValidator1_ServerValidate"></asp:CustomValidator>