我的要求是，如果用户在asp.net文本邮件，应验证从数据库中，无论是这封邮件的存在与否，并应停止提交表单，有没有内置的功能或我必须让自己？

My requirement is, if user enters email in asp.net textbox, it should validate from database, either this email exists or not, and should stop from submitting the form, is there any built in functionality or i have to make myself?

谢谢 与Atif

推荐答案

您必须做你自己。你可以使用AJAX

You have to do with yourself. You can use AJAX

 <asp:TextBox ID="txtEmail" runat="server" MaxLength="50"
        AutoPostBack="true" OnTextChanged="txtEmail_Changed"></asp:TextBox>
    <asp:RequiredFieldValidator ID="rfv" runat="Server" 
        ErrorMessage="*" ControlToValidate="txtEmail" Display="Dynamic" SetFocusOnError="True"></asp:RequiredFieldValidator>
    <asp:RegularExpressionValidator ID="RegularExpressionValidator6" runat="server" ControlToValidate="txtEmail"
        CssClass="ValidationError" Display="Dynamic" ErrorMessage="Invalid Email"
        ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*" SetFocusOnError="True"></asp:RegularExpressionValidator>

 <asp:UpdatePanel ID="upMessage" runat="Server" UpdateMode="Conditional">
      <Triggers>
         <asp:AsyncPostBackTrigger ControlID="txtEmail" EventName="TextChanged" />
       </Triggers>
   <ContentTemplate>
       <asp:Label ID="lbl" runat="server" Text=""></asp:Label>
    </ContentTemplate>
 </asp:UpdatePanel>

protected void txtEmail_Changed(object sender, EventArgs e)
    {
    // Write your code to check from DB
    }