爲HTML中所需的輸入和字符串長度添加`asp：requiredfieldvalidator`

Question

如何在HTML中爲所需的輸入和字符串長度添加asp:requiredfieldvalidator？

I.e.用戶名是必需的，不能超過40個字符。

Answer 1

您CAND試試這個：

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 
<asp:RegularExpressionValidator Display = "Dynamic" ControlToValidate = "TextBox1" ID="RegularExpressionValidator1" ValidationExpression = "^[\s\S]{0,40}$" runat="server" ErrorMessage="Maximum 40 characters allowed."></asp:RegularExpressionValidator> 

編輯

您可以定期RegularExpressionValidator添加到您的RegularExpressionValidator這樣的：

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 
<asp:RegularExpressionValidator Display = "Dynamic" ControlToValidate = "TextBox1" ID="RegularExpressionValidator1" ValidationExpression = "^[\s\S]{0,40}$" runat="server" ErrorMessage="Maximum 40 characters allowed."> 

</asp:RegularExpressionValidator> 
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" controltovalidate="TextBox1" ErrorMessage="Required"></asp:RequiredFieldValidator>