RequiredField Validator to Validate more than 3 (Three) character in ASP.Net

Hi SUJAYS,

Using RequiredFieldValidator it is not possible to validate character length.

You have to use RegularExpressionValidator or JavaScript.

Check this example. Now please take its reference and correct your code.

HTML

<asp:TextBox runat="server" ID="txtName" ValidationGroup="G1" />
<asp:Button ID="Button1" Text="Validate" runat="server" ValidationGroup="G1" />
<br />
<asp:RequiredFieldValidator ControlToValidate="txtName" runat="server" ForeColor="Red"
    ErrorMessage="Required!" ValidationGroup="G1" Display="Dynamic" />
<asp:RegularExpressionValidator ControlToValidate="txtName" runat="server" ForeColor="Red"
    ErrorMessage="Enter more than 3 characters" ValidationGroup="G1" Display="Dynamic"
    ValidationExpression="[\S\s]{4,}" />

Screenshot