About validator

Here is a code sample that uses RequiredFieldValidator together with CustomValidator. It validates both fields, as well as when one of them fails, and displays the error messages in the ValidationSummary.

 

The CustomValidator has OnServerValidate function in the code behind.

 

The .aspx markup:

Name:

ID="TextBox1" runat="server">

ID="RequiredFieldValidator1" runat="server"

EnableClientScript="false" ControlToValidate="TextBox1"

ErrorMessage="The 'Name' field cannot be empty!" Text="*"

ForeColor="Red" Display="Dynamic">

/> /> Number:

ID="TextBox2" runat="server">

ID="CustomValidator1" runat="server" ValidateEmptyText="true"

ControlToValidate="TextBox2" ErrorMessage="The 'Number' field must be exactly 5 digits!"

Text="*" ForeColor="Red" Display="Dynamic"

onservervalidate="CustomValidator1_ServerValidate">

ID="ValidationSummary1" runat="server"

HeaderText="Please check the following fields:"

ForeColor="Red" DisplayMode="BulletList" /> />

ID="Button1" runat="server" Text="Submit" />

 

and the validation function in .aspx.cs file:

protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)

{ if (args.Value.Length < 5 || args.Value.Length > 5)

{

args.IsValid = false;

}

else {

args.IsValid = true; }

}

Hope it will help

or you can visit

http://asp.net-tutorials.com/validation/required-field-validator/

https://www.codeproject.com/Articles/49527/How-to-Use-the-ASP-NET-Validation-Control-to-Valid

Hi,

 

 

Makes an input control a required field 

 

 

https://www.c-sharpcorner.com/UploadFile/puranindia/validation-controls-in-Asp-Net/

 

http://asp.net-tutorials.com/validation/required-field-validator/

 

https://www.aspsnippets.com/Articles/Display-ASPNet-Validators-RequiredFieldValidator-Validation-Error-Messages-inside-TextBox-Control.aspx