validations in asp.net

Validation groups allow you to organize validation controls on a page as a set. Each validation group can perform validation independently from other validation groups on the page.

You create a validation group by setting the ValidationGroup property to the same name (a string) for all the controls you want to group. You can assign any name to a validation group, but you must use the same name for all members of the group.

<form id="form1"  runat="server">

   <h3>Button.ValidationGroup Example</h3>

   <asp:label id="NameLabel" xmlns:asp="#unknown">
     text="Enter your name:"
     runat="Server"
     AssociatedControlID="NameTextBox">
   </asp:label>

    

   <asp:textbox id="NameTextBox" xmlns:asp="#unknown">
     runat="Server">
   </asp:textbox>

    

   <asp:requiredfieldvalidator id="RequiredFieldValidator1" xmlns:asp="#unknown">
     controltovalidate="NameTextBox"
     validationgroup="PersonalInfoGroup"
     errormessage="Enter your name."
     runat="Server">
   </asp:requiredfieldvalidator>

   <br /><br />

   <asp:label id="AgeLabel" xmlns:asp="#unknown">
     text="Enter your age:"
     runat="Server"
     AssociatedControlID="AgeTextBox">
   </asp:label>

    

   <asp:textbox id="AgeTextBox" xmlns:asp="#unknown">
     runat="Server">
   </asp:textbox>

    

   <asp:requiredfieldvalidator id="RequiredFieldValidator2" xmlns:asp="#unknown">
     controltovalidate="AgeTextBox"
     validationgroup="PersonalInfoGroup"
     errormessage="Enter your age."
     runat="Server">
   </asp:requiredfieldvalidator>

   <br /><br />

   <!--When Button1 is clicked, only validation
   controls that are a part of PersonalInfoGroup
   are validated.-->
   <asp:button id="Button1" xmlns:asp="#unknown">
     text="Validate"
     causesvalidation="true"
     validationgroup="PersonalInfoGroup"
     runat="Server" />

   <br /><br />

   <asp:label id="CityLabel">
     text="Enter your city of residence:"
     runat="Server"
     AssociatedControlID="CityTextBox">
   </asp:label>

    

   <asp:textbox id="CityTextBox">
     runat="Server">
   </asp:textbox>

    

   <asp:requiredfieldvalidator id="RequiredFieldValidator3">
     controltovalidate="CityTextBox"
     validationgroup="LocationInfoGroup"
     errormessage="Enter a city name."
     runat="Server">
   </asp:requiredfieldvalidator>

   <br /><br />

   <!--When Button2 is clicked, only validation
   controls that are a part of LocationInfoGroup
   are validated.-->
   <asp:button id="Button2">
     text="Validate"
     causesvalidation="true"
     validationgroup="LocationInfoGroup"
     runat="Server" />

 </asp:button></asp:button></form>

Source[^]

this is a working example. :
Validation group[^]

The ValidationGroup property specifies which group of control is validated on validation.

This property is mostly used when there are several buttons in a form.

Simple Examples:
Validation Group Sample[^]

Validation_group_in_ASPNet[^]