Validation Controls in Asp.Net

Validating user input is a common scenario in a Web-based application. For production applications, developers often end up spending a lot more time and code on this task than we would like. In building the ASP.NET page framework, it was important to try and make the task of validating input a lot easer than it has been in the past.

VALIDATION CONTROLS

The Validation is used to validate an input data.

TYPES OF VALIDATION

There are different types of Validator . They are:

Required Field Validator

Range Validator

Compare Validator

Regular Expression Validator

Custom Validator

Validator Summary

Required Field Validator

It make an input Control as a required Field.

Example


<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
<asp:Button ID="Button1" runat="server" Text="Click Me" />

Range Validator

It Checks the user input is between Two value.It is possible to check ranges within numbers, dates, and characters

Examples


             <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                <asp:RangeValidator ID="RangeValidator1" runat="server" ControlToValidate="TextBox1"
                    MinimumValue="1" MaximumValue="100" ErrorMessage="Enter 1 to 100" Type="Integer" Text="*"></asp:RangeValidator>
<asp:Button ID="Button1" runat="server" Text="Click Me" />

Compare Validator

It is used to compare one input value to the another input value

Examples


 <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:CompareValidator ID="CompareValidator1" runat="server" ErrorMessage="Sno and Emp No are Different"
                    ControlToCompare="TextBox1" ControlToValidate="TextBox1" Text="*"></asp:CompareValidator>
<asp:Button ID="Button1" runat="server" Text="Click Me" />

Regular Expression validator

It Refers the input values refer the special pattern

Example

 
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
               <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="Email is not valid"
                    ControlToValidate="TextBox3" ValidationExpression="^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$" Text="*"></asp:RegularExpressionValidator>              
<asp:Button ID="Button1" runat="server" Text="Click Me" />

Custom validator

It allows you to write a method to handle the validation of the value entered.

Example

 
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                <asp:CustomValidator ID="CustomValidator1" runat="server" ControlToValidate="TextBox4"
                    OnServerValidate="username" ErrorMessage="Enter 2 to 9 letter" Text="*"></asp:CustomValidator>            
<asp:Button ID="Button1" runat="server" Text="Click Me" />



    <script language ="vbscript"  runat="server">
        Sub username(ByVal source As Object, ByVal args As ServerValidateEventArgs)
            If Len(args.Value) < 2 Or Len(args.Value) > 9 Then
                args.IsValid = False
            Else
                args.IsValid = True
            End If
        End Sub

   </script>

validation Summary

It is used to display a summary of all validation errors occurred in a Web page.

Example:


<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

    <script language ="vbscript"  runat="server">
        Sub username(ByVal source As Object, ByVal args As ServerValidateEventArgs)
            If Len(args.Value) < 2 Or Len(args.Value) > 9 Then
                args.IsValid = False
            Else
                args.IsValid = True
            End If
        End Sub

    </script>

</head>
<body>
    <form id="form1" runat="server">
    <table width="100%" cellpadding="0" cellspacing="0">
        <tr>
            <td>
                <asp:Label ID="Label1" runat="server" Text="Sno"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
                <asp:RangeValidator ID="RangeValidator1" runat="server" ControlToValidate="TextBox1"
                    MinimumValue="1" MaximumValue="100" ErrorMessage="Enter 1 to 100" Type="Integer" Text="*"></asp:RangeValidator>
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label2" runat="server" Text="Emp No"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
                <asp:CompareValidator ID="CompareValidator1" runat="server" ErrorMessage="Sno and Emp No are Different"
                    ControlToCompare="TextBox1" ControlToValidate="TextBox2" Text="*"></asp:CompareValidator>
            <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="TextBox2"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label4" runat="server" Text="User Name"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>
                <asp:CustomValidator ID="CustomValidator1" runat="server" ControlToValidate="TextBox4"
                    OnServerValidate="username" ErrorMessage="Enter 2 to 9 letter" Text="*"></asp:CustomValidator>
             <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="TextBox4"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
            </td>
        </tr>
        <tr>
        <td>
            <asp:Label ID="Label5" runat="server" Text="Password"></asp:Label>
        </td>
        <td>
            <asp:TextBox ID="TextBox5" runat="server"></asp:TextBox>
             <asp:RegularExpressionValidator ID="RegularExpressionValidator2" runat="server" ErrorMessage="ENTER 8 T0 10 CHARACTER WITH ALPHANUMERIC CHATRACTER WITH SPECIAL CHARACTER "
                    ControlToValidate="TextBox5" ValidationExpression="(?=^.{8,12}$)(?=.*\d)(?=.*\W+)(?![.\n]).*$" Text="*"></asp:RegularExpressionValidator>
             <asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server" ControlToValidate="TextBox5"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
        </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label3" runat="server" Text="Email"></asp:Label>
            </td>
            <td>
                <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
                <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="Email is not valid"
                    ControlToValidate="TextBox3" ValidationExpression="^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$" Text="*"></asp:RegularExpressionValidator>
             <asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server" ControlToValidate="TextBox3"
                    ErrorMessage="Value Required" Text="*"></asp:RequiredFieldValidator>
            </td>
        </tr>
        <tr>
            <td>
                <asp:Button ID="Button1" runat="server" Text="Click Me" />
            </td>
        </tr>
        <tr>
            <asp:ValidationSummary ID="ValidationSummary1" runat="server" HeaderText="You must enter a value in the following fields:" DisplayMode ="BulletList" EnableClientScript ="true"  />
        </tr>
    </table>
    </form>
</body>
</html>

Reference: Validation Controls in Asp.Net

Validation Controls in Asp.Net