Validation Controls in Asp.Net
Validations with asp.net page
1)ensuring proper entry of data from user is called “validation”
Ex: name cannot be blank
Mobile number should be 10 digits
2)asp.net provides validation controls with built in logic to validate user input
3)validation controls will support client side validation (or) server side validation. This makes developer job easier and faster.
Asp.net is providing following validation controls
1)range validation
2)required field validator
3)compare validator
4)regular expression validator
5)custom validator
6)validation summary
Common properties of validation controls
1)control validate
Specify stand webserver controlid to validate user input
2)text
Specify error information to be displayed if user is providing an invalid input
3)error message
Specify error information to be displayed with validation summary control user is providing an invalid input
4)set focus on error-true/false
True-the cursor will be placed in the same textbox if user input is invalid, If user input is valid then cursor will be placed in the next textbox
False[default]-cursor will be placed in the next textbox irrespective of user input valid (or) invalid
5)enable client script-true/false
True[default]-client side validation
False-server side validation
Range validator
->this control can be used to validate user input within required range(specified range)
->properties
1)minimum value-specify lower bound
2)maximum value-specify upper bound
Example on range validator
Goto visual studio
Start->run->devenv
It will display main window of visual studio
File menu->new->website->visual c#->select asp.net empty website
Weblocation->e:\aspnet\validationsite[drive:\dir\websitename]
Visual studio create a folder with website name, in this folder website related files will be placed
Add webform
Goto view menu and select solution explorer
Right click on website path and select add new item
Select webform
Give name as default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" 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>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
Goto design part design the form like below
Age[label1]
Mobilenumber[label2] rangevalidator1
|
submit |
->rangevalidator1 available in toolbox->validation
Rangevalidator1 properties
Controlto validate-textbox1
Minimum value-25
Maximum value-40
Text-invalid age
Backcolor-select red
Forecolor-select white
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
Response.Write("<h2>submitted </h2>");
}
}
Goto contrl f5
Note:
1)valiation control will download javascript to browser, this javascript will be executed to validate user input into textbox when cursor is leaving textbox
2)button click will not perform webpage submission if page validations are not successful
3)till asp.net 2.0 javascript logic used by validation controls will be visible to developer in the form of jsfile, later versions doesn’t provide jsfile to developer
4)a single validation control can validate only one standard webserver control[textbox]
5)a single standard webserver control[textbox] can be binded with more than one validations control
6)range validator will validate textbox if input is given, If textbox is blank then it will not perform validation
7)requiredfieldvalidator can be used to validate whether textbox is given with input (or) not
8)in the above example age textbox requires 2 validation control [requiredfieldvalidator and rangevalidator]
Example on requiredfieldvalidator1
Goto visual studio
Start->run->devenv
It will display main window of visual studio
File menu->new->website->visual c#->select asp.net empty website
Weblocation->e:\aspnet\validationsite[drive:\dir\websitename]
Visual studio create a folder with website name, in this folder website related files will be placed
Add webform
Goto view menu and select solution explorer
Right click on website path and select add new item
Select webform
Give name as default.aspx
Goto design part design the form like below
Age[label1]
Mobilenumber[label2] rangevalidator1 requiredfieldvalidator
|
submit |
Requiredfieldvalidator properties
Controltovalidate-textbox1
Text-enterage
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
TextBox1.Attributes.Add("onblur", "validatorvalidate(" + RequiredFieldValidator1.ClientID + ")");
}
}
Goto contrl f5
Note:
1)by default requiredfieldvalidator will validate textbox for button click this can be changed to textbox loosing focus by executing following statement
Ex:textbox1.attributes.add(..)
2)by default validation control will occupy space with in webpage irrespective of validation is failed or not this can be changed using display property.
