Create Custom Web Control in ASP. NET

Sapna

Custom ControlASP.NET custom controlText Box ControlWeb Custom Control

12 Comments

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Bhuvan Pandey10y ago
Hi Sapna. Thanks to share this article. But I try to execute the same code but code is not working. Even I don't know, how to pass "TextBox would not empty" error message.
Vipul Malhotra11y ago
Nice article..Thanks for sharing
FAROOKH MANSURI11y ago
Hi Sapna , It's nice article...
Vishnu Bhangale11y ago
sir it give me an error like Control 'ServerControl1' referenced by the ControlToValidate property of '' cannot be validated
vilas jadhav12y ago
code is not working ...please send me working code
Rajkumar Palnati13y ago
Hi, Very Good Example.. I have created it as same the thing is problem at "protected override void On_Init(EventArgs e)" and later i correted that now i'm not getting any validation message pls send me detailed information about this on [email protected] Thanks in Advance
Santosh Yadav13y ago
very nice article.. Thanks.
nguyen DC13y ago
Hi, Sapna. I have created a question here: http://www.c-sharpcorner.com/forums/thread/201763/how-to-create-many-tags-in-one-tag-using-webcontrol-in-asp.aspx Please help me if pleasure, thanks so much.
nguyen DC13y agoedited
Hi, Sapna. I want to create a webcontrol with result like below: <myControls:MyGraph id="myGraph1" runat="server"> <Colors> <myControls:ColorD Value="#abcdef" /> <myControls:Color> Blue </myControls:Color> <myControls:ColorD Value="#1ad234" /> <myControls:ColorD Value="#123456" /> </Colors> </myControls:MyGraph> and I want to know the order of them too.May you help me about this? Thanks and best regards, Nguyen DC
amir sajjadi13y ago
THANK YOU. NOT WORK IN VB.NET !!!
Anil Kumar15y ago
Nice One...
- Sapna15y ago
  Thank You Anil............

Introduction:

Now we are going to discuss about how to create a custom web control in ASP.NET. How do we create and use them in ASP.NET web site application? As we know, a custom control is a control made by the user for a specific purpose and later we can use it in our application. In this article we are going to see how we can create and implement a custom web control. Now we are going to make a required valid Textbox value which checks that the Text box has the value or not, if not then it will give an error that it cannot not be empty. This web control will inherit from the Textbox web control, and will automatically add a required field validator at run-time. We will just define an Instance of the required field validator.

Let see how we create and use it:

Step 1: Now create a web server control application

First go to File->New->Project->ASP.NET Server Control
Name it as Valid Text box

Step 2: Code of the Class to validate the Textbox's Text

Code :
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace ValidTextBox
{
[DefaultProperty("ch")]
[ToolboxData("<{0}:ValidTextBox1 runat=server></{0}:ValidTextBox1>")]
public class ValidTextBox1 : TextBox
{
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
public string ch
{
get
{
String s = (String)ViewState["ch"];
return ((s == null) ? "[" + this.ID + "]" : s);
}
set
{
ViewState["ch"] = value;
}
}
private RequiredFieldValidator rfv;
public string NotValid;
public string C_Script = "true";

protected override void On_Init(EventArgs e)
{
rfv = new RequiredFieldValidator();
rfv.ControlToValidate = this.ID;
rfv.ErrorMessage = this.NotValid;
rfv.EnableClientScript = (this.C_Script.ToLower() != "false");
Controls.Add(rfv);
}
protected override void RenderContents(HtmlTextWriter op)
{
op.Write(ch);
base.RenderContents(op);
rfv.RenderControl(op);
}
}
}

Code Description : Here we are using a class name ValidTextBox1 which inherits from the Textbox Class. In this class we have to make some methods like On_init() which shows how we create a instance of required field validator control. Now we see that the [DefaultProperty("ch")] which specify default attribute of the Control. Now we have to make the two property name as Not Valid and C_Script which are public and used to validate the text in the Text box and shows the script will be true. The [ToolboxData] specifies the format string for the element. The string becomes the control's markup when the control is double-clicked in the toolbox or dragged from the toolbox onto the design surface.

Step 3: Now we have to add a namespace and an assembly information to the AssemblyInfo.cs file.

Firstly you have to add a namespace at the top of the page named as System.Web.UI.
Secondly you have to write an assembly at the end of the page given below.

[assembly: TagPrefix("ValidTextBox","asp Sample")].