Custom Controls in ASP.net

Custom Control in ASP.net
• Name : Kunj Desai
• Enrollment no.:140950107022
• Branch: CSE-A
• Semester: 6th
• Year : 2017

• Custom controls are deployed as individual assemblies. They are
compiled into a Dynamic Link Library DLL and used as any other
ASP.NET server control. They could be created in either of the
following way:
1. By deriving a custom control from an existing control.
2. By composing a new custom control combing two or more
existing controls.
3. By deriving from the base control class.

• To understand the concept, let us create a custom control, which will
simply render a text message on the browser. To create this control,
take the following steps:
• Create a new website. Right click the solution nottheproject at the top
of the tree in the Solution Explorer.

• In the New Project dialog box, select ASP.NET Server Control from the project
templates.
• The above step adds a new project and creates a complete custom control to the
solution, called
• ServerControl1. In this example, let us name the project Custom Controls. To use
this control, this must be added as a reference to the web site before registering it
on a page.

• To add a reference to the existing project, right click on the project
notthesolution, and click Add Reference. To add a reference to the
existing project, right click on the project notthesolution, and click Add
Reference.
• Select the Custom Controls project from the Projects tab of the Add
Reference dialog box. The Solution Explorer should show the
reference.

• To use the control on a page, add the Register directive just below the @Page directive:
<%@ Register Assembly="Custom Controls" Namespace ="Custom
Controls" TagPrefix="ccs" %>
• Further, you can use the control, similar to any other controls.
<form >
<div>
<ccs:ServerControl1 runat="server" Text = "I am a Custom Server
Control" />
</div>
</form >

• When executed, the Text property of the control is rendered on the
browser as shown:
• In the previous example, the value for the Text property of the custom
control was set. ASP.NET added this property by default, when the
control was created.

• The above code is automatically generated for a custom control.
Events and methods could be added to the custom control class.
 Example:
• Let us expand the previous custom control named SeverControl1. Let
us give it a method named checkpalindrome, which gives it a power to
check for palindromes.
• Palindromes are words/literals that spell the same when reversed. For
example, Malayalam, madam, saras, etc.

• When you change the code for the control, you must build the solution by clicking
Build --> Build Solution, so that the changes are reflected in your project. Add a text
box and a button control to the page, so that the user can provide a text, it is checked
for palindrome, when the button is clicked.
 Form:
<form id="form1" runat="server">
<div> Enter a word: <br />
<asp:TextBox ID="TextBox1" runat="server" style="width:198px"> </asp:TextBox>
<br /> <br />
<asp:Button ID="Button1" runat="server onclick="Button1_Click" Text="Check
Palindrome" style="width:132px" /> <br /> <br /> <ccs:ServerControl1
ID="ServerControl11" runat="server" Text = "" />
</div>
</form>

• The Click event handler for the button simply copies the text from the
text box to the text property of the custom control as shown below:
protected void Button1_Click(object sender, EventArgs e)
{
this.ServerControl11.Text = this.TextBox1.Text;
}
• When executed, the control successfully checks palindromes.

 Observe the following:
1. When you add a reference to the custom control, it is added to the toolbox and you
can directly use it from the toolbox similar to any other control.
2. The Render Contents method of the custom control class is overridden here, as
you can add your own methods and events.
3. The Render Contents method takes a parameter of HtmlTextWriter type, which is
responsible for

Custom Controls in ASP.net

More Related Content

What's hot (20)

Similar to Custom Controls in ASP.net (20)

More from kunj desai (9)

Recently uploaded (20)

Custom Controls in ASP.net