ASP.NET Web Forms Web Forms Server Controls Web Forms User Controls
User controls only work when they are included in a Web Forms page. When a request arrives for a page and that page contains a user control, the user control goes through all of the Web Forms Page Processing Stages that any server control is subject to.
Including a user control in a Web Forms page is simple.
- In the containing Web Forms page, declare an @ Register directive that includes:
- a tagPrefix attribute, which associates a prefix with the user control. This prefix will be included in opening tag of the user control element.
- A tagName attribute, which associates a name with the user control. This name will be included in the opening tag of the user control element.
- A Src attribute, with defines the virtual path to the user control file that you are including in the Web Forms page.
For example, the following code registers a user control defined in the file Login.ascx. It has been given the tag prefix myCtrls and the tag name Login. The file is located in a subdirectory named Controls.
<%@ Register tagPrefix="myCtrls" tagName="Login" src=".\controls\login.ascx" %>
- Using custom server control syntax, declare the user control element between the opening and closing tags of an HtmlForm server control ( <
form runat=server></form> ) . For example, to declare the control imported in the previous step, use the following syntax.
<html>
<body>
<form runat="server">
<myCtrls:Login id="myLogin" runat="server"/>
</form>
</body>
</html>
NOTE: Regardless of how many ASP.NET server controls ( user controls and any others ) you include on your Web Forms page, you should include only one HtmlForm server control on a Web Forms page. Include all server controls between the opening and closing tags of this control.
Creating a User Control Defining Web Forms Event-Handling Methods Handling User Control Events