User Control: Event Handling using Delegates

UserControl Page :

public partial class ButtonCombo : System.Web.UI.UserControl

{
public delegate void OnButtonClick(string val);
public event OnButtonClick eventHandler;
protected void Page_Load(object sender, EventArgs e){
}

protected void Button1_Click(object sender, EventArgs e){


if (eventHandler != null)eventHandler(
"Add");
// var classname = eventHandler.Method.DeclaringType;Response.Write("Added");
// Response.Write("Added " + classname);//eventHandler = null;}
protected void Button2_Click(object sender, EventArgs e){

if (eventHandler != null)eventHandler(
"Update");Response.Write(
"updated");
//eventHandler = null;}
protected void Button3_Click(object sender, EventArgs e){

if (eventHandler != null)eventHandler(
"Delete");Response.Write(
"Deleted");
//eventHandler = null;}
}


In ASPX page, take two pages say, Default.aspx and Home.aspx :
Use this usercontrol in both the pages.
Default.aspx

.......
</head><
body><form id="form1" runat="server"><div>
<USC1:UserControl runat="server" ID="Direct" EnableTheming="True" />..........
..........
</div></form></
body></
html>

Code Behind :

public partial class _Default : System.Web.UI.Page {


protected void Page_Load(object sender, EventArgs e){

if(Page.IsPostBack)Direct.eventHandler +=
new ButtonCombo.OnButtonClick(Direct_eventHandler);
}


void Direct_eventHandler(string val){

//val = "Hello";//Label1.Text=val;Response.Write("Operation : " +val);

}
}

Similarly in HOME.ASPX, use this usercontrol and write the similar event:

Home.Aspx :

public partial class Home : System.Web.UI.Page{
protected void Page_Load(object sender, EventArgs e){

if (Page.IsPostBack)Usc1.eventHandler +=
new ButtonCombo.OnButtonClick(Direct_eventHandler);}

void Direct_eventHandler(string val){

//val = "Hello";//Label1.Text = val;Response.Write(val + "In new page");}

}

   The Output of the Default page:

The Output of the Home page:

Hence this way we can handle the events in different pages, using delegate events. If we have 10 pages using the same user control, we can write our own logic in the events for each page and call the events of the user control accordingly.