ASP.NET Event Delegation Delegation of Event from User Control to aspx
Example
Normally, we opt this approach if we want complete encapsulation and don't want to make our methods public.
Ascx
<div style="width: 100%;">
<asp:Button ID="btnAdd" runat="server"
Text="Add" OnClick="btnAdd_Click"></asp:button>
<asp:button id="btnEdit" runat="server"
text="Edit" onclick="btnEdit_Click"> </asp:button>
<asp:button id="btnDelete" runat="server"
text="Delete" onclick="btnDelete_Click"> </asp:Button>
<asp:button id="btnReset" runat="server"
text="Reset" onclick="btnReset_Click"></asp:button>
</div>
Ascx.cs
public delegate void ActionClick();
public partial class EventDelegation : System.Web.UI.UserControl
{
public event ActionClick OnAddClick;
public event ActionClick OnDeleteClick;
public event ActionClick OnEditClick;
public event ActionClick OnResetClick;
protected void btnAdd_Click(object sender, EventArgs e)
{
if(OnAddClick!= null)
{
OnAddClick();
}
}
protected void btnEdit_Click(object sender, EventArgs e)
{
if (OnEditClick != null)
{
OnEditClick();
}
}
protected void btnDelete_Click(object sender, EventArgs e)
{
if(OnDeleteClick!= null)
{
OnDeleteClick();
}
}
protected void btnReset_Click(object sender, EventArgs e)
{
if(OnResetClick!= null)
{
OnResetClick();
}
}
}
The user control specifies some public events like OnAddClick, OnEditClick,etc., which declare a delegate. Anyone who wants to use these events needs to add the EventHandler to execute when the corresponding button click event occurs.
Aspx Design
<%@ Register src="Controls/EventDelegation.ascx"
tagname="EventDelegation" tagprefix="uc1" %>
<!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>
<uc1:Direct ID="Direct1" runat="server" />
</div>
</form>
</body>
</html>
Aspx.cs
public partial class EventDelegation : System.Web.UI.Page
{
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
ActionControl.OnAddClick += ActionControl_OnAddClick;
ActionControl.OnDeleteClick += ActionControl_OnDeleteClick;
ActionControl.OnEditClick += ActionControl_OnEditClick;
ActionControl.OnResetClick += ActionControl_OnResetClick;
}
private void ActionControl_OnResetClick()
{
Response.Write("Reset done.");
}
private void ActionControl_OnEditClick()
{
Response.Write("Updated.");
}
private void ActionControl_OnDeleteClick()
{
Response.Write("Deleted.");
}
private void ActionControl_OnAddClick()
{
Response.Write("Added.");
}
}
