Use delegate by below way.
n ASP.Net, we develop custom user control as
a reusable server control independent of any containing parent aspx page. User
control has its own public properties, methods, delegates, etc that can be used
by parent aspx page. When a user control is embedded or loaded into a page, the
page can access
In ASP.Net, we develop custom user
control as a reusable server control independent of any containing parent aspx
page. User control has its own public properties, methods, delegates, etc that
can be used by parent aspx page. When a user control is embedded or loaded into
a page, the page can access public properties, methods, delegates, etc that are
in user control. After loading the user control, there a situation may arise
like calling methods in page itself. But when a user control is developed, it
has no knowledge of containing page. So it becomes a trick to call the page
method.
In .Net, Delegate class has one
method DynamicInvoke.
DynamicInvoke method is used to invoke (late-bound) method referenced by
delegate. We can use this method to call a method in parent page from user
control. Let’s try with this example.
First create a user control called
CustomUserCtrl. Its code will look some thing like this:
public partial class CustomUserCtrl : System.Web.UI.UserControl
{
private System.Delegate _delWithParam;
public Delegate PageMethodWithParamRef
{
set {
_delWithParam = value; }
}
private System.Delegate _delNoParam;
public Delegate PageMethodWithNoParamRef
{
set {
_delNoParam = value; }
}
protected void Page_Load(object sender, EventArgs e)
{
}
protected void BtnMethodWithParam_Click(object sender,
System.EventArgs e)
{
//Parameter to a method is
being made ready
object[] obj = new object[1];
obj[0] = “Parameter Value” as object;
_delWithParam.DynamicInvoke(obj);
}
protected void BtnMethowWithoutParam_Click(object sender,
System.EventArgs e)
{
//Invoke a method with no
parameter
_delNoParam.DynamicInvoke();
}
}
Then add this user control into an
aspx page. The code behind of this page is as:
public partial class _Default : System.Web.UI.Page
{
delegate void DelMethodWithParam(string strParam);
delegate void DelMethodWithoutParam();
protected void Page_Load(object sender, EventArgs e)
{
DelMethodWithParam
delParam = new DelMethodWithParam(MethodWithParam);
//Set method reference to a
user control delegate
this.UserCtrl.PageMethodWithParamRef = delParam;
DelMethodWithoutParam
delNoParam = new DelMethodWithoutParam(MethodWithNoParam);
//Set method reference to a
user control delegate
this.UserCtrl.PageMethodWithNoParamRef = delNoParam;
}
private void MethodWithParam(string strParam)
{
Response.Write(“<br/>It
has parameter: ” + strParam);
}
private void MethodWithNoParam()
{
Response.Write(“<br/>It
has no parameter.”);
}
}
BtnMethodWithParam and
BtnMethowWithoutParam are two different buttons on the user control that are
invoking the methods in the parent page. On Page_Load of the page, we are
setting the references of page class methods to delegate type properties in the
user control. Click different buttons of user control, you will see
MethodWithParam(string strParam) and MethodWithNoParam() methods called.
This is all we have to do to call
page class methods from user control in ASP.Net.
