Calling a method in parent page from user control

Question

I\'ve a user control registered in an aspx page On click event of a button in the user control, how do i call a method which is there in the parent page\'s code

Answer 1

I love Stephen M. Redd's answer and had to convert it to VB. Sharing it here. Suggested edits welcome.

In the user control's code-behind:

Public Class MyUserControl
    Inherits System.Web.UI.UserControl

    'expose the event publicly
    Public Event UserControlButtonClicked As EventHandler 

    'a method to raise the publicly exposed event
    Private Sub OnUserControlButtonClick()

        RaiseEvent UserControlButtonClicked(Me, EventArgs.Empty)

    End Sub

    Protected Sub lbtnApplyChanges_Click(sender As Object, e As EventArgs) Handles lbtnApplyChanges.Click

        'add code to run here, then extend this code by firing off this event
        'so it will trigger the public event handler from the parent page, 
        'and the parent page can hanlde it

        OnUserControlButtonClick()

    End Sub

End Class

In the parent page subscribe to the event, so when the event is raised, your code will run here.

Public Class SalesRecord
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        'hook up event handler for exposed user control event to handle this
        AddHandler MyUserControl.UserControlButtonClicked, AddressOf MyUserControl_UserControlButtonClicked

    End Sub

    ''' <summary>
    ''' code to run when user clicks 'lbtnApplyChanges' on the user control
    ''' </summary>

    Private Sub MyUserControl_UserControlButtonClicked()

        'this code will now fire when lbtnApplyChanges_Click executes

    End Sub

End Class

Answer 2

Here is the classic example using events as suggested by Freddy Rios (C# from a web application project). This assumes that you want to use an existing delegate rather than make your own and you aren't passing anything specific to the parent page by event args.

In the user control's code-behind (adapt as necessary if not using code-behind or C#):

public partial class MyUserControl : System.Web.UI.UserControl
{
    public event EventHandler UserControlButtonClicked;

    private void OnUserControlButtonClick()
    {
        if (UserControlButtonClicked != null)
        {
            UserControlButtonClicked(this, EventArgs.Empty);
        }
    }

    protected void TheButton_Click(object sender, EventArgs e)
    {
        // .... do stuff then fire off the event
        OnUserControlButtonClick();
    }

    // .... other code for the user control beyond this point
}

In the page itself you subscribe to the event with something like this:

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        // hook up event handler for exposed user control event
        MyUserControl.UserControlButtonClicked += new  
                    EventHandler(MyUserControl_UserControlButtonClicked);
    }
    private void MyUserControl_UserControlButtonClicked(object sender, EventArgs e)
    {
        // ... do something when event is fired
    }

}

Answer 3

Scott Allen has a useful article on event bubbling from a user control to the parent page, which elaborates on the answer provided by Stephen M. Redd:

• Event Bubbling From Web User Controls in ASP.NET (C#)

Answer 4

I suggest you don't call the page method directly, as you would be tying your control to the specific page.

Instead expose an event, and have the page subscribe to it. It works for any number of pages, can more easily be used when the control is multiple times on a single page (perhaps even on a list) and is more in line with asp.control design.

Answer 5

You can use Session . Say when you click on a button in user control and when you want to call Parent page method then in event handler of button click set value as

Session["CallParent"]="someValue";

as button will post back the page . On Page_Load event of Parent Page add it

protected void Page_Load(object sender,EventArgs e)
{
   if(Session["CallParent"]!=null)
   {
      // here call the Parent Page method 
      Method1();
      // now make the session value null
     Session["CallParent"]=null;
    }
}

It is much more efficient

Answer 6

I posted something that works here: Access control > page > master nested > master

Or if you want access to a control you can also do this:

Update parent page Where parent has an update panel named "UpdatePanel1"

Control

UpdatePanel onParent1 = (UpdatePanel)Parent.FindControl("UpdatePanel1");
onParent1.Update();