call parent page from user control to invoke page methods

To illustrate how we will accomplish this using Reflections, we will be using repeater in a user control within a page.

Your repeater loads data easily within the user control code behind, but you want to utilize the “ItemCommand” event of the repeater to update some values on the page page.

Here’s how this can work:

Parent Page:

//the name doesn't have to match the corresponding method on user control but makes code more readable
    public void rptRepeaterName_ItemCommand(object sender, RepeaterCommandEventArgs e)
    {

        try
        {
            if (e.CommandName == "commandname")
            {
               //do some work on data then call update on parent page to reload data and show within a modal

                ParentPage_UpdatePanel.Update();
                ParentPage_ModalPopup.Show();

            }
        }
        catch (Exception ex)
        { 
//do something
            throw new ApplicationException(ex.ToString());
        }

    }

User Control:

    protected void rptRepeaterName_ItemCommand(object sender, RepeaterCommandEventArgs e)
    {
        MethodInfo mi = this.Page.GetType().GetMethod("rptRepeaterName_ItemCommand", BindingFlags.Public | BindingFlags.Instance);

//note we specify parent page as the object and pass in a new object representing our repeater and carrying its parameters
        if (mi!=null) mi.Invoke(this.Page, new Object[] {sender,e });

    }

Voila! Behold the power of Reflections! 8)

In particular, one of the references below (thanks Bruce Barker!) helped me come to this answer, however, the exact code he presents will result in a “Non-static method requires a target” error.

To avoid this error, make sure you always pass in the object when invoking a method that is non-static (within a class that is instantiated).

To learn more about reflections and how it works search my blog for other examples, and visit MSDN for a good overview.

References
Velocity Reviews, http://www.velocityreviews.com/forums/t71075-invoke-methods-on-the-parent-page-from-the-user-control.html
Reflection Overview (MSDN), http://msdn.microsoft.com/en-us/library/f7ykdhsy%28v=vs.71%29.aspx

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About Ronnie Diaz

Ronnie Diaz is an enterprise software engineer responsible for front-end and back-end development for companies in many industries. Heavily involved in cloud development, online retail, e-commerce and electronic ordering, fulfillment and customer relational systems.

Posted on July 15, 2011, in Programming & Development and tagged , , , , , , , , , , , , , , , . Bookmark the permalink. 1 Comment.

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