CODEWITHSUNDEEP
asp.netinheritanceuser-controls
David Fox
David Fox

Reputation: 10753

Control cannot override Page_Load in hierarchy

A ChildClass user control I'm working with has a chain of parent classes, ultimately inheriting from System.Web.UI.UserControl.

public BasestClass : AnotherClassExtendingUserControl
{
    private void Page_Load(object sender, EventArgs e)
    {
        // do some stuff
    }
}

public BaseClass : BasestClass
{
    // no Page_Load
}

Two parent classes up the chain, Page_Load is marked private. The 'middle' class obviously doesn't override it, but I need to add something to the Page_Load of the ChildClass user control.

public ChildClass : BaseClass
{
    // think I need to override Page_Load here,
    // but there is no acceptable method to override
}

What can I do to get into the Page_Load of ChildClass? There are controls in that control that I need to manipulate that do not exist in BaseClass or BasestClass.

Upvotes: 2

Views: 1520

Answers (2)

James Johnson
James Johnson

Reputation: 46067

The Page_Load (or Load) event gets raised during execution of the OnLoad event method, so I would suggest moving your logic there. You shouldn't have a problem overriding the OnLoad method from your child class.

Upvotes: 2

mafue
mafue

Reputation: 1878

I copied your classes and just changed two things:

BasestClass : System.Web.UI.UserControl

That shouldn't alter anything, since you said that BasestClass ultimately inherits from UserControl.

I also added this to BasestClass.Page_Load:

Response.Write("BasePage_Load");

Now, to solve your problem:

You can add a constructor to ChildClass and add an event handler for the Load event.

public ChildClass()
{
        Load += new EventHandler(_Default_Load);
}

void _Default_Load(object sender, EventArgs e)
{
        Response.Write("Event Handler");
}

You can also override OnPreRender:

protected override void OnPreRender(EventArgs e)
{
       base.OnPreRender(e);
       Response.Write("OnPreRender");
}

Doing all of the above, this is output in the response:

Event Handler
BasePage_Load
OnPreRender

If you want to be sure that the Page_Load method of BasestClass has already run before your new code, OnPreRender is the place to do your thing.

Upvotes: 1

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