Calling a function before Page_Load

Question

I have a button that calls function A()

When I click on it I want the calls to be made in that order:

A()
Page_Load()

Right now it's doing:

Page_Load()
A()

Is there a way around that or is it just by design and there's nothing I can do about it?

Answer 1

The easiest way to do this would be to use a HTML Submit button and check to see if it is in the Form on every postback in Page_Init

public void Page_Init(object o, EventArgs e)
{
     if(!string.IsNullOrEmpty(Request.Form["MyButtonName"]))
     {
          A();
     }
}

And in your ASP.NET code:

<Button Type="Submit" Name="MyButtonName" Value="Press Here To Do Stuff Early!" />

I think that will work.

Answer 2

Control events (such as the click events of buttons) are called after page_load. The controls are not guarenteed to be fully initialized prior to page_load. If you really need to call a function before page_load has been called based on whether a button has been pressed you'll have to examine the request to check if the button has been pressed (basically old school ASP)

Answer 3

You need to call your function in the Page_Init. Page_Init will happen before Page_Load.

Here's an Overview of the ASP.NET Page Lifecycle.

Answer 4

Not exactly: ASP.NET will always call Page_Load before handling postback events like Button_Click.

However, you can accomplish what you want by redirecting to your page after handling the postback event. (Using the Post-Redirect-Get pattern.)

Inside your Page_Load method, you can avoid running any relevant code twice by checking to see if it's a postback first:

if (!this.IsPostBack) {
    // Do something resource-intensive that you only want to do on GETs
}

Answer 5

As Jeff Sternal answered, The Post-Redirect-Get pattern is a good way of solving a problem like this.

In my circumstances i had a calendar and if you clicked a date it would add that to a scheduler. The scheduler would have buttons on each new date that needed to have onclick functions tied to them.

Because the new row was being added with a linkbutton(on the calendar), in the code the new scheduler date was being added at the Postback event handling meaning that the new set of buttons wouldn't have a command tied to them.

The page life Cycle

Post Get Redirect

Answer 6

I don't think it's possible, at least, not in the way described by your question. When you click a button it will send a request to the server which in turn will start processing it, and follow the ASP.NET Page Lifecycle as posted by Joseph.

Alternatively you could try making an AJAX call to a page without reloading the current one you're on and do whatever processing you require.