C# - Event Handler In Masterpage Accessing Controls In The Client Page?

I have a button on a masterpage, which when clicked, calls a method that takes an EventHandler previously saved to the viewstate, this method is on the client page, and executes it:

protected void Save_Click(object sender, EventArgs e)
{
this.SaveButtonEvent += (EventHandler)ViewState["saveEvent"];
if (this.SaveButtonEvent != null)
{
this.SaveButtonEvent(sender, e);
}
}

This then calls a very simple method on the client page:

protected void Button2_Click(object sender, EventArgs e)
{
Label1.Text = TextBox2.Text;
}

However, the value of TextBox2 is incorrect, it is the value of the text box that was set when the page loaded (or if any other item on the pages changes it), the new value is not passed.

If I add a button to the client page, that calls the Button2_Click event directly, it get's the correct value.

Is the reason I am not getting the correct value of the text box because the Event is called from the master page?

I should add, that this button is created dynamically, and the event delegate will vary, which is why I have to set it at run time. I need a way to set the delegate on a click, and persist this until it is changed again.