Question

I’ve got the following DropDownList in my code that is firing in the wrong order:

public class MyWebpart : WebPart
{
    private DropDownList dropDown = new DropDownList();

    private string selectedValue;

    public Webpart()
    {
    }

    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        dropDown.AutoPostBack = true;
        dropDown.SelectedIndexChanged += new EventHandler(DropDown_SelectedIndexChanged);
    }

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        this.EnsureChildControls();
    }

    protected void DropDown_SelectedIndexChanged(Object sender, EventArgs e)
    {
        selectedValue - dropDown.SelectedValue;
    }

    protected void override void CreateChildControls()
    {
        base.CreateChildControls();
        // create some stuff here
    }

I was expecting when the drop down selection changes, the DropDown_SelectedIndexChanged will get called first, but instead it went through the entire lifecycle going from OnInit, OnLoad, CreateChildControls, then DropDown_SelectedIndexChanged.

Am I missing something? How can I get DropDown_SelectedIndexChanged call first?

Answer 1

You can’t change the page lifecycle. What you can do is either check if Page.IsPostBack and do something appropriate only on first load OR you can create a webservice and call that webservice from javascript to execute your selectedindexchanged actions in js rather than posting back the whole page.

Good luck!