CODEWITHSUNDEEP
c#.netwinformsresizewindowstate
user1283610
user1283610

Reputation: 116

Setting WindowState to Maximized causes window to appear too early

I read that the Load event is supposed to be fired after the window handle has been created, but before the window actually become visible. For the most part, this seems to be true. However, I've found that when I create a form with the WindowState property set to FormWindowState.Maximized (either via the VS designer, or programatically in the constructor), the window becomes visible prior to the Load event firing. For example:

using System;
using System.Windows.Forms;

namespace MyApplication
{
    public partial class MyForm : Form
    {
        public MyForm()
        {
            InitializeComponent();
            WindowState = FormWindowState.Maximized;
        }

        protected override void OnLoad(EventArgs e)
        {
            MessageBox.Show("OnLoad - notice that the window is already visible"); 
            base.OnLoad(e);
        }
    }
}

This in turn causes the displayed form to flicker a lot while its controls (which are laid out during the Form.Load event) are resized while the window is visible. If I did not set the state to be maximized, then all the resizing is done before the window is shown (which is what I would have expected).

I could hold off on setting the WindowState until the end of the Load event, but that still causes a lot of flickering because the window becomes visible and then all of the controls resize.

Any thoughts?

Upvotes: 8

Views: 10917

Answers (4)

Vinicius Gonçalves
Vinicius Gonçalves

Reputation: 2724

You have to set WindowState BEFORE InitializeComponent():

    public Form() //Constructor
    {
        WindowState = FormWindowState.Maximized;

        InitializeComponent();
    }

Upvotes: 2

jramos
jramos

Reputation: 128

Try to delay the change of WindowState until the first Activated event firing. This works for me in VB.NET with VS2005 and framework 2.0.

Upvotes: 2

Steve
Steve

Reputation: 216323

If you need to put some diagnostic message in the Load event use System.Diagnostics.Debug.WriteLine();
If you use MessageBox, you will destroy the normal flow order of events.

protected override void OnLoad(EventArgs e)         
{             
     System.Diagnostics.Debug.WriteLine("onLoad");              
     base.OnLoad(e);         
}

This post explain more details

Upvotes: 1

Sam Axe
Sam Axe

Reputation: 33738

Things that change the appearance of the window (resizing for instance) cause the window to become visible.

You could call .Hide() or .Visible = False in your ctor and make it visible again at the end of .Load

Upvotes: 0

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