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I am working on Mdiforms, I took menustrip with one menustrip item(parent form), in that i took 3 child forms. when I open child forms those forms fit into parent form(child form maximize window). when i open childforms and close those child forms one by one there is no problem, all forms are maximized window size.

When i open no.of childforms, the last childform is minimized the remaining childforms(before open last childforms) are goes to normal window size(not in maximum window size).

How to maximize Child windows, not only childforms closing, even childforms minimized also(all child forms are maximized only even closed or minimized).
Updated 27-Dec-11 21:48pm

1 solution

You can for example create a helper class which would notify the child windows that some form has been minimized. For example something like the following.

public static class Helper {
    public static System.EventHandler SomeoneGotMinimized;

    public static void RaiseTheEvent() {
        if (SomeoneGotMinimized != null) {
            SomeoneGotMinimized(null, new EventArgs());

And in the child forms
public partial class Form1 : Form {
    public Form1() {

        Helper.SomeoneGotMinimized += new EventHandler(this.HandleMinimization);


    private void Form1_Resize(object sender, EventArgs e) {
        if (this.WindowState == FormWindowState.Minimized) {
    private void HandleMinimization(object sender, EventArgs e) {
        if (this.WindowState == FormWindowState.Normal) {
            this.WindowState = FormWindowState.Maximized;

That's just a quick sketch so modify it based on your needs.

Note: this sounds like you're trying to emulate the SDI functionality so consider using SDI instead of MDI in your design. MDI is kind of 'abandoned' technique and is replaced by newer design guidelines.
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