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MDI Child & Key Preview...

Hi...

I need to catch, for example, a Ctrl+A key press on a form.
Usually I set the KeyPreview to true and handle the KeyDown Event... no problem.

Now I need to do this on an MDIChild form but the KeyDown event just doesn't fire.
Although it does fire on the MDI Parent.

Is there a way to work this out?

Thanks,
Alex
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Alexandre Simões
Asked:
Alexandre Simões
1 Solution
 
AlexFMCommented:
Handle keyboard event in MDI parent and call functions of MDI child using ActiveMdiChild propertty.
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Alexandre SimõesManager / Technology SpecialistAuthor Commented:
Hi... Thanks for the reply...
That is not an option on my scenario.
This MDIParent holds 16 different projects that have an overall of 1000+ Forms...
It's not "doable" to hadle each case on the MDIParent...

Although that gave me a great idea...
I can create and Interface, implement it on the child forms, validate on the MDIParent KeyDown Event if there's an active MDIChild and if so if it also implements my Interface then finally if everything is true, call the method on the MDI Active Child.

Great!!
Thanks for putting my head to work...
Alex
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Bob LearnedCommented:
I did a small test with two forms, and this is what I discovered:

1) Parent has KeyPreview = True
2) Child has KeyPreview = True
3) Child Form_KeyPress:

    private void OnFormKeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
    {
       this.textBox1.AppendText(e.KeyChar);
      e.Handled = true;
    }

4) Parent Form_KeyPress:

    private void OnFormKeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
    {
       MessageBox.Show(e.KeyChar);
    }

5) Without the e.Handled = true in the child handler, the message would flow up to the parent, and I would get a message box.  With it I don't.

Bob
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Alexandre SimõesManager / Technology SpecialistAuthor Commented:
I Bob...

I tried that but couldn't reproduce the behavior you said.
I tried some combinations with the KeyPreview set to true and false between MDI parent and child and nothing.

If I use the KeyPressEvent instead of the KeyDown I lose some informations on the eventargs and still the parent gets called.
It gets called before the child form...

Can you describe the configurations you use the get that behavior?

Thanks!
Alex
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Bob LearnedCommented:
Alex,

Here is a different test, with different code, and I am hoping for a better result:

Form1 (parent):

  KeyPreview = true;

  private void Form1_Load(object sender, System.EventArgs e)
  {

    this.IsMdiContainer = true;

    Form2 f = new Form2();
    f.MdiParent = this;
    f.Show();

  }

  private void Form1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
  {
    if (this.ActiveMdiChild == null)
      MessageBox.Show("Form1 key down");
  }

Form2 (child):

  private void Form2_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
  {
    MessageBox.Show("Form2 key down");
    e.Handled = true;
  }

Test #1:
   Run this code:  Get 'Form2 key down'

Test #2:
   Comment out 'f.Show();'.  Get 'Form1 key down'.

Bob
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Alexandre SimõesManager / Technology SpecialistAuthor Commented:
Hi...
Thanks Bob... that worked but... :)

They came with some new ideas...
We use MenuStrips on both child and parent, and assign shortcut keys to them.
If the same shortcut exists on both parent and child, the child event will never raise...

Any ideas?!

Many thanks!
Alex
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Bob LearnedCommented:
Can you show me what the menus look like?  I bet you can't assign unique shortcut keys to the menu items, right?  That one doesn't sound quite so easy ;)

Bob
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Alexandre SimõesManager / Technology SpecialistAuthor Commented:
I can't show you but I can guide you to reproduce my scenario.

Scenario:
1- Create 2 Forms, one MDIParent and one MDIChild
2- Add a MenuStrip to both
3- Add one MenuItem on both
4- Set the same ShortcutKey on both MenuItems (use the ShortcutKey property on the Menu item)
5- Add a messagebox to the MenuItemsClick so you can identify whitch was called

Test:
Having both forms visible (MDIParent with the MDIChild on it), try to use the shortcut key to trigger the MDIChild MenuItem.

Result:
The MDIParent is the one that allways gets called!!



Thanks!
Alex
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Bob LearnedCommented:
Alex,
That is a significantly more difficult proposition.  I haven't found a solution yet.

Bob
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Alexandre SimõesManager / Technology SpecialistAuthor Commented:

The MDI structure itself is very limitted...
I think this is one more thing that is just no ment to be done.

As this is a Fox upgrade, we had some other things that had to be left behind an dsome others that we had to do strange
|stupid things to accomplish (some good examples are simply desable tab pages... and a lot of stuff related to the DataGridView).

Many thanks Bob,
Alex
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Bob LearnedCommented:
BTW, here is my failed attempt:

    private void TestToolStripMenuItem_Click(object sender, EventArgs e)
    {

        int shortCutValue = (int)((ToolStripMenuItem)sender).ShortcutKeys;

        if (this.ActiveMdiChild != null)
        {
            foreach (Control ctl in this.ActiveMdiChild.Controls)
            {
                if (ctl.GetType() == typeof(MenuStrip))
{
                    MenuStrip strip = (MenuStrip)ctl;
                    foreach (ToolStripItem item in strip.Items)
                    {
                        if (item.GetType() == typeof(ToolStripMenuItem) && ((int)((ToolStripMenuItem)item).ShortcutKeys) == shortCutValue)
                        {
                            return;
                        }
                    }
                }
            }
        }
        MessageBox.Show("Main form");
     }

Bob
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CarlVerretCommented:
I had the same kind of problem (shortcut in mdimain and client form with same key)  with VB.net 2005.  

I haven't found any solution yet.
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