How to find control with focus?

[Peter Steele]

I have a form with four text fields, each with sequentially ordered
tabstops. I want to have the fields recognize the return key and
automatically shift the focus to the next control. I created the following
event handler that I've assigned to the KeyUp event of each of the TextBox
controls:

private void Any_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.Escape)
{
Close();
}
else if (e.KeyCode == Keys.Return)
{
foreach (Control c in this.Controls)
if (c.Focused) this.GetNextControl(c, true).Focus();
}
}

This works when the current control is the first text field, moving the
focus correctly to the second text field. However, when I hit enter in the
second text field, the focus moves to the fourth text field, skipping over
the third? What am I doing wrong here?

 

[Herfried K. Wagner [MVP]]

I have a form with four text fields, each with sequentially ordered
tabstops. I want to have the fields recognize the return key and
automatically shift the focus to the next control. I created the following
event handler that I've assigned to the KeyUp event of each of the TextBox
controls:

Have a look at the form's 'ActiveControl' property.

 

[Peter Steele]

That did the trick--thanks very much. I'm curious though--why did my loop
not work?

 

[Stoitcho Goutsev \(100\) [C# MVP]]

Hi Peter,
Probably because your textboxes are placed on a panel or other kind of
control. Controls collection keeps references to the immediate children
only. I suppose your textboxes are grand- or grand-grand-, etc children of
the form.

--
B\rgds
100

That did the trick--thanks very much. I'm curious though--why did my loop
not work?

 

[Peter Steele]

Actually, there are no panels or groups. The text boxes are direct children
of the form and their tab stops are numbered from 1 through 4...

Peter

Hi Peter,
Probably because your textboxes are placed on a panel or other kind of
control. Controls collection keeps references to the immediate children
only. I suppose your textboxes are grand- or grand-grand-, etc children of
the form.

 

[Stoitcho Goutsev \(100\) [C# MVP]]

Hi Peter,
In that case it has to work. I tested and everythink works fine. The only
problem with your loop is that when the last control in the tab order is
selected GetNextControl wouldn't loop back to the first one instead it would
simply returns null value. In that case your loop will throw
NullReferenceException because you don't check the returned value.
Anyways your loop works.

 

[Peter Steele]

That's really bizarre. My loop definitely does not work. I'll have to leave
it as a mystery for now I guess...

 

[Guest]

Your loop is not full. Each component have Controls property. In this collection store controls pointer's, which have Controls property too. You need use recursion algorithm for find focused component

 

[Peter Steele]

That's only an issue if I have nested controls in panels and group boxes. In
my case, all controls are direct children of the form so I knew a simple
loop would work. Except that for some mysterious reason it didn't. The
ActiveControl property is the way to do it though so I don't need the loop
in the end...

Your loop is not full. Each component have Controls property. In this

collection store controls pointer's, which have Controls property too. You
need use recursion algorithm for find focused component.