Can we override tabstop property of control?

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I have a usercontrol which is derived from control, can i override the TabStop property to have some modification.?
If so please let me know, how to override the tabstop property in my usercontrol.

What I have tried:

i have tried to override the tabstop in my usercontrol, but the tabstop property is not listed in override properties

Posted 25-May-16 20:35pm

AmalRaj@Sync

Updated 25-May-16 21:00pm

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BillWoodruff 26-May-16 6:02am

I think you need to state clearly what your goal is here: how exactly do you want your UserControl to "behave" when:

1. an instance of it is on a Form

2. an instnace of it is in another container, like a Panel, on a Form

Exactly what do you want to see happen when the Tab Key is pressed in these scenarios ?

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OriginalGriff · Answer 1 · 2016-05-25T21:00:00

Solution 1

Tabstop is just a bool, which tells the system that the user input focus can go to the control when he presses the TAB key: if it's true, the control is included in the "tabable" controls collection at the position indicated by the TabIndex property. Overriding it (which you can't do as it's not marked virtual, abstract, or override) wouldn't allow you to add and real functionality to the tab process. You can hide teh original implementation:

C#

public new  bool TabStop { get; set; }

Which would probably prevent the TAB key from ever being used to enter it, but that's about all.
If you want to modify TAB behaviour (and I really don't recommend it) you probably need to override ~~WndProc~~ ProcessCmdKey in the parent container and filter out TAB yourself.

Ignore WndProc, you need ProcessCommandKey (my caffeine hadn;t kicked in fully last time):

C#

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
    {
    Keys keyPressed = (Keys)(int)msg.WParam;
    if (keyData == Keys.Tab)
        {
        Console.WriteLine("Tab!");
        return true;
        }
    return base.ProcessCmdKey(ref msg, keyData);
    }

But seriously: Faff with TAB functionality at your own risk! Users are used to it doing particular things, and you really don't want to subvert that or they will hate your app with a passion you will not believe...

Posted 25-May-16 21:00pm

OriginalGriff

Updated 25-May-16 21:30pm

v2

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AmalRaj@Sync 26-May-16 3:03am

Thanks. How to identify the tab key pressed through WndProc?

OriginalGriff 26-May-16 3:30am

Answer updated.

AmalRaj@Sync 26-May-16 3:41am

when i press tab key from other controls, the override processcmdkey doesnt hit.

I want to stop the focus of my usercontrol when moving from other controls using tabkey

OriginalGriff 26-May-16 3:58am

I did say "...in the parent container..."
You can't trap in in your control because it's already been processed. Almost certainly, you need to override the method for the form that your UserControl is part of.

AmalRaj@Sync 26-May-16 4:48am

the usercontrol which i placed in a panel only gets focus even when the TabStop for usercontrol is set to false.

But the same usercontrol which is not placed in a panel(simply placed in form), didnt get focus when i set TabStop to false.

is there any reason why the userCOntrol gets focused only when it is placed inside a panel?

OriginalGriff 26-May-16 4:53am

That doesn't make a whole lot of sense to me in isolation.
Would you like to explain in more detail exactly what you did and what problem it gave?

AmalRaj@Sync 26-May-16 5:02am

in one sample, i just placed my usercontrol and some other controls like button and combo box in form and when i set myUserCOntrol.TabStop = false and when i move through other controls by Tab key, my usercontrol didnt get focused.

But in another sample, i have placed the same user control inside a panel which same set of other controls, but here the usercontrol gets focus even when TabStop is set to false

OriginalGriff 26-May-16 5:40am

I just tried it here:
1) Create a usercontrol called MyUserControl, add 2 text boxes and a button. Build project.
2) Add a MyUserControl directly to a form. Set TabStop to false.
3) Add a Panel directly to the form. Add a MyUserControl to the Panel. Set TabStop to false.
4) Run.
TAB did not go to any of the textboxes or buttons in either of the MyUserControl instances.
Changing TabStop to true on either (or both) MyUserControl instances let TAB work exactly as I would expect.

So what did I do that is different from what you did?

BillWoodruff 26-May-16 6:00am

+5

Can we override tabstop property of control?

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Can we override tabstop property of control?

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