How to prevent a TextBox to accept Unicode control characters?

Question

I have scenarios that don't want the end user to input Unicode control characters to the Windows.Forms.TextBox, as you may know, if you right click a TextBox, a context menu will shown and the last menu item on this context menu is "Insert Unicode control character->", which can insert some Unicode control characters into the TextBox.

Is there anybody knows how to disable or hide these menus -> "Insert Unicode control character", "Show Unicode control characters".

You can disable the context menu all together by using `textBox1.ContextMenu = new ContextMenu();` if that's an option. — Bala R, Jul 05 '11 at 15:27

score 1 · Answer 1 · edited May 23 '17 at 12:04

Even if you disable this context menu entry, the user can still enter all kinds of strange characters using copy & paste or using Alt-Numpad. If you want to restrict your input strictly to, say, A-Z, you can use a MaskedTextBox control.

If you need more fine-grained control, you can handle the TextBox.KeyPress Event. An example of this technique can be found in the following SO question:

How do I make a textbox that only accepts numbers?

score 1 · Answer 2 · edited Dec 06 '13 at 14:40

1

Override your text box ContextMenu.

Design you own ContextMenu and implement only the functionality you want on it. and then assign that contextMenu to your textBox: myTextBox.ContextMenu = myContextMenu;

edited Dec 06 '13 at 14:40

BenMorel

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answered Jul 05 '11 at 15:28

Jalal Said

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score 1 · Answer 3 · answered Jul 05 '11 at 15:40

1

To add to Jalal's answer,

var contextMenu = new ContextMenu();
contextMenu.MenuItems.Add(new MenuItem("Copy", (s, ea) => textBox1.Copy()));
contextMenu.MenuItems.Add(new MenuItem("Paste", (s, ea) => textBox1.Paste()));
contextMenu.MenuItems.Add(new MenuItem("Undo", (s, ea) => textBox1.Undo()));
contextMenu.MenuItems.Add(new MenuItem("Select All", (s, ea) => textBox1.SelectAll()));
....

textBox1.ContextMenu = contextMenu;

answered Jul 05 '11 at 15:40

Bala R

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Thanks for you solution. I have couple of datagridview and textboxes, replacing everything concerns me a bit. But I have the same app in vb where these menus are not displayed by default. – Joboy Jul 05 '11 at 17:53

How to prevent a TextBox to accept Unicode control characters?

3 Answers3