I have a little problem - in my Windows Forms program I have a lot of text boxes. They only can get numeric values between 1 - 1024. "Protecting" the text box form non numeric inputs is no problem. But how can I assure that the value doesn't get higher than 1024? Is there any function or any event I could try to catch and then Handle it on my own? I thought about catching the "TextChanged" Event and then check for the value. But how can I know then which Button was the last one pressed?
Besides I wouldn't like to exchange my Textboxes with any other Controls since they're all implemented right now and it would be a lot of work to exchange them all.
Best Regards
Quendras
You should use the NumericUpDown control and set the Maximum property.
You could try using OnLostFocus on each text box. Then verify the input was numeric, and it's value is greater/equal to 0, and less/equal to 1024.
You could check when that textbox loses focus, and then check its value:
public sub Textbox1_lostFocus() handles textbox1.onLostFocus
If cint(textbox1.text) > 1024 then
'whatever you need to do here
End if
end sub
Related
I have a problem with changing all textboxes in a form with Null to a Value 0.0 after Lost Focus. Specifically, if the textbox is blank after pressing tab it would revert back to 0 since it affects calculations in the other part of the form. Writing the code for every textbox event procedure (57 or so boxes) seems tedious and the names for all the boxes are different.
I was wondering if there was an efficient way to go about changing the textbox value after losing focus easily rather than changing the event procedure for every textbox in the form.
Thanks
Figured I would give an example along with my comments. You could use something along these lines:
Public Function DefaultToZero(frm As Form)
Dim ctrl As Access.Control
For Each ctrl In frm
If ctrl.Tag = "Default" Then
If Nz(ctrl.Value, "") = "" Then
ctrl.Value= "0.0"
End If
End If
Next ctrl
End Function
Then you just select all controls while in design mode and set the tag to 'Default'. Not the best answer but I don't really see any other options besides using each "Lost Focus" event.
I have a numericUpDown picker that's set to a range of acceptable years, defaulting to the current year.
The user can edit the number in the box with the keyboard: say if the number in there is 2011 to begin with, they can press backspace and the number in the box on screen will be 201. However, as far as I know, the value property of the control will never read a number below the minimum I set (1900 in this case).
I need a way to get the number currently in the box on the screen regardless of whether it is in my acceptable range or not. Anyone know how to do this?
Thanks!
You can use the NumericUpDown.Text property to get the current text, then parse to int. It may not look like the property exists, but it's there.
The Text has no affect on the appearance of the NumericUpDown control; therefore, it is hidden in the designer and from IntelliSense.
I'm making my own commentbox control that inherits from a winforms textbox. One of the things it does is prevent users from entering any characters if the limit has been hit. So on the keypress event I just grab the incoming key (excepting delete and backspace) and add it on to what's in the textbox already, then check and see what the length is. If it is over, then I just set the e.Handled = true and the keypress is halted. This scheme fails me though on an incoming ctrl-v paste event. It registers as a single keychar coming in. So the paste won't come through if I'm right at the limit, but it will go over if there is one character of room left and the paste has two or more characters for instance.
I just need a way to detect that this paste is coming in, and when its coming in I need to know what the length of the string is so I can either stop it from happening or paste as much of it as possible in there.
Thanks!
This is such an idle question. You can just set the MaxLength property of the textbox and it prevents all of this. Duh.
I have a WPF textbox, and perform the following actions
Enter text as "12345"
Move cursor between 3 and 4 (using arrow or
mouseclick)
Enter 0 (so Text is now "123045")
Which event/eventargs can tell me that 0 was typed at location 4.
I need to know this at Preview level so that I can reject the character 0 based on the prefixed and suffixed digits.
In PreviewTextInput event you can use the TextBox's CaretIndex property to know the location where input is being typed.
You can use the PreviewTextInput event. (see here for a complete example)
When editing text the user is able to use the keybord shift button and direction keys to modify the selection - one position stays anchored while the other moves. By pressing left it is possible to get the movable part on the left of the anchored part.
I'm trying to dinamicaly modify the users selection in WPF's TextBox (for the purpose of the discussion, lets say I want to select the characters in pairs, eg. when pressing shift+left, 2 characters would get selected, not just one). However, when using SelectionStart/SelectionIndex/CaretIndex/Select the "movebale end" of the selection is always ends up on the far right end of the selection, rendering the shift+left combination useless.
Any way to preserve the "selection direction"?
This is not quite the answer you are looking for but it'll work. Invoke the command and do it the way WPF does it.
EditingCommands.SelectLeftByCharacter.Execute(null, textBox1);
None of those work. SelectionLength doesn't allowed to be negative, and CaretIndex is always identical to SelectionStart. This is a design bug in TB, as you cannot achieve a valid state of it even in the protected scope.
The command actually works, but you still cannot determine the selection's direction of the currently analyzed textbox. There's only one solution, which is an ugly workaround: You can write your own observer code by overriding the mouse and keyboard event handlers.
The only possibility I can think of is to set the SelectionStart and then make the SelectionLength negative.
Have you tried setting the CaretIndex property before or after setting SelectionStart/SelectionLength?