We help IT Professionals succeed at work.

Restricting input into fields

dealclickcouk
on
Medium Priority
346 Views
Last Modified: 2010-04-05

Hi I'm using Dev Express custom control DBInspector in Delphi5, to display info from a query.

The user is able to enter and update info via the control, but in certain rows I want to restrict input to numeric or spaces, the events for the rows are only OnChange, OnValidate, OnDrawCaption & OnDrawValue.

On a normal edit field it would simply be a case of using the event keypress, but with these limited events I'm not sure, any ideas?

Thanks
Comment
Watch Question

Unlock this solution and get a sample of our free trial.
(No credit card required)
UNLOCK SOLUTION

Author

Commented:

Hi, I've tried this code and got all sort of errors, plus I want allow numeric's this seems to stop them.

ie if I enter a char in the middle of the string is removes all to the left, if blank then causes an access violation error etc...
it was an example off the top of my head how to restrict characters using the OnChange event. You didn't say which chars you wanted to restrict, so i used the numerical characters as an example. Create a new application, drop a TEdit on the form and place the code in its onChange event and see what it does.

Of course, I have never used the DBInspector component, so I dont know how it acts to this code. I was only trying to give you an example of using a OnChange event to prevent keys versus the OnKeyPress event.

Shane
can you post you onchange event (code i displayed above that causes the area) so we can look?

Shane

Author

Commented:

When u say I didn't specify what chars, "restrict input to numeric or spaces" this from my original post gives a hint...

OK take this scenario...

field already has the following entry:

0115 939291

user insert into existing text:

0115 (mail first) 939291

the code you have supplied would (assuming it allowed only numerics & spaces)  not delete anything as your code only looks at the last char.

Also the line

 S:= InspectorPhoneWork.EditText;

only gives the var S what was last posted, so if blank to start with it would produce an error, even though text had been entered  because the change event happens before post.  I think this is strange, but this is what seems to be happening.


Well, you could just replace the ['1'........'9'] with ['A'...........'Z'....'a'........'z']

or

C:= S[length(S)];

  if (ord(C) >= 65) OR (ord(C) <= 90) OR
    (ord(C) >= 97) OR (ord(C) <= 122) then


Shane
Yeah, i see what you mean now with the last char............hmmmm, sorry, i dont have that DBInspector control to try things out with, maybe someone else has it here, im gonna listen in...........

Shane
Ferruccio AccalaiCEO and Co-founder
CERTIFIED EXPERT

Commented:
What about somethin like this?

procedure TForm1.Edit1Change(Sender: TObject);
VAR
I,J: Integer;
s : STring;
begin
J := Edit1.SelStart;
for i := 1 to length(Edit1.Text) do
  if Edit1.Text[i] in ['0'..'9',' '] then
    s := s+Edit1.Text[i];
Edit1.Text := s;
If J < Length( Edit1.Text) then
dec(j);
  Edit1.SelStart := J;
end;

F68 ;-)

Author

Commented:

What is the SelStart as this isn't valid within the inspector object? gives error undeclared identifier...
Ferruccio AccalaiCEO and Co-founder
CERTIFIED EXPERT

Commented:
mmm....that's for the caret position....
Just try skipping the selstart parts and tell us about the effect
Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a sample view!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.