IsDigit function 1

[michaenh]

Hi everyone.

Is there any similar function in Delphi? ISDIGIT?
This function is to check if the value is a number(digit).
I have used this in Java and C++.

In delphi I want to check the user input from a combobox. If the user write some text then a message box will prompt that the user only can write numbers.

Maybe there are some easy properties?

Million thanks
Michael

 

[KempCGDR]

I use something like:

For i := 1 to Length(edtQty.Text) do //Check it's a number
If (edtQty.Text[ i ] < '0') or (edtQty.Text[ i ] > '9') then Accept := False;

Ignoring the spaces within the [ and ] obviously.

 

[bbegley]

You could also test StrToInt (or StrToFloat) inside a try block

Try
StrToInt(Edit1.text);
except
Edit1.Field.Clear;
Showmessage('Use a number');
end;

if the editbox is not data aware you would use something like

Try
i := StrToInt(Edit1.text);
except
Edit1.text := '';
Showmessage('Use a number');
end;
Brian
&quot;There are 2 kinds of people in the world, those that divide people into two groups and those that don't. I belong to the second group.&quot; - tag line I stole

 

[Zathras]

Instead of slapping the user's hand when he makes a mistake, I prefer to prevent the mistake from being made in the first place when possible.

For example, here's a way to restrict the user when only numbers are valid in a text field:

{User typing an account number.  Restrict entry to numbers, Esc and Ctrl-Z}

procedure TQSpecs.dfAccountKeyPress(Sender: TObject; var Key: Char);
begin
  if Key in [#26,#27] then dfAccount.Text := IntToStr(FAccountKey);
  if not (Key in ['0'..'9',#8,#26,#27]) then Key := Char(0);
end;

 

[LucieLastic]

...I just have the following in mine:

procedure TFormCoList.edCoIDKeyPress(Sender: TObject; var Key: Char);
begin
if not (key in ['0'..'9', #8,#9]) then key := #0;
end;

 

[Zathras]

I allow the users to use Esc (#27) and Ctrl-Z (#26) as an &quot;undo&quot; by restoring the original value that was captured on entry in a TEdit. (Part of my definition of &quot;user friendly.&quot -- Use of the Escape key is old school. Ctrl-Z seems to be the new Windows standard. But, probably not needed for a list/combo box.

Tab (#9) is used by Windows and is not sent to the procedure, so no need to look for it.

 

[michaenh]

Wow! Thank you guys.. )

Everyone should get a star here, but it would be to much stars in this thread. So I will give two stars to Zathras. I like the way you are thinking.

Thanks guys.

Michael

 

[sggaunt]

On a different tack, have a look at the MaskEdit component, you can set this up to allow only numeric input.
Steve