editbox  / combobox text check for charicaters?
lazarus / 10-Designer

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cazzajay · 2009-10-09 07:20

i have some edits and combo boxes that end up creating filenames.  is
there any way to run a little procedure to check to ensure they don't
contain the windows-forbidden characters such as ! etc?

im looking for as simple a solution as possible, any help?

thanks

cj

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theo · 2009-10-09 09:10

What is exactly your question?
You don't know how to scan a string for certain characters?
Or you don't know which event to use for checking the content of some
controls?
What do you mean with "simple a solution as possible"?

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cazzajay · 2009-11-18 18:15

ok ive managed to work around this but the problem has cropped up
again.

i have an edit box, and i want to scan every single character in that
box to check it ain't from a known "bad list".  pseudocode something
like:


y := 0
i := edit1.length

for j := 0 to i do
begin
if edit1.character[j] = '!' then y := y + 1;
end;

for x := 0 to i do
begin
if edit1.character[j] = '$' then y := y + 1;
end;

if y > 1 then
begin
showmessage('Dont be an idiot - you cant use ! or $ in that field');
exit;
end;


except i cant find the right bits for edit1.character[j] and
edit1.length

and the same for a memobox...

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Blaazen · 2009-11-18 18:59

Hi,
I think so

Code: [Select]i:=length(Edit1.Text);
and

Code: [Select]for j:=1 to i do
begin
  if Edit1.Text[j] = '!' then ....
Is important to start the loop from 1.

You can try this wild characters remove automatically.

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Marc · 2009-11-18 19:21

to make sure the edit text is not retrieved on every call, better
store it locally first. Code: [Select]var
  S: String;
  n: Integer;
begin
  S := Edit1.Text;
  for n := 1 to Length(S) do...

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Blaazen · 2009-11-18 20:52

Marc:
Quoteto make sure the edit text is not retrieved on every call, better
store it locally firstI'm interested in this. Is this faster - I mean
making local variable rather than accessing object preperty again and
again ?

I usually do it, but sometimes not, I never tested difference.

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Blaazen · 2009-11-18 21:27

I made little test (measured using function Now) and it seems
searching in local string variable is more than 200 times faster than
accessing object property.

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cazzajay · 2009-11-19 12:44

Quote from: Blaazen on November 18, 2009, 10:27:43 pmI made little
test (measured using function Now) and it seems searching in local
string variable is more than 200 times faster than accessing object
property.



Really? I had no idea!!!  What OS is that on?

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Blaazen · 2009-11-19 14:29

On Kubuntu 9.10, Qt 4.5, 64 bit, i can give here code but now I am
away from my PC.

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cazzajay · 2009-11-19 14:59

dont worry about it - i did it the local variable way, on win32, and
the difference is hardly noticeable but even so - nice to have my app
running at its optimum

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Blaazen · 2009-11-20 00:23

Here is a little test, code is simple, I hope it will work on your PCs
(it is without project1.lrs file)

Edit: Be patient, test run ~ 15 seconds.
On my CPU Intel Penryn 7350 2GHz usually multiplication is 3.2x faster
and searching in local variable is 150 - 250 x faster, depend on
length of string and also if test run from Lazarus (under debugger) or
normally from binary.

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Garry Hopkins · 2010-01-08 09:56

Blaazen has worked this out,any issues after this? I think this should
work.

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samps · 2010-04-22 03:44

Windows don't mind the '!' character. In fact, I use it often to
ensure MY stuff is listed first..


I would use SETs to discern what is filename legal and what's not:


goodies = SET of CHAR;

goodies = [a..z,A..Z,0..9,!,[,],etc.....];


while i < length(filename) do
    if filename not in goodies then filename i := whatever-fallback-
character-routine-returns


That's the idea anyway, mind the syntax (why isn't there a syntax
highlighter/grammar checker for web content? Like: TinyMCE on proggin'
steroids?)


cheers
Samps