editbox / combobox text check for charicaters?

[cazzajay]

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 

[theo]

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"?

[cazzajay]

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...

[Blaazen]

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.

[Marc]

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...


[Blaazen]

Marc:

to make sure the edit text is not retrieved on every call, better store it locally first

I'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.

[Blaazen]

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.

[cazzajay]

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.

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

[Blaazen]

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

[cazzajay]

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

[Blaazen]

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.

[Garry Hopkins]

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

[samps]

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