[SOLVED] Compare date in StringGrid

[MarcCoo]

Hello together!

I've got a StringGrid with a few holidays, the date of the beginning in col2 and the date of the end in col3.
In the Listbox is a date (or more) and now I wanna check if the date is in the holidays.
Since three days I try to find a way, hopefully someone can help me a bit.

Code: Pascal  [Select][+][-]

1. // function IsHoliday ?
2. function TForm1.IsHoliday(holiday: string):string;
3. var
4.   s: string;
5.   i: Integer;
6.   id: integer;
7.   D1: string;
8.   D2: string;
9. begin
10.   try
11.     for id :=0 to StringGrid2.RowCount -1 do;
12.      begin
13.           for i:=0 to ListBox1.Items.Count -1 do;
14.             begin
15.               D1:= StringGrid2.Cells[2,id];
16.               D2:= StringGrid2.Cells[3,id];
17.               S:= ListBox1.Items.Strings[i];
18.  
19.               if (StrToDate(S) >= StrToDate(D1)) and
20.                  (StrToDate(S) <= StrToDate(D2)) then
21.                begin
22.                result:= 'yes holiday';
23.                end
24.             else
25.             begin
26.             end
27.              end;
28.          else
29.          begin
30.            result:= 'no :-(';
31.       end;
32.   finally
33.   end;
34.   end;            
35.  

[wp]

You don't say what's the problem.

Maybe crashing due to invalid date? This could happen if your StringGrid has a header row containing non-date strings. Since your id loop begins with 0 it tries to convert the header text to a date. Start it at 1 or, more general, at StringGrid2.FixedRows to skip the header row.

[MarcCoo]

Aww...yeah true!

My Problem is, that the Code only works with the last holiday in the rows.
Sample:
Christmas 15.12.2017 - 05.01.2018
Spring 06.02.2018 - 18.02.2018
Easter 06.03.2018 - 17.03.2018

Only for Easter I get a feedback, for the other dates the code doesn't work.

[wp]

Please post a sample project (only .pas, .lfm, .lpr and .lpi files packed as a common .zip which you can upload under "Attachments and other option" below the edit field).

[MarcCoo]

Hey, thank you.
Here is my little programm to calculate my busses...
the function is:

// Prozedur IstHoliday ?
function TForm1.IstRabatt

[wp]

Sorry, I'm glad to help but I am not going to take my time to debug a full application which requires me to install other thirdparty packages, is in a language which I don't understand (ok - this does not count here, I am German, but others are not) and which I don't know how to use. If you really want me to take my time to help you, you must take your time to write a little demo application which does nothing else but show the error. Usually, people find the bug by themselves along the way...

[MarcCoo]

For sure mate!
That was a bit thoughtless from me. A clean, easy sample will come...

[MarcCoo]

So now a bit cleaner and with no third-party-stuff   

Only for the dates in the last row I get the right answer.
Maybe I have to set a break as soon as something has been found? 

[wp]

OK, I should have seen it in your posted code above, but without the debugger I am blind...

Two issues

• If you add a semicolon after the "do" of the "for" instruction then the loop ends exactly there, and the block below is not considered to belong to the loop.
• You must exit the loop once a holiday has been found because if a non-holiday region follows the Edit.Caption will be reset to "no".

Another remark: There's no need for a try-finally block here. Try-finally is for resource protection since  the finally block is always executed and can be used to free resources.

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var
3.   s: string;
4.   i: Integer;
5.   id: integer;
6.   D1: string;
7.   D2: string;
8. begin
9.     // Begin loop at id = 1 to skip the non-date header
10.     for id :=1 to StringGrid1.RowCount -1 do    //  <--- NO SEMICOLON HERE
11.      begin
12.           for i:=0 to ListBox1.Items.Count -1 do   //  <-- NO SEMICOLON HERE
13.             begin
14.               D1:= StringGrid1.Cells[2,id];
15.               D2:= StringGrid1.Cells[3,id];
16.               S:= ListBox1.Items.Strings[i];
17.  
18.             if (StrToDate(S) >= StrToDate(D1)) and
19.                (StrToDate(S) <= StrToDate(D2)) then
20.                begin
21.                   Edit1.Caption:= 'yes holiday!';
22.                   exit;    // <--- Exit the procedure once a holiday is found.
23.                end
24.                 else
25.                 begin
26.                    Edit1.Caption:= 'no';
27.                 end
28.               end;
29.      end;
30.   end;

[MarcCoo]

Aww! 
I never stop learning.

I tried with break and exit before, but never seen that the issue is the semicolon...
will keep that in my mind.

Thank you soo much wp!