I am writing a program which accesses a Microsoft Access database and inserts baseball card info in.
The program works flawlessly 95% of the time, however I get this random error which crashes the program.
It says: "Could not convert variant of type (Null) into type (string).
Any Ideas? If it would help I can upload or email a copy of my files.
Please let me know if anyone has seen this...I'm new to delphi but I've put alot of time into this program.
*----------------------------------------*
There are two ways to write error-free programs; only the third one works.
Comments
OK it seems to have something to do with the following:
Before a new record is sorted, the program checks to see if the record exists, if so, it just updates the quantity field and total value field.
I check by using a series of nested if then statements.
The field that seems to be causing the problem is named 'CardDesc'. It contains special information of the card (ie if it is a gold card, rookie card, etc.) the problem seems to arise when there is nothing in the field at all. The program tries to set CardDescStr:=ADOTable2.FieldByName('cardDesc').value;
and I'm guessing that's where the error comes from. Any ideas?
*----------------------------------------*
There are two ways to write error-free programs; only the third one works.
:
: OK it seems to have something to do with the following:
:
: Before a new record is sorted, the program checks to see if the record exists, if so, it just updates the quantity field and total value field.
:
: I check by using a series of nested if then statements.
:
: The field that seems to be causing the problem is named 'CardDesc'. It contains special information of the card (ie if it is a gold card, rookie card, etc.) the problem seems to arise when there is nothing in the field at all. The program tries to set CardDescStr:=ADOTable2.FieldByName('cardDesc').value;
: and I'm guessing that's where the error comes from. Any ideas?
: *----------------------------------------*
:
: There are two ways to write error-free programs; only the third one works.
:
:
:
:
Why do you use .Value for FieldByName and not .AsString if you know that it is a string?
I always use specific .AsString, .AsInteger, AsBoolean, etc and find that it works very well for me.
//Ulvert