class EVariantTypeCastError with message 'Could not convert variant of type (String) into type (Double)
delphi, fastreport
Solution
This is just the debugger. It's probably just getting an expected error (one handled by a `try..except` in the FR code) and properly dealing with it, but the debugger has no way of knowing that and tells you the exception happened. (It's a common issue when working with Indy, which raises exceptions as part of normal program flow.)
There are three ways to deal with this situation when debugging:
Just hit `Continue` on the exception dialog when it appears. (You can tell it's a debugger exception because you get the `Break` or `Continue` option, and because it only happens when debugging.)
You can disable a specific exception class (or all exceptions) when debugging, using the `Tools->Options->Debugger Options`. In this case, you can add `EVariantTypeCastError` to the list of exceptions to ignore.
(My preferred method) Use the `Advanced Breakpoint Properties` dialog to skip the debugger's exception handling around the specific line of code you know will raise the exception you want to ignore.
- Set a breakpoint on the line immediately before the problem code line.
- Right-click the breakpoint on the line before, and choose `Breakpoint Properties` from the context menu.
- Click the `Advanced` button on the `Breakpoint Properties` dialog, and in the `Actions` groupbox, uncheck `Break` and check `Ignore subsequent exceptions`.
- Repeat the previous steps on the line after the problem code, except check `Break` and uncheck `Ignore subsequent exceptions` on this second breakpoint.
- Run your code as usual. The debugger will skip it's exception handling on the code between the two breakpoints.
The advantage of option #3 is that it ignores all exception handling, but only on the code block between the two breakpoints, so you still get exceptions in all other areas of your code that may be valid exceptions in the debugger.
Problem
Using Delphi and FastReport I get this error message while debugging inside Delphi immediately after this line: ``` <FastReport_Component>.ShowReport(true); ``` Then this error appear: Project myapp.exe raised exception class EVariantTypeCastError with message 'Could not convert variant of type (String) into type (Double)'. It appears twice before displaying the report. but if I run myapp without debugging no error message appear. How I can find which memo cause this error ? the report has so many memos. some has also expressions inside using `IIF` and the error message does not display any more info.