Sven Barth schrieb:
If you want to ensure that MyInstance is Nil you need to do it like this:
=== code begin ===
try
MyInstance := TMyClass.Create('AnNonExistentFile');
except
MyInstance := Nil;
end;
=== code end ===
When an exception occurs in Create, the assignment will never take
place. That's why MyInstance should be set to Nil *before* calling the
constructor. This also applies to memory leak protection of multiple
temporary objects:
inst1 := nil;
inst2 := nil;
...
try
inst1 := T1.Create;
inst2 := T2.Create;
...
finally
inst1.Free;
inst2.Free;
...
end;
The Free does no harm, even if the instances never were created, when
the variables are nil'ed before the try block.
DoDi
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