I'm working with a COM component which exposes a lot of Variant
properties, but sometimes these values are null. When I try to convert these values to string (or another Delphi type) the application raises an exception like this:
Could not convert variant of type (Null) into type (String)
But if I use .net to call the same properties and the values are null, no exceptions are raised and the null values are treated as empty strings.
My question there is a way to handle these null values from Delphi avoiding these exceptions?
Thanks in advance.
Try setting NullStrictConvert to False.
As it's a global variable I use it like follows to minimize side effects:
var
OldNullStrictConvert: Boolean;
begin
OldNullStrictConvert := NullStrictConvert;
NullStrictConvert := False;
try
// code containing conversions
finally
NullStrictConvert := OldNullStrictConvert;
end;
end;
(In reality I have made a guardian interface out of this.)
NB: Where it's feasible I prefer code like Warren's.
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