By Adam Nagy
Let's say we have the following code:
// First select a RectangularPatternFeature then run the code
CComQIPtr<RectangularPatternFeature> pPattern =
pInvApp->ActiveDocument->SelectSet->Item[1];
for (int i = 1; i <= pPattern->PatternElements->Count; i++)
{
CComPtr<FeaturePatternElement> pElem =
pPattern->PatternElements->Item[i];
// In this case there is no crash
pElem->put_Suppressed(false); // or true
// No matter if I use false or true
// both cases will cause an error
pElem->Suppressed = false; // or true
}
The difference between put_Suppressed(false) and Suppressed = false is that the former is the raw interface which simply provides an HRESULT value to let you know if there was an error, while the latter is a wrapper around it that is throwing a _com_error exception in case of an error.
You can also check the rxinventor.tli file of your project to see the exact implementation of the raw and wrapper functions:
#pragma implementation_key(29648)
inline void Inventor::RectangularPatternFeature::PutSuppressed ( VARIANT_BOOL _arg1 ) {
_com_dispatch_method(this, 0x500030a, DISPATCH_PROPERTYPUT, VT_EMPTY, NULL,
L"\x000b", _arg1);
}
#pragma implementation_key(29649)
inline HRESULT Inventor::RectangularPatternFeature::put_Suppressed ( VARIANT_BOOL _arg1 ) {
return _com_dispatch_raw_method(this, 0x500030a, DISPATCH_PROPERTYPUT, VT_EMPTY, NULL,
L"\x000b", _arg1);
}
What is the error in our code? The problem is that the first element of a rectangular pattern cannot be suppressed – you can easily verify this in the user interface:
While put_Suppressed(false) simply returns an error code, Suppressed = false will throw an error that you would need to catch. You can solve it like this:
// First select a RectangularPatternFeature then run the code
CComQIPtr<RectangularPatternFeature> pPattern =
pInvApp->ActiveDocument->SelectSet->Item[1];
for (int i = 1; i <= pPattern->PatternElements->Count; i++)
{
CComPtr<FeaturePatternElement> pElem =
pPattern->PatternElements->Item[i];
// In this case no crash
pElem->put_Suppressed(false); // or true
// Now we catch the error so nothing will crash
// Note: the real solution would be to start the iteration
// from 2 instead of 1 if we just want to change the
// Suppressed state of the items. I left it on 1 just to
// show that the error handling works
try
{
pElem->Suppressed = false; // or true
}
catch (_com_error e)
{
// do something if you want
}
}
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