This is happening because your changes from float to double are only on the C# side. Native code still stores everything in float, and in that particular case, as you are asking for a RoutedPropertyChangedEventArgs<double> and the data stored in memory are 2 floats, the raw conversion is accessing unknown memory.

You can hack your code in NoesisEvents.cs by forcing the use of float args in case T is double. It should work as RangeBase.ValueChanged is the only control using these float args:

public T OldValue

{

get

{

return typeof(T) == typeof(double) ?

(T)(object)(double)RoutedPropertyChangedEventArgsHelper.GetOldValue<float>(getCPtr(this)) :

RoutedPropertyChangedEventArgsHelper.GetOldValue<T>(getCPtr(this));

}

}

public T NewValue

{

get

{

return typeof(T) == typeof(double) ?

(T)(object)(double)RoutedPropertyChangedEventArgsHelper.GetNewValue<float>(getCPtr(this)) :

RoutedPropertyChangedEventArgsHelper.GetNewValue<T>(getCPtr(this));

}

}

Anyway, I will try to find a way to make this more robust in the native side.

Thank you for a quick reply, Sergio!

I'm reporting this as a bug as it was working fine before. So something has been changed.

Regarding the possible solution - I see it's possible to modify Extend.GetNativePropertyType so that it will return NativePropertyType.Float for double and decimal (and NativePropertyType.NullableFloat for the nullable counterparts).

Then you can rewrite GetOld/New value to use something like that:

int type = Extend.GetNativePropertyType(typeof(T));

IntPtr value = Noesis_RoutedPropertyChangedEventArgs_GetNewValue(cPtr, type); // or get old value

Error.Check();

var result = Extend.GetProxy(value, true);

return result is T || ReferenceEquals(result, null)

? (T)result

: Extend.ConvertValue<T>(result);

Seems to work fine here!

With C# 7.1 you can use it like this for better performance:

int type = Extend.GetNativePropertyType(typeof(T));

IntPtr value = Noesis_RoutedPropertyChangedEventArgs_GetNewValue(cPtr, type); // or get old value

Error.Check();

var result = Extend.GetProxy(value, true);

if (result is T castedResult)

{

return castedResult;

}
if (ReferenceEquals(result, null))

{

return default;

}
return Extend.ConvertValue<T>(result);

Hi Sergio,
as you've replied in another ticket:
"changing Extend.GetNativePropertyType to return Float for double/decimal types."
— I've done this and it indeed fixes the issue.
Will you use it as a primary solution to this issue or it might have some side effects?

No, it will have no side effects, it is safe to use it in your case.