Inconsistency in passing objects from VBA to .NET via COM
- by Akash
I have the following interface defined to expose a .NET class to COM:
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
[Guid("6A983BCC-5C83-4b30-8400-690763939659")]
[ComVisible(true)]
public interface IComClass
{
object Value { get; set; }
object GetValue();
void SetValue(object value);
}
The implementation of this interface is trivial:
[ClassInterface(ClassInterfaceType.None)]
[Guid("66D0490F-718A-4722-8425-606A6C999B82")]
[ComVisible(true)]
public class ComClass : IComClass
{
private object _value = 123.456;
public object Value
{
get
{
return this._value;
}
set
{
this._value = value;
}
}
public object GetValue()
{
return this._value;
}
public void SetValue(object value)
{
this._value = value;
}
}
I have then registered this using RegAsm, and tried to call it from Excel via the following code:
Public Sub ComInterop()
Dim cc As ComClass
Set cc = New ComClass
cc.SetValue (555.555)
valueByGetter = cc.GetValue
valueByProperty = cc.Value
cc.Value = 555.555
End Sub
When I step throught this code, valueByGetter = 555.5555 and valueByProperty = 555.555 as expected. However, I get an "Object required" runtime error on the final line.
Why does setting the value via the setter method work but setting via the property fail? What do I have to change to get the property to work as expected?
