asked on
Can I improve my .NET COM object to catch usage errors at compile time in VB6
For some time now I've been writing C# COM visible DLLs for use in an old VB6 application.
I've recently become aware that my COM visible class isn't browsable in the Object Browser nor does the IDE catch compile-time errors. Here's a sample interface and class:
I've recently become aware that my COM visible class isn't browsable in the Object Browser nor does the IDE catch compile-time errors. Here's a sample interface and class:
namespace Sample
{
[Guid("FDB56085-E1C2-41E3-8B6A-86F734B9338B")]
public interface ITest
{
#region Methods
void Foo();
void Bar();
#endregion
}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[Guid("6717C7FC-9E3F-47A1-955C-09734F96B18F")]
public class Test: ITest
{
#region Public Methods
public void Foo()
{
}
public void Bar()
{
}
#endregion
}
}
Dim tAs Sample.Test
t.Foo
t.Bar
t.CompileError
.NET Programming* ActiveX* COM ObjectsC#Visual Basic Classic
Last Comment
Russ Suter
do you have a reference in VB6 to your COM object? Are you using early or late binding?
ASKER
Specifically, I want to enforce early binding. I actually found a couple of answers but I'm unclear on a minor point.
Solution 1: Don't bother with an interface and add set the ClassInterface attribute of the class like this:
Solution 2: Set the InterfaceType attribute of the interface like this:
Solution 3: Set the InterfaceType attribute of the interface like this:
In any event, right now I'm using solution 3 and letting the VB6 IDE compiler tell me where things are wrong. It's functional and it's getting me further along. I just wish I knew what the actual difference is between solution #2 and #3.
Solution 1: Don't bother with an interface and add set the ClassInterface attribute of the class like this:
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.AutoDual)]
[Guid("6717C7FC-9E3F-47A1-955C-09734F96B18F")]
public class Test: ITest
Solution 2: Set the InterfaceType attribute of the interface like this:
[Guid("FDB56085-E1C2-41E3-8B6A-86F734B9338B")]
[InterfaceType(ComInterfaceType.InterfaceIsIInspectable)]
public interface ITest
Solution 3: Set the InterfaceType attribute of the interface like this:
[Guid("FDB56085-E1C2-41E3-8B6A-86F734B9338B")]
[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIIUnknown)]
public interface ITest
In any event, right now I'm using solution 3 and letting the VB6 IDE compiler tell me where things are wrong. It's functional and it's getting me further along. I just wish I knew what the actual difference is between solution #2 and #3.
ASKER CERTIFIED SOLUTION
THIS SOLUTION ONLY AVAILABLE TO MEMBERS.
View this solution by signing up for a free trial.
Members can start a 7-Day free trial and enjoy unlimited access to the platform.
ASKER
I had already reached that conclusion (see my post above). Thanks though.