Invoke method using Reflection on COM Object

问题:

I have an instance of a COM object... which is created like this:

Type type = TypeDelegator.GetTypeFromProgID("Broker.Application");
Object application = Activator.CreateInstance(type);

When I try to invoke a method:

type.GetMethod("RefreshAll").Invoke(application, null);

-> type.GetMethod("RefreshAll") returns null. When I try to get all the methods with type.GetMethods(), there is only these methods:

1. GetLifetimeService
2. InitializeLifetimeService
3. CreateObjRef
4. ToString
5. Equals
6. GetHashCode
7. GetType

Where is the RefreshAll Method? And how can I invoke it?

回答1:

You can't use GetMethod on COM objects, you have to use a different way:

this.application.GetType().InvokeMember("RefreshAll", BindingFlags.InvokeMethod, null, this.application, null);

I am using this way in a old project that uses COM so it should work ok for you.

回答2:

I realise this is a late answer but c# 4 changes things a bit with the introduction of the dynamic keyword which was designed with COM-interop in mind.

MSDN:

The COM interop scenario that the C# team specifically targeted in the C# 4 release was programming against Microsoft Office applications, such as Word and Excel. The intent was to make this task as easy and natural in C# as it always was in Visual Basic. [1]

Your code now becomes:

Type type = TypeDelegator.GetTypeFromProgID("Broker.Application");
dynamic application = Activator.CreateInstance(type);
application.RefreshAll(); // <---- new in c# 4

Now you won't see RefreshAll() in Visual Studio statement completion so don't be alarmed. It will compile.

[1] Understanding the Dynamic Keyword in C# 4