C # later binding and calling COM components

 

Record the method for calling the local COM component using the C # non-binding method, so that you can search for yourself and those in need.

By adding reference to com components directly in the vs project, I will not talk about it here, mainly emphasizingPost-binding.

 

Step 1: Obtain the type exposed by the COM component based on the progid of the COM component:

Type comtype = type. gettypefromprogid ("your_com_progid ");

Step 2: Create an object of the type provided by the COM component (the final purpose is to call the method of this object ):

Object comobj = system. activator. createinstance (comtype );

Here, we need to call a method of the COM component, including the type and object, so it is easy to think of reflection:

Method method = comtype. getmethod ("method_name ");

If (method! = NULL)

Method. Invoke (comobj, paramters );

 

However, for the. net com component and the non-. Net COM component, the comtype is different:

• If the COM component is a. Net COM component, the above reflection call method is feasible;
• If the COM component is written in other languages such as VB and C ++, the above method is not feasible. The reason is that the metadata of the COM type is not obtained during the running, and the comtype obtained will be the unified packaging type system. _ comobject of all unknown COM components. The system. _ comobject class does not contain the method of the component you want to call. Therefore, comtype. getmethod ("method_name") cannot obtain the member method with the given name.

The correct method is to use the comtype. invokemember method after obtaining comtype and comobj:

Object returnobj = comtype. invokemember ("method_name"

, Bindingflags. invokemethod

, Null

, Comobj

, Paramters );