Problem with Activator.CreateInstance in C#

[Doug Riley]

I am using CreateInstance to create an instance of a class and invoke
a function of that class. I really need it to execute in a single
line of code (long story, but I want to execute this code in the
command window on demand, without declaring any variables).

This code WORKS (but requires 2 lines of code and a variable
declaration):
Type typ = Type.GetTypeFromProgID("MyDLLx.clsMyClass");
Activator.CreateInstance(typ).mNoShow("Test");

This Code DOES NOT WORK:
Activator.CreateInstance((System.Type)Type.GetTypeFromProgID("MyDLLx.clsMyClass")))).mNoShow("Test");

The error, when executed from the command window is:
arguments do not match parameters for function ...

The error (compile), when coded in the application is:
\'object' does not contain a definition for 'mNoShow'

Any help is most appreciated.

 

[Daniel O'Connell [C# MVP]]

Type typ = Type.GetTypeFromProgID("MyDLLx.clsMyClass");
Activator.CreateInstance(typ).mNoShow("Test");

This Code DOES NOT WORK:
Activator.CreateInstance((System.Type)Type.GetTypeFromProgID("MyDLLx.clsMyClass")))).mNoShow("Test");

The error, when executed from the command window is:
arguments do not match parameters for function ...

The error (compile), when coded in the application is:
\'object' does not contain a definition for 'mNoShow'

Any help is most appreciated.

Are you sure these are verbatim lines? Neither one will work.(Although it
probably will in VB)

 

[Nicholas Paldino [.NET/C# MVP]]

Doug,

Actually, neither line of code should work. The reason for this is that
the CreateInstance method returns an object. The only way I can see this
working is if it is in VB.

I would recheck the two lines you say that work, because they shouldn't.

Is it possible that the two lines are in a block that is swallowing the
exception?

 

[James Curran]

If you remove the needless cast, and the two extra close parentheses, you
are left with:

Activator.CreateInstance(Type.GetTypeFromProgID("MyDLLx.clsMyClass")).mNoSho
w("Test");

Which compiles (except for the error Daniel & Nicholas pointed out)

--
Truth,
James Curran
[erstwhile VC++ MVP]
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