问题
I've made a simple C# DLL (that's part of a much larger project) using VS2005. I need to use the DLL in Excel via VBA code so I am using COM Interop on the assembly. I am trying to make the build process automatically generate the necessary TLB file so that I don't need to go to the command line and use regasm after every build.
My problem is that although the DLL compiles and builds fine, it does not generate a TLB file. Instead, the error in the title prints out in the output box.
I've gotten other DLLs to build TLB files by going to the project's properties in VS2005 -> Build -> Output -> Check "Register for COM interop". Also I have [assembly: ComVisible(true)] in the AssemblyInfo.cs.
Here's the summary of the source for the problem DLL and the DLL that it references for a return type:
using System;
using System.IO;
using System.Runtime.InteropServices;
using SymbolTable;
namespace ProblemLibrary
{
public class Foo
{
public Foo(string filename)
{
...
}
// method to read a text file into a SymbolTable
public SymbolTable BuildDataSet(string[] selected)
{
...
}
}
}
Here is a summary of SymbolTable.dll. It holds a return type that ProblemLibrary uses.
using System;
using System.Collections.Generic;
namespace SymbolTable
{
public class SymbolTable
{
readonly Dictionary<SymbolInfoStub, string> _symbols = new Dictionary<SymbolInfoStub, string>();
/*methods that interact with Dictionary snipped*/
}
}
回答1:
- You need to have ctor without any params.
- You should have GuidAttribute and ProgIdAttribute around the classes.
- Its better to mark the assembly as ComVisible(false) and mark explicitly the classes that need export.
- Use interfaces for your classes.
Make sure the you have GuidAttribute in the assembly level.
[Guid("<PUT-GUID-HERE-1>")] [ComVisible(true)] interface IFoo { void DoFoo(); } [Guid("<PUT-GUID-HERE-2>")] [ComVisible(true)] [ProgId("ProgId.Foo")] class Foo : IFoo { public void DoFoo() { } }
回答2:
I saw a similar problem. I got an error like:
warning MSB3391: does not contain any types that can be unregistered for COM Interop.
I followed all the rules (ComVisible, etc.) but nothing worked.
Solution: I had to put something in the default constructor so that it would not be optimized away. The moment I had something there, the registration finished with no message and the component was visible in the registry.
Interesting note: a friend of mine managed to register the original DLL with the empty default constructor on his machine (64-bit Windows-7, VS2008-Professional, like mine). However, his REGASM.EXE was:
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\regasm.exe
while mine was:
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\RegAsm.exe
So it could be some difference between versions of the .NET framework - maybe the later version is optimizing too much and the REGASM does not account for that.
回答3:
In the AssemblyInfo.cs file, make sure you have the following:
// Setting ComVisible to false makes the types in this assembly not visible
// to COM components. If you need to access a type in this assembly from
// COM, set the ComVisible attribute to true on that type.
[assembly: ComVisible(true)]
UPDATE:
Read: How can I make use of .NET objects from within Excel VBA?
Which links to: http://richnewman.wordpress.com/2007/04/15/a-beginner%E2%80%99s-guide-to-calling-a-net-library-from-excel/
来源:https://stackoverflow.com/questions/853553/warning-msb3391-dll-does-not-contain-any-types-that-can-be-unregistered-for-c