"Type mismatch" error when calling a simple method in a c# assembly registered for COM interop

Question

I've build a classlibrary using c# and the .net framework 3.5. In my class library there is a class called Utilities with two methods.

public string Method1(int length)
{
}

public string Method2(int length, string aStringParameter)
{
}

Now I went and build a simple asp page calling my methods. Method1 work like a charm. Method2 causes a "Type Mismatch" error. What am I missing here?

Pls do provide details on how are you invoking the method? Are you invoking the C# assembly as an ActiveX Control ? — abhilash
– abhilash, Commented Mar 21, 2009 at 17:42
The error was on a stupidity on my side and ASP threw a type mismatch instead of a "Check your syntax, fool" error. What do I do now? Close this question? — Mats
– Mats, Commented Mar 22, 2009 at 9:19

Vinay · Accepted Answer · 2009-03-21 13:57:13Z

1

Try to put

  MarshalAs(UnmanagedType.BStr)

for string type that you are passing to method2.

Here is a detailed explanation.

answered Mar 21, 2009 at 13:57

Vinay

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