Interoperability Warnings

  • Article

Note

This article applies to Visual Studio 2015. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

Interoperability warnings support interaction with COM clients.

In This Section

Rule Description
CA1400: P/Invoke entry points should exist A public or protected method is marked by using the System.Runtime.InteropServices.DllImportAttribute attribute. Either the unmanaged library could not be located or the method could not be matched to a function in the library.
CA1401: P/Invokes should not be visible A public or protected method in a public type has the System.Runtime.InteropServices.DllImportAttribute attribute (also implemented by the Declare keyword in Visual Basic). Such methods should not be exposed.
CA1402: Avoid overloads in COM visible interfaces When overloaded methods are exposed to COM clients, only the first method overload retains its name. Subsequent overloads are uniquely renamed by appending to the name an underscore character (_) and an integer that corresponds to the order of declaration of the overload.
CA1403: Auto layout types should not be COM visible A COM-visible value type is marked by using the System.Runtime.InteropServices.StructLayoutAttribute attribute set to LayoutKind.Auto. The layout of these types can change between versions of the .NET Framework, which will break COM clients that expect a specific layout.
CA1404: Call GetLastError immediately after P/Invoke A call is made to the Marshal.GetLastWin32Error method or the equivalent Win32 GetLastError function, and the immediately previous call is not to a platform invoke method.
CA1405: COM visible type base types should be COM visible A COM-visible type derives from a type that is not COM-visible.
CA1406: Avoid Int64 arguments for Visual Basic 6 clients Visual Basic 6 COM clients cannot access 64-bit integers.
CA1407: Avoid static members in COM visible types COM does not support static methods.
CA1408: Do not use AutoDual ClassInterfaceType Types that use a dual interface enable clients to bind to a specific interface layout. Any changes in a future version to the layout of the type or any base types will break COM clients that bind to the interface. By default, if the ClassInterfaceAttribute attribute is not specified, a dispatch-only interface is used.
CA1409: Com visible types should be creatable A reference type that is specifically marked as visible to COM contains a public parameterized constructor but does not contain a public default (parameterless) constructor. A type without a public default constructor is not creatable by COM clients.
CA1410: COM registration methods should be matched A type declares a method that is marked by using the System.Runtime.InteropServices.ComRegisterFunctionAttribute attribute but does not declare a method that is marked by using the System.Runtime.InteropServices.ComUnregisterFunctionAttribute attribute, or vice versa.
CA1411: COM registration methods should not be visible A method that is marked by using the System.Runtime.InteropServices.ComRegisterFunctionAttribute attribute or the System.Runtime.InteropServices.ComUnregisterFunctionAttribute attribute is externally visible.
CA1412: Mark ComSource Interfaces as IDispatch A type is marked by using the System.Runtime.InteropServices.ComSourceInterfacesAttribute attribute, and at least one of the specified interfaces is not marked by using the System.Runtime.InteropServices.InterfaceTypeAttribute attribute set to ComInterfaceType.InterfaceIsIDispatch.
CA1413: Avoid non-public fields in COM visible value types Nonpublic instance fields of COM-visible value types are visible to COM clients. Review the content of the fields for information that should not be exposed, or that will have unintended design or security effects.
CA1414: Mark boolean P/Invoke arguments with MarshalAs The Boolean data type has multiple representations in unmanaged code.
CA1415: Declare P/Invokes correctly This rule looks for platform invoke method declarations that target Win32 functions that have a pointer to an OVERLAPPED structure parameter and the corresponding managed parameter is not a pointer to a System.Threading.NativeOverlapped structure.