CA2205: Use managed equivalents of Win32 API


For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

Breaking ChangeNon Breaking

A platform invoke method is defined and a method with the equivalent functionality exists in the .NET Framework class library.

A platform invoke method is used to call an unmanaged DLL function and is defined using the System.Runtime.InteropServices.DllImportAttribute attribute, or the Declare keyword in Visual Basic. An incorrectly defined platform invoke method can lead to runtime exceptions because of issues such as a misnamed function, faulty mapping of parameter and return value data types, and incorrect field specifications, such as the calling convention and character set. If available, it is generally simpler and less error prone to call the equivalent managed method than to define and call the unmanaged method directly. Calling a platform invoke method can also lead to additional security issues that need to be addressed.

To fix a violation of this rule, replace the call to the unmanaged function with a call to its managed equivalent.

Suppress a warning from this rule if the suggested replacement method does not provide the needed functionality.

The following example shows a platform invoke method definition that violates the rule. In addition, the calls to the platform invoke method and the equivalent managed method are shown.

using System;
using System.Runtime.InteropServices;
using System.Text;

namespace UsageLibrary
   internal class NativeMethods
      private NativeMethods() {}

      // The following method definition violates the rule.
      [DllImport("kernel32.dll", CharSet = CharSet.Unicode, 
          SetLastError = true)]
      internal static extern int ExpandEnvironmentStrings(
         string lpSrc, StringBuilder lpDst, int nSize);

   public class UseNativeMethod
      public void Test()
         string environmentVariable = "%TEMP%";
         StringBuilder expandedVariable = new StringBuilder(100);

         // Call the unmanaged method.

         // Call the equivalent managed method.

CA1404: Call GetLastError immediately after P/Invoke

CA1060: Move P/Invokes to NativeMethods class

CA1400: P/Invoke entry points should exist

CA1401: P/Invokes should not be visible

CA2101: Specify marshaling for P/Invoke string arguments