问罗伯特·吉塞克的非管理出口条件

EN

        'VBA7    
        Private Declare PtrSafe Function Command Lib "External.dll" (ByVal CommandName As String, ByVal Result As LongPtr, ByRef ResultLength As Long) As Long
        'VBA pre7
            Private Declare Function Command Lib "External.dll" (ByVal CommandName As String, ByVal Result As Long, ByRef ResultLength As Long) As Long

'Example to use.
'Result will be up to "i" characters - no new string involved
            Dim i As Long, x As Long, strResult As String
            i = 100
            strResult = Space(i)
            x = Command(CommandName, Arguments, StrPtr(strResult), i)

    [DllExport("Command", CallingConvention.StdCall)]
    public static int Command(string commandName, string arguments, IntPtr result, out /*or ref*/ int resultLength)
{
       string inputStr = Marshal.PtrToStringUni(result); //Unicode
       resultLength = inputStr.Length;
       int x = MainFunc.Command(commandName, arguments, ref inputStr);
       if(null == inputStr)
       {
            inputStr = "";
       }
       if(inputStr.Length > resultLength)
       {
            inputStr = inputStr.Substring(0, resultLength);
        }
        byte[] outputBytes = Encoding.Unicode.GetBytes(inputStr);
        Marshal.Copy(outputBytes, 0, result, outputBytes.Length);
        resultLength = inputStr.Length;
        return x;
    }