Exemplo n.º 1
0
        /// <summary>
        /// Intercept method calls
        /// </summary>
        /// <param name="myMessage">
        /// Contains information about the method being called
        /// </param>
        /// <returns>
        /// A <see cref="ReturnMessage"/>.
        /// </returns>
        public override IMessage Invoke(IMessage myMessage)
        {
            IMethodCallMessage callMessage = myMessage as IMethodCallMessage;

            if (null == callMessage)
            {
                Debug.WriteLine("Message type not implemented: " + myMessage.GetType().ToString());
                return(null);
            }

            MethodInfo method = callMessage.MethodBase as MethodInfo;

            if (null == method)
            {
                Debug.WriteLine("Unrecognized Invoke call: " + callMessage.MethodBase.ToString());
                return(null);
            }

            object returnValue = null;

            object[] outArgs      = null;
            int      outArgsCount = 0;

            string       methodName = method.Name;
            Type         returnType = method.ReturnType;
            BindingFlags flags      = BindingFlags.InvokeMethod;
            int          argCount   = callMessage.ArgCount;

            object invokeObject;
            Type   invokeType;
            Type   byValType;

            object[] args;
            object   arg;

            COMWrapper[] originalArgs;
            COMWrapper   wrapper;

            ParameterModifier[] argModifiers = null;
            ParameterInfo[]     parameters   = null;
            ParameterInfo       parameter;

            if ("Dispose" == methodName && 0 == argCount && typeof(void) == returnType)
            {
                this.Dispose();
            }
            else if ("ToString" == methodName && 0 == argCount && typeof(string) == returnType)
            {
                returnValue = this.ToString();
            }
            else if ("GetType" == methodName && 0 == argCount && typeof(System.Type) == returnType)
            {
                returnValue = this._InterceptType;
            }
            else if ("GetHashCode" == methodName && 0 == argCount && typeof(int) == returnType)
            {
                returnValue = this.GetHashCode();
            }
            else if ("Equals" == methodName && 1 == argCount && typeof(bool) == returnType)
            {
                returnValue = this.Equals(callMessage.Args[0]);
            }
            else if (1 == argCount && typeof(void) == returnType &&
                     (methodName.StartsWith("add_") || methodName.StartsWith("remove_")))
            {
                bool removeHandler = methodName.StartsWith("remove_");
                methodName = methodName.Substring(removeHandler ? 7 : 4);

                Delegate handler = callMessage.InArgs[0] as Delegate;
                if (null == handler)
                {
                    return(new ReturnMessage(new ArgumentNullException("handler"), callMessage));
                }

                try
                {
                    if (removeHandler)
                    {
                        RemoveEventHandler(methodName, handler);
                    }
                    else
                    {
                        AttachEventHandler(methodName, handler);
                    }
                }
                catch (Exception ex)
                {
                    return(new ReturnMessage(ex, callMessage));
                }
            }
            else
            {
                invokeObject = this._COMObject;
                invokeType   = this._COMType;

                if (methodName.StartsWith("get_"))
                {
                    // Property Get
                    methodName = methodName.Substring(4);
                    flags      = BindingFlags.GetProperty;
                    args       = callMessage.InArgs;
                }
                else if (methodName.StartsWith("set_"))
                {
                    // Property Set
                    methodName = methodName.Substring(4);
                    flags      = BindingFlags.SetProperty;
                    args       = callMessage.InArgs;
                }
                else
                {
                    args = callMessage.Args;
                    if (null != args && 0 != args.Length)
                    {
                        // Modifiers for ref / out parameters
                        argModifiers    = new ParameterModifier[1];
                        argModifiers[0] = new ParameterModifier(args.Length);

                        parameters = method.GetParameters();
                        for (int i = 0; i < parameters.Length; i++)
                        {
                            parameter = parameters[i];
                            if (parameter.IsOut || parameter.ParameterType.IsByRef)
                            {
                                argModifiers[0][i] = true;
                                outArgsCount++;
                            }
                        }

                        if (0 == outArgsCount)
                        {
                            argModifiers = null;
                        }
                    }
                }

                // Un-wrap wrapped COM objects before passing to the method
                if (null == args || 0 == args.Length)
                {
                    originalArgs = null;
                }
                else
                {
                    originalArgs = new COMWrapper[args.Length];
                    for (int i = 0; i < args.Length; i++)
                    {
                        if (null != args[i] && RemotingServices.IsTransparentProxy(args[i]))
                        {
                            wrapper = RemotingServices.GetRealProxy(args[i]) as COMWrapper;
                            if (null != wrapper)
                            {
                                originalArgs[i] = wrapper;
                                args[i]         = wrapper._COMObject;
                            }
                        }
                        else if (0 != outArgsCount && argModifiers[0][i])
                        {
                            byValType = GetByValType(parameters[i].ParameterType);
                            if (byValType.IsInterface)
                            {
                                // If we're passing a COM object by reference, and
                                // the parameter is null, we need to pass a
                                // DispatchWrapper to avoid a type mismatch exception.
                                if (null == args[i])
                                {
                                    args[i] = new DispatchWrapper(null);
                                }
                            }
                            else if (typeof(Decimal) == byValType)
                            {
                                // If we're passing a decimal value by reference,
                                // we need to pass a CurrencyWrapper to avoid a
                                // type mismatch exception.
                                // http://support.microsoft.com/?kbid=837378
                                args[i] = new CurrencyWrapper(args[i]);
                            }
                        }
                    }
                }

                try
                {
                    returnValue = invokeType.InvokeMember(methodName,
                                                          flags, null, invokeObject, args, argModifiers, null, null);
                }
                catch (Exception ex)
                {
                    return(new ReturnMessage(ex, callMessage));
                }

                // Handle enum and interface return types
                if (null != returnValue)
                {
                    if (returnType.IsInterface)
                    {
                        // Wrap the returned value in an intercepting COM wrapper
                        if (Marshal.IsComObject(returnValue))
                        {
                            returnValue = COMWrapper.Wrap(returnValue, returnType);
                        }
                    }
                    else if (returnType.IsEnum)
                    {
                        // Convert to proper Enum type
                        returnValue = Enum.Parse(returnType, returnValue.ToString());
                    }
                }

                // Handle out args
                if (0 != outArgsCount)
                {
                    outArgs = new object[args.Length];
                    for (int i = 0; i < parameters.Length; i++)
                    {
                        if (!argModifiers[0][i])
                        {
                            continue;
                        }

                        arg = args[i];
                        if (null == arg)
                        {
                            continue;
                        }

                        parameter = parameters[i];
                        wrapper   = null;

                        byValType = GetByValType(parameter.ParameterType);
                        if (typeof(Decimal) == byValType)
                        {
                            if (arg is CurrencyWrapper)
                            {
                                arg = ((CurrencyWrapper)arg).WrappedObject;
                            }
                        }
                        else if (byValType.IsEnum)
                        {
                            arg = Enum.Parse(byValType, arg.ToString());
                        }
                        else if (byValType.IsInterface)
                        {
                            if (Marshal.IsComObject(arg))
                            {
                                wrapper = originalArgs[i];
                                if (null != wrapper && wrapper._COMObject != arg)
                                {
                                    wrapper.Dispose();
                                    wrapper = null;
                                }

                                if (null == wrapper)
                                {
                                    wrapper = new COMWrapper(arg, byValType);
                                }
                                arg = wrapper.GetTransparentProxy();
                            }
                        }

                        outArgs[i] = arg;
                    }
                }
            }

            return(new ReturnMessage(returnValue,
                                     outArgs, outArgsCount,
                                     callMessage.LogicalCallContext,
                                     callMessage));
        }
Exemplo n.º 2
0
 public static IField WrapField(object fieldToWrap)
 {
     return(COMWrapper.Wrap <IField>(fieldToWrap));
 }