/// <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));
}
public static IField WrapField(object fieldToWrap)
{
return(COMWrapper.Wrap <IField>(fieldToWrap));
}