private static MethodInfo ResolveMethod <TService>(Expression operation, out Action callback, out object[] args)
{
if (operation == null)
{
throw new ArgumentNullException("operation");
}
var lambda = operation as LambdaExpression;
if (lambda == null)
{
throw new ArgumentException("LambdaExpression expected", "operation");
}
if (lambda.Parameters.Count != 1 || lambda.Parameters[0].Type != typeof(TService))
{
throw new ArgumentException("The lambda was expected to take a single argument of type " + typeof(TService));
}
var call = lambda.Body as MethodCallExpression;
if (call == null || call.Object != lambda.Parameters[0])
{
throw new ArgumentNullException("Methods must invoked directly on the supplied service instance");
}
args = new object[call.Arguments.Count];
object[] argsCpy = args; // used for capture
ParameterInfo[] parameters = call.Method.GetParameters();
callback = null;
for (int i = 0; i < args.Length; i++)
{
if (parameters[i].ParameterType.IsByRef)
{
FieldInfo field;
object target;
if (!TryResolveField(call.Arguments[i], out field, out target))
{
throw new InvalidOperationException("Cannot guarantee ref/out behaviour due to expression complexity; consider simplifying the expression.");
}
args[i] = RpcUtils.IsRequestArgument(parameters[i]) ? field.GetValue(target) : null;
int iCpy = i; // for capture
callback += delegate { field.SetValue(target, argsCpy[iCpy]); };
}
else
{
args[i] = Evaluate(call.Arguments[i]);
}
}
return(call.Method);
}
