private static MethodRecognitionResult TryCallMethod(MethodInfo method, Type[] typeArguments, Expression[] positionalArguments, IDictionary <string, Expression> namedArguments)
{
var parameters = method.GetParameters();
int castCount = 0;
if (parameters.Length < positionalArguments.Length)
{
return(null);
}
var args = new Expression[parameters.Length];
Array.Copy(positionalArguments, args, positionalArguments.Length);
int namedArgCount = 0;
for (int i = positionalArguments.Length; i < args.Length; i++)
{
if (namedArguments?.ContainsKey(parameters[i].Name) == true)
{
args[i] = namedArguments[parameters[i].Name];
namedArgCount++;
}
else if (parameters[i].HasDefaultValue)
{
castCount++;
args[i] = Expression.Constant(parameters[i].DefaultValue, parameters[i].ParameterType);
}
else
{
return(null);
}
}
// some named arguments were not used
if (namedArguments != null && namedArgCount != namedArguments.Count)
{
return(null);
}
int automaticTypeArgs = 0;
// resolve generic parameters
if (method.ContainsGenericParameters)
{
var typeArgs = new Type[method.GetGenericArguments().Length];
if (typeArguments != null)
{
if (typeArguments.Length > typeArgs.Length)
{
return(null);
}
Array.Copy(typeArguments, typeArgs, typeArgs.Length);
}
for (int i = 0; i < typeArgs.Length; i++)
{
if (typeArgs[i] == null)
{
// try to resolve from arguments
var arg = Array.FindIndex(parameters, p => p.ParameterType.IsGenericParameter && p.ParameterType.GenericParameterPosition == i);
automaticTypeArgs++;
if (arg >= 0)
{
typeArgs[i] = args[arg].Type;
}
else
{
return(null);
}
}
}
method = method.MakeGenericMethod(typeArgs);
parameters = method.GetParameters();
}
else if (typeArguments != null)
{
return(null);
}
// cast arguments
for (int i = 0; i < args.Length; i++)
{
var casted = TypeConversion.ImplicitConversion(args[i], parameters[i].ParameterType);
if (casted == null)
{
return(null);
}
if (casted != args[i])
{
castCount++;
args[i] = casted;
}
}
return(new MethodRecognitionResult
{
CastCount = castCount,
AutomaticTypeArgCount = automaticTypeArgs,
Method = method,
Arguments = args
});
}
public CastedExpressionBindingProperty ConvertExpressionToType(ParsedExpressionBindingProperty expr, ExpectedTypeBindingProperty expectedType = null) => new CastedExpressionBindingProperty(TypeConversion.ImplicitConversion(expr.Expression, expectedType?.Type ?? typeof(object), throwException: true, allowToString: true));
