private static async Task <IQueryable> InvokeOperation(
object instanceImplementMethod, MethodInfo method, object[] parameters, IEdmModel model)
{
object result = method.Invoke(instanceImplementMethod, parameters);
var returnType = method.ReturnType;
if (returnType == typeof(void))
{
return(null);
}
var task = result as Task;
if (task != null)
{
await task;
if (returnType.GenericTypeArguments.Any())
{
returnType = returnType.GenericTypeArguments.First();
var resultProperty = typeof(Task <>).MakeGenericType(returnType).GetProperty("Result");
result = resultProperty.GetValue(task);
}
else
{
return(null);
}
}
IEdmTypeReference edmReturnType = returnType.GetReturnTypeReference(model);
if (edmReturnType.IsCollection())
{
var elementClrType = returnType.GetElementType() ??
returnType.GenericTypeArguments[0];
if (result == null)
{
return(ExpressionHelpers.CreateEmptyQueryable(elementClrType));
}
var enumerableType = result.GetType().FindGenericType(typeof(IEnumerable <>));
if (enumerableType != null)
{
return(((IEnumerable)result).AsQueryable());
}
// Should never hint this path, add here to make sure collection result will not hint single result part
return(ExpressionHelpers.CreateEmptyQueryable(elementClrType));
}
// This means this is single result
// cannot return new[] { result }.AsQueryable(); as need to return in its own type but not object type
var objectQueryable = new[] { result }.AsQueryable();
var castMethodInfo = typeof(Enumerable).GetMethod("Cast").MakeGenericMethod(returnType);
var castedResult = castMethodInfo.Invoke(null, new object[] { objectQueryable });
var typedQueryable = ExpressionHelperMethods.QueryableAsQueryable
.Invoke(null, new object[] { castedResult }) as IQueryable;
return(typedQueryable);
}