How to access count property of a dynamic type in C# 4.0?
I have the follow method that returns a dynamic object representing an IEnumerable<'a> ('a=anonymous type) :
public dynamic GetReportFilesbyStoreProductID(int StoreProductID)
{
Report report = this.repository.GetReportByStoreProductID(StoreProductID);
if (report == null || report.ReportFiles == null)
{
return null;
}
var query = from x in report.ReportFiles
orderby x.DisplayOrder
select new { ID = x.RptFileID, Description = x.LinkDescription, File = x.LinkPath, GroupDescription = x.ReportFileGroup.Description };
return query;
}
I want to be able to access the Count property of this IEnumerable anonymous type. I'm trying to access the above method using the following code and it is failing:
dynamic Segments = Top20Controller.GetReportFilesbyStoreProductID(StoreProductID");
if (Segments.Count == 0) // <== Fails because object doesn't contain count.
{
...
}
dynamic keyword operate? Count property of the IEnumerable anonymous type? IEnumerable<myObject> instead of dynamic ? I'd prefer to not do that if I can as this method is only called in one place and creating a throw-away object seems like overkill.
The IEnumerable<T> that's returned from that method doesn't have a Count property, so I don't know what you're talking about. Maybe you forgot to write ToList() on the end to reify it into a list, or you meant to call the Count() method on IEnumerable<T> ?
You'll need to explicitly call Enumerable.Count().
IEnumerable<string> segments =
from x in new List<string> { "one", "two" } select x;
Console.WriteLine(segments.Count()); // works
dynamic dSegments = segments;
// Console.WriteLine(dSegments.Count()); // fails
Console.WriteLine(Enumerable.Count(dSegments)); // works
See Extension method and dynamic object in c# for a discussion of why extension methods aren't supported by dynamic typing.
(The "d" prefix is just for the example code - please do not use Hungarian notation!)
Update: Personally I'd go with @Magnus's answer of using if (!Segments.Any()) and return IEnumerable<dynamic> .
Count() needs to enumerate to complete collection, you probably want:
if (!Segments.Any())
{
}
And your function should return IEnumerable<object> instead of dynamic