Image cropper doesn't work within nested foreach - umbraco7

Question

I have a problem in Umbraco 7. I'm using a nested Multiple Node Tree Picker, but the GetCropUrl doesn't work. The crop function is ok, I've already used it.
#{
if (CurrentPage.HasValue("artists"))
{
var artistList = CurrentPage.artists.ToString().Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
var artistCollection = Umbraco.Content(artistList);
foreach (var artist in artistCollection)
{
if (artist.HasValue("coverImages"))
{
var coverImagesList = artist.coverImages.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
var coverImagesCollection = Umbraco.Media(coverImagesList);
foreach (var coverImage in coverImagesCollection.RandomOrder().Take(1).Where("Visible"))
{
<img src="#coverImage.GetCropUrl(305, 195)"/>
}
}
}
}
}
Update:
I changed the code and I started to use Id.
When I use this:
foreach (var coverImage in coverImagesCollection)
<p>#coverImage.Id</p>
<img src="#Umbraco.TypedMedia(1105).Url"/>
}
I got back the the image id from #coverImage.Id, and the image is working.
When I use this:
foreach (var coverImage in coverImagesCollection)
<img src="#Umbraco.TypedMedia(coverImage.Id).Url"/>
}
The image is still good.
After I'm cropping with fix id.
foreach (var coverImage in coverImagesCollection)
<img src="#Umbraco.TypedMedia(1105).GetCropUrl(305, 195)"/>
}
Working, but then:
foreach (var coverImage in coverImagesCollection)
<img src="#Umbraco.TypedMedia(coverImage.Id).GetCropUrl(305, 195)"/>
}
I got an error:
'Umbraco.Web.Models.PublishedContentBase' does not contain a definition for 'GetCropUrl'
How is that possible?

Answer 1

I've got an answer from Umbraco forum. He said coverImage.Id is dynamic, so I need to try this, and it worked perfectly:
foreach (var coverImage in coverImagesCollection)
<img src="#Umbraco.TypedMedia((int)coverImage.Id).GetCropUrl(305, 195)"/>
}