I am porting http://customfeedaggregator.codeplex.com/ to c#, to make myself think in C# and WPF.
I am stuck on an issue in IEnumerable
.
There's a class - blogpost.vb
'Represents a single blog post
Class BlogPost
Private _title As String
Private _datePublished As DateTime
Private _url As Uri
Private _category As String
Property Title() As String
Get
Return _title
End Get
Set(ByVal value As String)
_title = value
End Set
End Property
Property DatePublished() As DateTime
Get
Return _datePublished
End Get
Set(ByVal value As DateTime)
_datePublished = value
End Set
End Property
Property Url() As Uri
Get
Return _url
End Get
Set(ByVal value As Uri)
_url = value
End Set
End Property
Property Category() As String
Get
Return _category
End Get
Set(ByVal value As String)
_category = value
End Set
End Property
End Class
and a shared function that retrieves feeds and converts them to blogposts.
Shared Function RetrieveFeeds(ByVal Address As String) As IEnumerable(Of BlogPost)
Dim doc As XDocument = XDocument.Load(Address)
Dim query = From item In doc...<item> _
Let DataPubblicazione = CDate(item.<pubDate>.Value).ToLocalTime _
Let TitoloPost = item.<title>.Value _
Let Url = item.<link>.Value _
Let Categoria = item.<category>.Value _
Order By DataPubblicazione Descending _
Select New BlogPost With _
{.DatePublished = DataPubblicazione, .Title = EscapeXml(TitoloPost), _
.Url = New Uri(Url), .Category = Categoria}
Return query
End Function
The class is a standard, so that wasn't an issue. But the RetreiveFeeds
is being difficult.
Here's my C# version:
public static IEnumerable<BlogPost> RetrieveFeeds(string Address)
{
XDocument doc = XDocument.Load(Address);
var query = from item in doc.Descendants("item")
let DataPubblicazione = Convert.ToDateTime(item.Attribute("pubDate").Value)
let TitoloPost = item.Attribute("title").Value
let Url = item.Attribute("link").Value
let Categoria = item.Attribute("category").Value
orderby DataPubblicazione descending
select new BlogPost {DataPubblicazione , EscapeXML(TitoloPost), Url, Categoria};
return query;
}
The error shown at the part where it says Select New Blogpost is:
Cannot initialize type 'FeedMe.BlogPost' with a collection initializer because it does not implement 'System.Collections.IEnumerable'.
So, do I need to explicitly implement IEnumerable in my dataclass? or is my C# Port code wrong? Is this a difference between VB.net and C#?
Actually the correct syntax is very similar between C# and VB.NET:
Original C#:
select new BlogPost {DataPubblicazione , EscapeXML(TitoloPost),
Url, Categoria};
Corrected C#:
select new BlogPost {DatePublished = DataPubblicazione ,
Title = EscapeXML(TitoloPost),
Url = new Uri(Url),
Category = Categoria};
Original VB.NET:
Select New BlogPost With _
{.DatePublished = DataPubblicazione, .Title = EscapeXml(TitoloPost), _
.Url = New Uri(Url), .Category = Categoria}
When declaring a new BlogPost
with an object initializer you need to name the parameters.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.