CODEWITHSUNDEEP
c#.netasp.net
user266003
user266003

Reputation:

Check for null value

 var entries = from video in Video.GetTopVideos().AsEnumerable()
                      select
                      new XElement("item",
                          new XElement("title", video.Title),
                          new XElement("category", video.Tags[video.Tags.Count-1].Name),
                          //...........

If the property video.Tags==null then an exception throws. Can I check for null value?

Upvotes: 0

Views: 629

Answers (3)

Jim Mischel
Jim Mischel

Reputation: 134125

Yes, you can:

var entries = from video in Video.GetTopVideos().AsEnumerable()
                      where video.Tags != null
                      select
                      new XElement("item",
                          new XElement("title", video.Title),
                          new XElement("category", video.Tags[video.Tags.Count-1].Name),
                          //...........

Or, if you want to make sure that you always have something even if the Tags property is null:

var entries = from video in Video.GetTopVideos().AsEnumerable()
   let cat = (video.Tags != null && video.Tags.Count > 0) ? video.Tags[video.Tags.Count-1].Name : "**No Category**
   select
   new XElement("item",
       new XElement("title", video.Title),
       new XElement("category", cat),
       //...........

Upvotes: 2

Anthony Pegram
Anthony Pegram

Reputation: 126972

Yes, you can. You can rewrite that line as 

video.Tags != null ? new XElement(...) : null

If Tags is null, no XElement will be emitted for category in your resulting XML. You could, of course, elect to provide another default element instead of null, if you wish.

Upvotes: 2

Dave Brace
Dave Brace

Reputation: 1809

Add a where clause that states:

where video.Tags != null

This will limit your results to only those that do have Tags.

Your query will ultimately look like the following:

var entries = from video in Video.GetTopVideos().AsEnumerable()
              where video.Tags != null
              select  new XElement("item",
                      new XElement("title", video.Title),
                      new XElement("category", video.Tags[video.Tags.Count-1].Name),
                      //...........

Upvotes: 0

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