LINQ to JSON: InvalidOperationException: Lambda Parameter not in scope

问题

I am trying the execute the sample code of LINQ to JSON (mentioned below) but it is giving me following error

Stack Trace:

[InvalidOperationException: Lambda Parameter not in scope]

Code I am executing is:

      JObject rss =
          new JObject(

                new JProperty("id", "James Newton-King"),
                new JProperty("name", "http://james.newtonking.com"),
                new JProperty("data", "James Newton-King's blog."),
                new JProperty("children",
                  new JArray(
                    from p in mwsysbot.Software
                    where p.SoftwareName == name
                    select new JObject(                            
                      new JProperty("id",p.SoftwareUUID),
                      new JProperty("name", p.SoftwareName)         
                    )
                  )
                 )
               );

Also when I remove line "new JProperty("name", p.SoftwareName) " the code executes perfectly.

Why?

回答1:

I tried this and it worked for me...

     IQueryable<Software> soft = (from s in mwsysbot.Software
                                                     select s).ToList();

JObject rss =
           new JObject(
                     new JProperty("id", "James Newton-King"),
                     new JProperty("name", "http://james.newtonking.com"),
                     new JProperty("data", "James Newton-King's blog."),
                     new JProperty("children", new JArray(
                         from m in soft
                         select new JObject(
                             new JProperty("id",m.SoftwareName),
                             new JProperty("name", m.SoftwareName),
                             new JProperty("children",new JArray())
                             )
                         ))


             );

I dont know the reason !

Is it like we can use only the "List " data structure in the above place ?

回答2:

Linq could try to lazy-load the SoftwareName. Try using a DTO and eager-load the parameter name before creating the new object.

来源：https://stackoverflow.com/questions/998772/linq-to-json-invalidoperationexception-lambda-parameter-not-in-scope