CODEWITHSUNDEEP
c#asp.netweb-serviceslinq-to-sql
user3671271
user3671271

Reputation: 568

How to return linq to sql query result in web service asp.net?

I'm beginner in web service and want to write simple query with LINQ to SQL and return that query result with Web Service,write this code:

[WebMethod]
public  string LinqExample()
{
    string conn = "Data Source=REMOVETHIS";
    DataClasses1DataContext behzad = new DataClasses1DataContext(conn);
    string result;
    var query = (from p in behzad.CDRTABLEs
                 where p.name == "behzad".Trim()
                 select p).Take(1);

    return query.ToString();
}

But when I run that web service,I get this error:

enter image description here

How can I solve that?

Upvotes: 0

Views: 692

Answers (1)

Markus Weninger
Markus Weninger

Reputation: 12648

Three things:

1.) It seems your connection string is wrong, because there is a problem establishing the connection, not executing the query.

2.) You should not use Take(1), which returns an IEnumerable, but FirstOrDefault. You use Take if you want to take the first n elements, but First or FirstOrDefault if you only want exactly one result element.

3.) If using FirstOrDefault so, you have to do a null-check on returning: return query == null ? "" : query.ToString()

Upvotes: 1

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