This question already has an answer here:
I am using a LINQ lambda expression like so:
int Value = 1; qryContent objContentLine; using (Entities db = new Entities()) { objContentLine = (from q in db.qryContents where q.LineID == Value orderby q.RowID descending select q).FirstOrDefault(); } However, I am getting the following error:
Cannot convert lambda expression to type 'string' because it is not a delegate type
I think you are missing using System.Linq; from this system class.
and also add using System.Data.Entity; to the code
In my case, I had to add using System.Data.Entity;
My case it solved i was using
@Html.DropDownList(model => model.TypeId ...) using
@Html.DropDownListFor(model => model.TypeId ...) will solve it
If it's not related to missing using directives stated by other users, this will also happen if there is another problem with your query.
Take a look on VS compiler error list : For example, if the "Value" variable in your query doesn't exist, you will have the "lambda to string" error, and a few errors after another one more related to the unknown/erroneous field.
In your case it could be :
objContentLine = (from q in db.qryContents where q.LineID == Value orderby q.RowID descending select q).FirstOrDefault(); Errors:
Error 241 Cannot convert lambda expression to type 'string' because it is not a delegate type
Error 242 Delegate 'System.Func<..>' does not take 1 arguments
Error 243 The name 'Value' does not exist in the current context
Fix the "Value" variable error and the other errors will also disappear.
For people just stumbling upon this now, I resolved an error of this type that was thrown with all the references and using statements placed properly. There's evidently some confusion with substituting in a function that returns DataTable instead of calling it on a declared DataTable. For example:
This worked for me:
DataTable dt = SomeObject.ReturnsDataTable(); List<string> ls = dt.AsEnumerable().Select(dr => dr["name"].ToString()).ToList<string>(); But this didn't:
List<string> ls = SomeObject.ReturnsDataTable().AsEnumerable().Select(dr => dr["name"].ToString()).ToList<string>(); I'm still not 100% sure why, but if anyone is frustrated by an error of this type, give this a try.