Question

Why EF can’t translate Int32.Parse in where condition section?

For example below code has error :

var query = (from list in dbContext.Packages
                             where list.Id == Int32.Parse(Request["Id"].ToString())
                             select list).FirstOrDefault();

I solved this problem :

Int32 ID = Int32.Parse(Request["Id"].ToString());
 var query = (from list in dbContext.Packages
                             where list.Id == ID
                             select list).FirstOrDefault();

Answer 1

Because the query is simply an Expression that gets translated into SQL.

EF doens’t know how to translate Int32.Parse into an equivalent SQL statement, so it fails.