C# – Could not find an implementation of the query ‘Select’ not found

cdatabaselinq

My error is:

Could not find an implementation of the query pattern for source type
'System.Data.Entity.Database'. 'Select' not found.

My relevent code is:

DatabaseEntities db = new DatabaseEntities();   
var whichUi = from UiType in db.Database
              select  AdvancedUi;

I am using the linq import (common answer on other threads).

Best Answer

I think your error is that you try to select something from .Database directly, not from the table. Instead of this code:

from UiType in db.Database

try out something like this:

from UiType in db.UiTypes
select UiType.AdvancedUi;

This should work as the table UiTypes will implemet the IEnumerable interface.

You should put your table name after the in keyword.
UiType is just a placeholder, and can be anything you want. Please, pay attention to the select clause - you must use the placeholder there, not the table name.

Related Solutions

C# – Create Generic method constraining T to an Enum

Since Enum Type implements IConvertible interface, a better implementation should be something like this:

public T GetEnumFromString<T>(string value) where T : struct, IConvertible
{
   if (!typeof(T).IsEnum) 
   {
      throw new ArgumentException("T must be an enumerated type");
   }

   //...
}

This will still permit passing of value types implementing IConvertible. The chances are rare though.

C# – How to return NULL from a generic method in C#

Two options:

Return default(T) which means you'll return null if T is a reference type (or a nullable value type), 0 for int, '\0' for char, etc. (Default values table (C# Reference))
Restrict T to be a reference type with the where T : class constraint and then return null as normal

Best Answer

Related Solutions

C# – Create Generic method constraining T to an Enum

C# – How to return NULL from a generic method in C#

Related Topic