How To Use Entity Data Model In Class Library

Question

I was successfully able to save data to the Sql Server database, using an Entity Data Model, as follows:

MEDIANEntities db = new MEDIANEntities();
tblCountry objTable = new tblCountry();
objTable.Name= txtName.Text.Trim();
objTable.CreatedDate = System.DateTime.Now;
db.AddTotblCountries(objTable);
db.SaveChanges();

The idea now, is to use the EDM in a class library, so that it can be consumed in other projects (a tier architecture basically). I have created a Class library - 'MedianContext' and then created a new edmx file inside it - 'MedianModel'. And then another class library - 'MedianDAL'. Added the reference of MedianContext to it.

Unable to access properties of objcontext and tb. How can I proceed further. If it helps, when adding the reference to MedianDAL, the MediaContext.dll was inside the debug folder instead of Release folder, as seen in many examples.

enter image description here

Using LinqToEntities, I need to first create an object, right?So I did that - objContext...Should I need to add any more references,namespaces — Ruby
– Ruby, Commented Oct 24, 2013 at 13:36

Tobias · Accepted Answer · 2013-10-24 13:57:22Z

1

Have you tried it with Linq2Entities?
e.g.:

try
{
    using (var medianEntities = new MedianModel.MEDIANEntities())
    {
          //Do any LinqToEntity-Expressions
    }
}
catch(Exception)
{ 
    //ErrorHandling
}

That works for me. I also have my .edmx files in a different project and just added a reference to this.

Edit:

Of course you have to put this code into a method-body.
Here is a simple example:

public List<Map> GetAllMaps()
{
    var Maps = new System.Collections.Generic.List<Map>();

    try
    {
         using (var mapEntities = new Model.MapEntities())
         {
              var MyMaps= (from M in mapEntities.Maps
                               orderby M.Description
                               select M.MapID, M.Description);

             foreach (var Map in MyMaps)
             {
                   Maps.Add(Map);
             }
          }
          return Maps;
      }
      catch (System.Exception Exc)
      {
          Log.Err(string.Format("Error: {0}", Exc));
          throw new System.Exception(Exc.ToString());
      }
}

edited Oct 24, 2013 at 13:57

answered Oct 24, 2013 at 13:41

Tobias

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2 Comments

Ruby Over a year ago

Putting it into a method worked. I could access the object properties now, even without 'using'. Thank you very much.

Tobias Over a year ago

Glad to help you. You should take a look at LinqToEntities, in my opinion it's not hard to understand and quite good to handle.

Georgi-it · Accepted Answer · 2013-10-24 13:12:17Z

0

Probably because you are trying to access the properties while in the context of the class ? Create constructor for this class and access the properties from there:

public Test
{
tb....
}

answered Oct 24, 2013 at 13:12

Georgi-it

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