Question

I am creating 2 projects that have the same database (it’s an MDF database). The first one is the map editor, and I use XNA 4 and Web Services to connect to it. The second one is the game itself and uses XNA 3.1 and Entity Data Model to connect database.

When I run the map editor and access the database, it runs properly. Bbut when I run the game and access the database, it shows an error “The underlying provider failed on Open”

I think the connection from the web service is not closed yet. But I don’t know where I should close the connection.

Here is my code from the web service:

public Map AddNewMap(string username, string mapName, int sizeX, int sizeY)
    {
        using (BaseModelDataContext context = new BaseModelDataContext())
        {
            Map newMap = new Map()
            {
                Username = username,
                Name = mapName,
                SizeX = sizeX,
                SizeY = sizeY,
                Upload_Date = DateTime.Now,
                Status = 0
            };

            context.Maps.InsertOnSubmit(newMap);
            context.SubmitChanges(System.Data.Linq.ConflictMode.FailOnFirstConflict);
            context.Dispose();
            return newMap;
        }
    }

EDIT:

Here is the entity data model code :

using (MazeEntities ent = new MazeEntities())
        {
            ent.Connection.Open();
            return (from map in ent.Map
                    select map).ToList<Map>();
        }

This code runs properly if I did not use the web service before. If I use the web service first, it shows an error at ent.Connection.Open();

Here is the inner exception:

Cannot open user default database. Login failed.\r\nLogin failed for user ‘erkape-PC\erkape’.

Connection string for web service :

connectionString=”Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\3DMapDatabase.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True”

Connection string for the game:

“metadata=res:///MazeDataModel.csdl|res:///MazeDataModel.ssdl|res://*/MazeDataModel.msl;provider=System.Data.SqlClient;provider connection string="Data Source=.\SQLEXPRESS;AttachDbFilename=D:\eRKaPe\DropBox\TA\Program\3D_Map_Editor\3DMapEditorServices\App_Data\3DMapDatabase.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True;MultipleActiveResultSets=True"” providerName=”System.Data.EntityClient” />

Answer 1

Finally I found a way to solve my problem after reading some articles.
The connection from the web service doesn’t close automatically after I close the map editor. That is why I can’t access my database from the game.
I have to change the connection string from both application, I set the User Instance to False. The game can access the database this way.