CODEWITHSUNDEEP
c#winformsentity-framework
Egor Kadochnikov
Egor Kadochnikov

Reputation: 41

How to combine multiple tables in one dataGridView using Entity Framework?

I have a Windows Forms application and want to get information from multiple tables of my database in the single dataGridView area.

I am trying to do it without SqlConnection and SqlDataAdapter, so the connection will be proceed through Entity Framework 

DBContext db = new DBContext

Is it possible to do so?

I have three tables:

User:

UserID,
Name

System:

SysID,
SysType

Activities:

ActivID,
UserID (FK)
SysID (FK)
Date,
Version,
Changes

My code:

using DBContext db = new DBCntext())
{
    dataGridView.DataSource = db.Table.ToList<Table>();
}

So I would write in case of only one table, but would it be possible to concatenate two or more tables without do it right in the database?

At the end I want to get User+System+Activities tables within one dataGridView.

Upvotes: 0

Views: 1124

Answers (1)

Steve Greene
Steve Greene

Reputation: 12304

If your class is properly defined like this: 

public class Activity
{
    public int ActivityID { get; set; }
    public string Version{ get; set; }
    public DateTime Date { get; set; }
    public string Changes { get; set; }

    public int UserID { get; set; }
    public User User { get; set; }  // navigation property for User
    public int SystemID { get; set; }
    public System System { get; set; }  // navigation property for System
}

Now you can write a query like:

using DBContext db = new DBCntext())
{
    dataGridView.DataSource = db.Activitys
        .Include(a => a.User)
        .Include(a => a.System)
        .Select(a => new MyModel {
            MyModel.ActivityID = a.ActivityID,
            MyModel.Version= a.Version,
            MyModel.Date = a.Date ,
            MyModel.Changes = a.Changes,
            MyModel.UserName = a.User.Name,
            MyModel.SysType= a.System.SysType
        })
        .ToList();
}

If you have not defined navigation properties, then you could use a LINQ Join.

Upvotes: 1

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