Compare two List and Insert Delete record in database using Entity Framework in ASP.Net

Hi mahesh213,

Check this example. Now please take its reference and correct your code.

Code

protected void Page_Load(object sender, EventArgs e)
{
    TestEntities entities = new TestEntities();
    int mId = 1;
    var list2 = new List<Task>();
    list2.Add(new Task { OperationID = 1, MachineID = 1, Id = 1 });
    list2.Add(new Task { OperationID = 3, MachineID = 1, Id = 3 });
    list2.Add(new Task { OperationID = 5, MachineID = 1, Id = 4 });

    var list1 = entities.DownloadTasks.Where(x => x.MachineId == mId).ToList();

    foreach (Task task in list2)
    {
        var exists = list1.Where(x => x.OperationId == task.OperationID).FirstOrDefault();
        if (exists == null)
        {
            DownloadTask dtask = new DownloadTask();
            dtask.Id = task.Id;
            dtask.MachineId = task.MachineID;
            dtask.OperationId = task.OperationID;
            entities.DownloadTasks.Add(dtask);
            entities.SaveChanges();
        }
    }

    var updatedlist1 = entities.DownloadTasks.Where(x => x.MachineId == mId).ToList();
    foreach (DownloadTask task in updatedlist1)
    {
        var exists = list2.Where(x => x.OperationID == task.OperationId).FirstOrDefault();
        if (exists == null)
        {
            entities.DownloadTasks.Remove(task);
            entities.SaveChanges();
        }
    }

}

public class Task
{
    public int MachineID { get; set; }
    public int OperationID { get; set; }
    public int Id { get; set; }
}

Output