Binding class with master/detail into two datagridview

Question

I had made a class in C# Windows form to represent my database. It has a master/detail using List<>

A record with Employee profile with Trainings(master) and TrainingDetails(detail)

Now, how can I display this into 2 datagridview that whenever I select a "Training" from the first datagridview it will display the details on the 2nd datagridview.

Its easy to change the datasource of the 2nd datagridview whenever the user select a new item from the first datagridview. But im wondering how it is done professionally.

Also saving is a pain, Im thingking to iterate through the datarow and save it but It mean I have to know what are the data has been update, inserted and deleted.

Please help me. Im a newbie.

Answer 1

BindingSources take care of this for you.

For example say I have two classes, Teachers and Students:

public class Teacher
{
    private List<Student> _students = new List<Student>();
    public string Name { get; set; }
    public string Class { get; set; }
    public List<Student> Students { get { return _students; } }
}

public class Student
{
    public string Name { get; set; }
    public int Age { get; set; }
}

You can then create a list of Teachers which represents the Master/Detail situation:

List<Teacher> teachers = new List<Teacher>();
Teacher t = new Teacher();
t.Name = "Mr. Smith";
t.Class = "A1";
teachers.Add(t);

Student s = new Student();
s.Name = "Jimmy Jones";
s.Age = 6;            
t.Students.Add(s);

s = new Student();
s.Name = "Jane Doe";
s.Age = 5;
t.Students.Add(s);

t = new Teacher();
t.Name = "Ms. Allen";
t.Class = "B3";
teachers.Add(t);

s = new Student();
s.Name = "Sally Student";
s.Age = 7;
t.Students.Add(s);

On my form I have two DataGridViews, teachersDataGridView and studentsDataGridView and two binding sources teachersBindingSource and studentsBindingSource.

I wire everything up like so:

    teachersBindingSource.DataSource = teachers;

    studentsBindingSource.DataSource = teachersBindingSource;
    studentsBindingSource.DataMember = "Students";

    teachersDataGridView.DataSource = teachersBindingSource;
    studentsDataGridView.DataSource = studentsBindingSource;

And as if by magic when running up on the form selecting an item from the teachers grid changes students grid.

---

For managing inserts, updates and deletes you will need to implement some sort of change tracking yourself (or use an ORM such as Entity Framework or nHibernate). It is a topic that deserves its own question so read up on those technologies (and look at the blog post I like below) and come back when you have some specific problems.

---

For this answer I borrowed heavily from this excellent post - the example I've given is complete and avoids a lot of the complexity in that authors example's, but eventually you will probably want to at least know about everything he discusses. Download his demos and have a look.