MVVM datagrid binding

Question

I'm using MVVM for my project and I'm trying to bind a table from my database with a DataGrid. But when I run my application datagrid is empty.

MainWindow.xaml.cs:

 public MainWindow(){
        InitializeComponent(); 
        DataContext = new LecturerListViewModel()
    }

MainWindow.xaml:

 <DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Source=Lecturers}" >
            <DataGrid.Columns>
                <DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
                <DataGridTextColumn Header="Surname" Binding="{Binding Surname}"/>
                <DataGridTextColumn Header="Phone" Binding="{Binding Phone_Number}" />
            </DataGrid.Columns>
 </DataGrid>

LecturerListViewModel.cs:

public class LecturerListViewModel : ViewModelBase<LecturerListViewModel> 
{

    public ObservableCollection<Lecturer> Lecturers;
    private readonly DataAccess _dataAccess = new DataAccess();

    public LecturerListViewModel()
    {
        Lecturers = GetAllLecturers();
    }

and ViewModelBase implements INotifyPropertyChanged.

Lecturer.cs

public class Lecturer
{
    public Lecturer(){}

    public int Id_Lecturer { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public string Phone_Number { get; set; }

What did I do wrong? I checked it with debuger and DataContext contains all lecturers, but ther aren't shown in datagrid.

kmatyaszek · Accepted Answer · 2012-11-08T21:23:36.413

10

You have an error in binding. Try this:

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Lecturers}" >

Code-behind:

private ObservableCollection<Lecturer> _lecturers = new ObservableCollection<Lecturer>();
public ObservableCollection<Lecturer> Lecturers
{
   get { return _lecturers; }
   set { _lecturers = value; }
}

Here is simple example code (LecturerSimpleBinding.zip).

edited Nov 08 '12 at 21:23

answered Nov 08 '12 at 19:59

kmatyaszek

19,016
9
60
65

Still not working. But now there are only headers in datagrid, with my solution I had at least empty rows – pawel1708hp Nov 08 '12 at 20:04
Thank you so much, it works. Here was the problem: //public ObservableCollection Lecturers; private ObservableCollection _lecturers = new ObservableCollection(); public ObservableCollection Lecturers { get { return _lecturers; } set { _lecturers = value; } } – pawel1708hp Nov 08 '12 at 20:18
ohh.. yeah, I focused on binding errors and I forgot how you create this ObservableCollection. – kmatyaszek Nov 08 '12 at 20:21
@kmatyaszek Thanks for the sample you provided +1 for that, If I want to bind click events from the form to my VIEWMODEL, How can I do that in a way that the selectedIndex/ select row id is provided to my viewmodel – Arijit Mukherjee Jun 16 '14 at 07:14
@ArijitMukherjee you can create in vm property `SelectedLecturer` (type of `Lecturer`) and binding to `DataGrid.SelectedItem`: ``, this solution should solve your problem. – kmatyaszek Jun 16 '14 at 20:10

score 8 · Answer 2 · answered Nov 08 '12 at 20:23

Here we go

 <DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Path=Lecturers}" >

Then

private ObservableCollection<Lecturer> lecturers;

public ObservableCollection<Lecturer> Lecturers
{
    get { return lecturers; }
    set
    {
        lecturers = value;
        this.NotifyPropertyChanged("Lecturers");
    }
}

score 6 · Answer 3 · answered Nov 09 '12 at 02:35

Sayed Saad above is correct. I see two potential problems with your setup, both of which Sayed resolves.

The example posted in the question doen not implement INotifyPropertyChanged
The CLR property being bound to must be a PUBLIC PROPERTY. Fields will not work, as databindindg works via reflection.

score 2 · Answer 4 · answered Nov 08 '12 at 20:18

2

Lecturers is a field, but data binding works with properties only. Try declaring Lecturers like:

public ObservableCollection<Lecturer> Lecturers { get; set; }

answered Nov 08 '12 at 20:18

skink

5,133
6
37
58

score 1 · Answer 5 · edited May 23 '17 at 11:48

MainWindow.xaml.cs: OK

MainWindow.xaml: OK

LecturerListViewModel.cs: OK - assuming that GetAllLecturers() method returns an ObservableCollection of Lecturer.

Lecturer.cs:

public class Lecturer : INotifyPropertyChanged
{
    //public Lecturer(){} <- not necessary

    private int _id;
    public int Id 
    {
        get { return _id; }
        set
        {
            _id = value;
            OnPropertyChanged("Id");
        }
    }
    // continue doing the above property change to all the properties you want your UI to notice their changes.

    ...

    public event PropertyChangedEventHandler PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Check this answer: Adding INotifyPropertyChanged to Model?

MVVM datagrid binding

5 Answers5

Linked