ComboBox SelectedItem binding not updating

Question

I'm a bit puzzled: this works:

<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
            <Label Content="Rol" />
            <ComboBox ItemTemplate="{StaticResource listRollen}"
                      Height="23" Width="150"
                      SelectedItem="{Binding Path=SelectedRol, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
                      ItemsSource="{Binding Path=allRollen, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        </StackPanel>

and the property for SelectedRol is:

public TblRollen SelectedRol
    {
        get { return _selectedRol; }
        set
        {
            if (_selectedRol != value)
            {
                _selectedRol = value;
                OnPropertyChanged("SelectedRol");
            }
        }
    }

But this doesn't work:

<StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
            <Label Content="Soort" />
            <ComboBox ItemTemplate="{StaticResource listSoorten}"
                      Height="23" Width="150"
                      ItemsSource="{Binding Path=allSoorten}"
                      SelectedItem="{Binding Path=SelectedProduct, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
        </StackPanel>

with following property SelectedProduct:

public TblProduktSoorten SelectedProduct
    {
        get { return _selectedPSoort; }
        set
        {
            if (_selectedPSoort != value)
            {
                _selectedPSoort = value;
                OnPropertyChanged("SelectedProduct");
            }
        }
    }

somewhere in my code I set SelectedProduct = p.TblProduktSoorten and while debugging, I see the property gets set correctly...

Answer 1

Combobox inside a DataGrid?

If the combobox is in a DataGrid you must add this :

Mode=TwoWay, UpdateSourceTrigger=PropertyChanged

See this : https://stackoverflow.com/a/5669426/16940

Answer 2

This might be related to the fact that apparently attribute order does matter, in your second case the ItemsSource and SelectedItem declarations are swapped.