WPF MVVM - ComboBox binding selected value

Question

EDIT
Solution was actually a proper setting of SelectedItem , SelectedValue and SelectedValuePath properties.

<ComboBox
         Grid.Column="1"
         Padding="5"
         DisplayMemberPath="PositionName"
         IsSynchronizedWithCurrentItem="False"
         ItemsSource="{Binding Positions, Mode=OneWay}"
         SelectedItem="{Binding SelectedOperatorPosition, Mode=TwoWay, 
         UpdateSourceTrigger=PropertyChanged}"
         SelectedValue="{Binding SelectedOperatorPosition.PositionName}"
         SelectedValuePath="PositionName" />

QUESTION I am trying to bind ComboBox SelectedValue with DataGrid SelectedItem using MVVM pattern.
ComboBox ItemSource is Shifts property. I want it's SelectedValue to be bound with SelectedShift property, which is updated each time user selects another OperatorModel from DataGrid.
Although SelectedOperator setter sets SelectedShift value to SelectedOperator.Shift , ComboBox doesn't get updated.

View
Debugging ViewModel Property setter

My ViewModel:

private Operator selectedOperator;

public Operator SelectedOperator
{
    get
    {
        return selectedOperator;
    }
    set
    {
        selectedOperator = value;
        if (selectedOperator != null)
        {
            SelectedShift = selectedOperator.Shift;
        }
        OnPropertyChanged(nameof(SelectedOperator));
    }
}

private Shift selectedShift;

public Shift SelectedShift
{
    get
    {
        return selectedShift;
    }
    set
    {
        selectedShift = value;
        OnPropertyChanged(nameof(SelectedShift));
    }
}

XAML:

<ComboBox
         Grid.Column="1"
         Padding="5"
         DisplayMemberPath="Name"
         ItemsSource="{Binding Shifts}"
         SelectedValue="{Binding SelectedShift}"
         SelectedValuePath="Name" />

Answer 1

我认为你应该使用 SelectedItem="{Binding SelectedShift}