MVVM WPF ComboBox with CheckBox

Question

I've tried to search for this for quite some time and haven't found results that help. (perhaps my google-foo needs work?) I'm also fairly new to WPF MVVM, so there is a lot I'm still learning.

My Question is actually in two parts... Firstly, I have a Combobox that has Checkboxes within them within a View. Code:

 <ComboBox Grid.Column="0"
                      Grid.ColumnSpan="5"
                      Margin="15,0,0,0"
          ItemsSource="{Binding StaffNames}" 
                      SelectedValue="{Binding SelectedStaffNames}"
          Grid.Row="4">
                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <CheckBox Content="{Binding Path=FullName}"
                                  VerticalAlignment="Center"
                                  IsChecked="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type ComboBoxItem}},     Path=IsSelected,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"
                                  Command="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window},
                            Path=DataContext.CheckBoxSelected}"
                                  Margin="3">  
                        </CheckBox>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>

Everytime I check a checkbox, it seems that the checkboxes get automatically unchecked.

My ViewModel code is as follows.

private bool _isSelected;
        public bool IsSelected
        {
            get
            {
                return _isSelected;
            }
            set
            {
                _isSelected = value;
                RaisePropertyChanged("IsSelected");
            }
        }

What is wrong here?

My second question is: Once the above is resolved, I need to append all checked names (staff names in this case) to a list and pass the values back to a separate view/view model.

I'm at a complete loss for how to accomplish this. Any help or suggestions would be greatly appreciated.

Thanks :)

Answer 1

2 things that could be going wrong

1. Are you trying to set the check box value in your command - "DataContext.CheckBoxSelected"? Since you already have a binding, this could be resetting the value.

2. Clicking the checkbox does not update selected item in combo box but only updates the checkbox.