How to Bind Different Lists to DataGridComboBoxColumn in each row using MVVM

Question

I want to bind 'Units' property of ResultModel Class to DataGridComboBoxColumn. Other Bindings work fine but it cannot resolve 'Units' property. It recommends me 'Results' List instead of 'Units'. I want to use different Lists in each row.

You can see my View, ViewModel and Model Classes below.

View.xaml

<DataGrid x:Name="DataGrid" AutoGenerateColumns="False" Grid.Row="1" ItemsSource="{Binding Results}">
            <DataGrid.Columns>
                <DataGridTextColumn Header="#" Width="20" Binding="{Binding Path=Count}" />
                <DataGridTextColumn Header="Name" Width="*" Binding="{Binding Path=ComponentName}" />
                <DataGridTextColumn Header="Variable" Width="*" Binding="{Binding Path=Property}" />
                <DataGridTextColumn Header="Value" Width="*" Binding="{Binding Path=PropertyValue}" />
                <DataGridComboBoxColumn Header="Unit" Width="*" ItemsSource="{Binding Units}"/>
            </DataGrid.Columns>
</DataGrid>

ViewModel.cs

private List<ResultModel> _results;

public List<ResultModel> Results
        {
            get { return _results; }
            set
            {
                _results = value;
                RaisePropertyChanged("Results");
            }
        }

ResultModel.cs

private int _count;
        public int Count
        {
            get { return _count; }

            set { _count = value; RaisePropertyChanged("Count"); }
        }

        private string _componentName;
        public string ComponentName
        {
            get { return _componentName; }

            set { _componentName = value; RaisePropertyChanged("ComponentName"); }
        }

        private string _property;
        public string Property
        {
            get { return _property; }

            set { _property = value; RaisePropertyChanged("Property"); }
        }

        private double _propertyValue;
        public double PropertyValue
        {
            get { return _propertyValue; }

            set { _propertyValue = value; RaisePropertyChanged("PropertyValue"); }
        }

        private List<object> _units;
        public List<object> Units
        {
            get { return _units; }

            set { _units = value; RaisePropertyChanged("Units"); }
        }

        private Type _componentType;
        public Type ComponentType
        {
            get { return _componentType; }

            set { _componentType = value; RaisePropertyChanged("ComponentType"); }
        }

Answer 1

I had to use a DataGridTemplateColumn that contained a ComboBox to get it to work properly. This assumes the object in Units has a Name property to display, you should adjust DisplayMemberPath accordingly. You will pribably also want to bind SelectedItem to something, so you know what item they picked.

<DataGridTemplateColumn Header="Unit">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate DataType="local:ResultModel">
            <ComboBox
                DisplayMemberPath="Name"
                ItemsSource="{Binding Path=Units}" />
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

Answer 2

Try this:

<DataGridComboBoxColumn Header="Unit" Width="*">
    <DataGridComboBoxColumn.ElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding Units}" />
        </Style>
    </DataGridComboBoxColumn.ElementStyle>
    <DataGridComboBoxColumn.EditingElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding Units}" />
        </Style>
    </DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

You may also want to set the DisplayMemberPath property of the DataGridComboBoxColumn to the name of a property of the units.