Passing a Command Parameter from a Datagrid through a Keybinding

Question

I've a wpf specific problem. I'm trying to delete a Row from a Datagrid, by defining a Keybinding that passes the selected Row of the Datagrid as a Commandparameter to a Command.

This is my Keybinding:

<UserControl.Resources >
    <Commands:CommandReference x:Key="deleteKey" Command="{Binding DeleteSelectedCommand}"/>
</UserControl.Resources>

<UserControl.InputBindings>
    <KeyBinding Key="D" Modifiers="Control" Command="{StaticResource deleteKey}"/>
</UserControl.InputBindings>

I know this basically works, because I can debug up to the DeleteSelectedCommand. However there flies an Exception because the DeleteSelectedCommand expectes a Row of the Datagrid to delete as Call Parameter.

How can I pass the SelectedRow through the Keybinding?

I want to do this only in the XAML, if possible, without changing the Code Behind.

Answer 1

Rather than trying to use a command parameter, create a property to store the selected row in:

private Model row;

 public Model Row
     {
         get { return row; }
         set
         {
             if (row != value)
             {
                 row = value;
                 base.RaisePropertyChanged("Row");
             }
         }
     }

where Model is the class of the objects your grid is displaying. Add the selectedItem property on the datagrid to use the property:

<DataGrid SelectedItem="{Binding Row, UpdateSourceTrigger=PropertyChanged}"/> 

then have your command pass through the row to the method:

    public ICommand DeleteSelectedCommand
     {
         get
         {
             return new RelayCommand<string>((s) => DeleteRow(Row));
         }
     }

and for your keybindings:

 <DataGrid.InputBindings>
            <KeyBinding Key="Delete" Command="{Binding DeleteSelectedCommand}" />
        </DataGrid.InputBindings>

Hope that helps!