CODEWITHSUNDEEP
c#wpfmvvm
Yulian Linev
Yulian Linev

Reputation: 15

Which button is clicked DataTemplate WPF MVVM

my question here is how to know which button is clicked. My buttons are bound to property of type ObservableCollection which contains objects of type Item and I need to use that object in my ViewModel when a button is clicked. Any ideas how to know which button is clicked? I had few ideas, like sending multiple Command Parameters (1.SelectedItems from ListBox 2.The Object from the button) or bind the object from the button to another property of type Item in the ViewModel after the button is clicked in order to use it. Any ideas will be apreciated.

I have this DataTemplate for buttons

<DataTemplate x:Key="ButtonTemplate">
            <WrapPanel>
                <Button x:Name="OrderButton"
                        FontSize="10"
                        Height="80" Width="80"
                        Content="{Binding Name}"
                        Command="{Binding OrderCommand, 
                                          Source={StaticResource OrderViewModel}}"
                        CommandParameter="{Binding ElementName=ListBoxUserControl, Path=SelectedItems}">
                </Button>
            </WrapPanel>
</DataTemplate>

My ViewModel

public class OrderViewModel : ObservableCollection<Order>, INotifyPropertyChanged
{ 
   public CreateOrderCommand CreateOrderCommand { get; set; }
   public ObservableCollection<Item> Data { get; set; }

 public OrderViewModel()
    {
        this.CreateOrderCommand = new CreateOrderCommand(this);
        DataObservableCollection data= new DataObservableCollection();
        Data = data;
    }
}

And I populate my buttons like this

<WrapPanel x:Name="OrderButtons">
            <ItemsControl   ItemTemplate="{StaticResource ButtonTemplate}"
                            ItemsSource="{Binding Data, Source={StaticResource OrderViewModel}}">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <WrapPanel Orientation="Horizontal">
                        </WrapPanel>
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
            </ItemsControl>
    </WrapPanel>

Upvotes: 0

Views: 1222

Answers (2)

altohr
altohr

Reputation: 11

First send the Button DataContext using the CommandParameter. To send the SelectedItem of your Listbox you can use 

<Listbox SelectedItem="{Binding SelectedItem}"/>

in your Listbox and make a SelectedItem property in your ViewModel. 

private YourItemObject mySelectedItem;
    public YourItemObject SelectedItem
    {
        get { return mySelectedItem; }

        set
        {
             value = mySelectedItem
        }

Now you can use the SelectedItem in your ViewModel when the Button gets clicket. If you have multiple selections it gets a little bit more tricky ;).

private ButtonClicked(Parameter object)
{
   SelectedItem.UsingIt();
   if(object is YourButtonDataContext){
        YourButtonDataContext.UsingIt();
   }
}

Update with MultiSelection:

With Multiselection you have to do your own Listbox. 

public class CustomListBox : ListBox
{
    public CustomListBox()
    {
        this.SelectionChanged += CustomListBox_SelectionChanged;
    }

    void CustomListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        this.SelectedItemsList = this.SelectedItems;
    }
    #region SelectedItemsList

    public IList SelectedItemsList
    {
        get { return (IList)GetValue(SelectedItemsListProperty); }
        set { SetValue(SelectedItemsListProperty, value); }
    }



    public static readonly DependencyProperty SelectedItemsListProperty =
            DependencyProperty.Register("SelectedItemsList", typeof(IList), typeof(CustomListBox), new PropertyMetadata(null));


    #endregion
}

In the ViewModel you have to have a property with the SelectedItems.

private IList mySelectedData = new List<SelectedDataObject>();
    public IList SelectedData
    {
        get { return mySelectedData ; }

        set
        {
            if (mySelectedData != value)
            {
                mySelectedData = value;
                RaisePropertyChanged(() => SelectedData);
            }
        }
    }

The XAML Looks like this:

<local:CustomListBox ItemsSource="{Binding YourList}" SelectionMode="Extended" SelectedItemsList="{Binding SelectedData, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
    ...
</local:CustomListBox>

Source for Multiselection in DataGrid is: https://stackoverflow.com/a/22908694/3330227

Upvotes: 1

ibebbs
ibebbs

Reputation: 2003

Simply change the Button.CommandParameter binding to CommandParamter="{Binding}" if you want the data context of the button (i.e. the item from your items source) as the command parameter or, CommandParameter="{Binding RelativeSource={RelativeSource Self}}" if you want the actual button that was clicked.

Upvotes: 1

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