Combobox display value in Silverlight

Question

I have a ComboBox with CheckBoxes for items. When the user checks or deselects the checkboxes, I want the selected values ​​to appear in ContentPresenter, separated by a comma. Currently, I have redefined ContentPresenter:

<ContentPresenter x:Name="ContentPresenter"
    HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
    Margin="{TemplateBinding Padding}"
    VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
    ContentTemplate="{StaticResource SelectedOperationsText}"/>

ContentPresenter is by default part of the ComboBox style. Any tips on how to implement this feature?

ComboBox ItemTemplate is implemented as follows:

<DataTemplate x:Key="ComboItemTemplate">
     <Grid HorizontalAlignment="Left">
         <CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Text}"/>
     </Grid>
</DataTemplate>

Answer 1

This solution is not ideal (for example, you can create your own control template for management, inherited from combobox), but it works.

• Xaml

  <my:MyComboBox Width="180" ItemsSource="{Binding TestItems}" Text="{Binding SelectedItemsText}">
      <my:MyComboBox.ItemTemplate>
          <DataTemplate>
              <Grid HorizontalAlignment="Left">
                  <CheckBox IsChecked="{Binding IsChecked, Mode=TwoWay}" Content="{Binding Text}"/>
              </Grid>
          </DataTemplate>
      </my:MyComboBox.ItemTemplate>
  </my:MyComboBox>
  

• Hack combo box:

  public class MyComboBox : ComboBox
  {
  private ContentPresenter selectedContent;
  
  
  public MyComboBox()
  {
      this.DefaultStyleKey = typeof(ComboBox);
  }
  
  
  public override void OnApplyTemplate()
  {
      this.selectedContent = this.GetTemplateChild("ContentPresenter") as ContentPresenter;
      this.RefreshContent();
      base.OnApplyTemplate();
      this.SelectionChanged += (s, e) =>
          {
              //Cancel selection
              this.SelectedItem = null;
              this.RefreshContent();
          };
  }
  
  
  public string Text
  {
      get { return (string)GetValue(TextProperty); }
      set { SetValue(TextProperty, value); }
  }
  
  
  public static readonly DependencyProperty TextProperty =
      DependencyProperty.Register("Text", typeof(string), typeof(MyComboBox), 
      new PropertyMetadata(null, new PropertyChangedCallback((s,e)=>((MyComboBox)s).RefreshContent())));
  
  
  private void RefreshContent()
  {
      if (this.selectedContent != null)
      {
          var tb = (TextBlock)this.selectedContent.Content;
          tb.Text = this.Text;
      }
  }
  }
  

• MainViewModel

  public class MainViewModel : INotifyPropertyChanged
  {
  public MainViewModel()
  {
      this.InitializeTestItems();
  }
  
  
  public void InitializeTestItems()
  {
      this.TestItems = new List<TestItemModel>{
                  new TestItemModel{IsChecked=true, Text="first"},
                  new TestItemModel{IsChecked=false, Text="second"},
                  new TestItemModel{IsChecked=false, Text="third"}};
      this.RefreshSelectedItemsText();
      foreach (var item in this.TestItems)
          item.CheckChanged += (s, e) => this.RefreshSelectedItemsText();
  }
  
  
  private void RefreshSelectedItemsText()
  {
      SelectedItemsText = string.Join(", ", this.TestItems.Where(ti => ti.IsChecked).Select(ti => ti.Text));
  }
  
  
  public List<TestItemModel> TestItems { get; set; }
  
  
  private string selectedItemsText;
  
  
  public string SelectedItemsText
  {
      get { return selectedItemsText; }
      set
      {
          selectedItemsText = value;
          OnPropertyChanged("SelectedItemsText");
      }
  }
  }
  

4.ItemViewModel

public class TestItemModel
{
    private bool isChecked;

    public bool IsChecked
    {
        get { return isChecked; }
        set 
        { 
            isChecked = value;
            if (CheckChanged != null)
                CheckChanged(this, null);
        }
    }

    public string Text { get; set; }

    public event EventHandler<EventArgs> CheckChanged;
}

Answer 2

, "ContentPresenter".

combox, , , ( SO):

ComboBox, TextBlock. ItemTemplate ComboBox Checked UnChecked. Text TextBlock, . XAML:

<Grid Name="LayoutRoot">
    <ComboBox ItemsSource="{Binding Path=SitesList}" Name="CBsites" DropDownOpened="ComboBox_DropDownOpened" DropDownClosed="ComboBox_DropDownClosed">
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <CheckBox Content="{Binding Path=Location}" Checked="SiteCheckBox_Checked" Unchecked="SiteCheckBox_Unchecked" />
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>
    <TextBlock Name="TXTselected" IsHitTestVisible="False" VerticalAlignment="Center" Margin="6,0,0,0" />
</Grid>

, TextBlock. , .

Answer 3

codeplex: codeplex, , , .. , - ...

I prefer not to need a boolean in related data, so I cited bindable SelectedItems