DataGrid row selection bug

Question

 I created WPF Application (VS 2010, .NET 4) project, you can reproduce this through copying a code into the corresponding files.

Code for MainWindow.xaml:

 

<
Window
 x:Class
=
"
WpfBadDataGridRowIsSelectedBinding.MainWindow
"

  xmlns
=
"
http://schemas.microsoft.com/winfx/2006/xaml/presentation
"

  xmlns:x
=
"
http://schemas.microsoft.com/winfx/2006/xaml
"
 Title
=
"
MainWindow
"
 Height
=
"
350
"
 Width
=
"
525
"

  ResizeMode
=
"
NoResize
"
>

 <
Grid
>

  <
DataGrid
 ItemsSource
=
"
{Binding List}
"
 AutoGenerateColumns
=
"
False
"
 SelectionMode
=
"
Extended
"
 IsReadOnly
=
"
True
"
>

   <
DataGrid.Columns
>

    <
DataGridTextColumn
 Width
=
"
*
"
 Header
=
"
Number
"
 Binding
=
"
{Binding Number, Mode=OneWay}
"
 />

    <
DataGridCheckBoxColumn
 Width
=
"
*
"
 Header
=
"
IsSelected
"
 Binding
=
"
{Binding IsSelected, Mode=TwoWay}
"
 />

   </
DataGrid.Columns
>


   <
DataGrid.RowStyle
>

    <
Style
 TargetType
=
"
DataGridRow
"
>

     <
Setter
 Property
=
"
IsSelected
"
 Value
=
"
{Binding IsSelected, Mode=TwoWay}
"
 />

    </
Style
>

   </
DataGrid.RowStyle
>

  </
DataGrid
>

 </
Grid
>

</
Window
>

 

Code for MainWindow.xaml.cs:

 

namespace
 WpfBadDataGridRowIsSelectedBinding
{
 using
 System.Collections;
 using
 System.Collections.ObjectModel;
 using
 System.ComponentModel;

 ///
 <summary>

 ///
 Interaction logic for MainWindow.xaml

 ///
 </summary>

 public
 partial
 class
 MainWindow
 {
  private
 readonly
 ObservableCollection<SimpleViewModel> list = new
 ObservableCollection<SimpleViewModel>();

  public
 MainWindow()
  {
   InitializeComponent();

   this
.DataContext = this
;

   for
 (var
 i = 0; i < 100; i++)
   {
    this
.list.Add(new
 SimpleViewModel(i));
   }
  }

  public
 IEnumerable List
  {
   get

   {
    return
 this
.list;
   }
  }

  private
 sealed
 class
 SimpleViewModel : INotifyPropertyChanged
  {
   private
 readonly
 int
 number;
   private
 bool
 isSelected;

   public
 SimpleViewModel(int
 number)
   {
    this
.number = number;
   }

   public
 int
 Number
   {
    get

    {
     return
 this
.number;
    }
   }

   public
 bool
 IsSelected
   {
    get

    {
     return
 this
.isSelected;
    }

    set

    {
     if
 (value == this
.isSelected)
     {
      return
;
     }

     this
.isSelected = value;

     this
.OnPropertyChanged("IsSelected"
);
    }
   }

   #region
 INotifyPropertyChanged Members

   public
 event
 PropertyChangedEventHandler PropertyChanged;

   private
 void
 OnPropertyChanged(string
 propertyName)
   {
    var
 handler = this
.PropertyChanged;

    if
 (handler != null
)
    {
     handler(this
, new
 PropertyChangedEventArgs(propertyName));
    }
   }

   #endregion

  }
 }
}

 

 

If I click the first row in DataGrid after run then the corresponding checkbox in the column "IsSelected" is checked, and this is OK. The checking works for second, third.. etc rows of the first page. The second page starts from the 15th row and there I have a problem. If I click row 20 the corresponding checkbox isn't checked, the same with row 21, 22 and so on. And if I scroll DataGrid to the end and return scrolling to row 0 then click the row I also don't see checked checkbox, and now this be on all rows in DataGrid.

What have I done wrong?

I doubt whether you have testers?

 

Answer 1

Interesting.

I think you should make the relative binding one way only(OneWay and OneWayToSource). It works when I changed your code to:

<DataGrid ItemsSource="{Binding List}" AutoGenerateColumns="False" SelectionMode="Extended" IsReadOnly="True" > <DataGrid.Columns> <DataGridTextColumn Width="*" Header="Number" Binding="{Binding Number, Mode=OneWay}" /> <DataGridCheckBoxColumn Width="*" Header="IsSelected" Binding="{Binding IsSelected, Mode=OneWay}" /> </DataGrid.Columns> <DataGrid.RowStyle> <Style TargetType="DataGridRow"> <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=OneWayToSource,UpdateSourceTrigger=PropertyChanged}" /> </Style> </DataGrid.RowStyle> </DataGrid>

Answer 2

Thank you, Rulin Hong, but I'am need TwoWay mode.

Answer 3

I retest it that it works for twoway if you set up UpdateSourceTrigger=PropertyChanged in

<

 

 

Style TargetType="DataGridRow">

 

 

 

<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />

Answer 4

Not completely correct. Select the row 0, then select row 1 with Ctrl, scroll to end, and select the row 99 without Ctrl, and now scroll to begin,

voila, the row 0 still selected...

Answer 5

And another code with slight modifications:

Code for MainWindow.xaml:

<Window x:Class="WpfBadDataGridRowIsSelectedBinding.MainWindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"
  ResizeMode="NoResize">
  <DockPanel LastChildFill="True">
    <StackPanel DockPanel.Dock="Top" Margin="5" Orientation="Horizontal">
      <Button Height="23" Content="Select" Click="Button_Click"/>
    </StackPanel>
    <DataGrid ItemsSource="{Binding List}" AutoGenerateColumns="False" SelectionMode="Extended" IsReadOnly="True">
      <DataGrid.Columns>
        <DataGridTextColumn Width="*" Header="Number" Binding="{Binding Number, Mode=OneWay}" />
        <DataGridCheckBoxColumn Width="*" Header="IsSelected" Binding="{Binding IsSelected, Mode=TwoWay}" />
      </DataGrid.Columns>

      <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
          <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
        </Style>
      </DataGrid.RowStyle>
    </DataGrid>
  </DockPanel>
</Window>

Code for MainWindow.xaml.cs:

namespace WpfBadDataGridRowIsSelectedBinding
{
  using System.Collections;
  using System.Collections.ObjectModel;
  using System.ComponentModel;

  /// <summary>
  /// Interaction logic for MainWindow.xaml
  /// </summary>
  public partial class MainWindow
  {
    private readonly ObservableCollection<SimpleViewModel> list = new ObservableCollection<SimpleViewModel>();

    public MainWindow()
    {
      InitializeComponent();

      this.DataContext = this;

      for (var i = 0; i < 100; i++)
      {
        this.list.Add(new SimpleViewModel(i));
      }
    }

    public IEnumerable List
    {
      get
      {
        return this.list;
      }
    }

    private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
    {
      for (var i = 0; i < list.Count; i += 2)
      {
        this.list[i].IsSelected = true;
      }
    }

    private sealed class SimpleViewModel : INotifyPropertyChanged
    {
      private readonly int number;
      private bool isSelected;

      public SimpleViewModel(int number)
      {
        this.number = number;
      }

      public int Number
      {
        get
        {
          return this.number;
        }
      }

      public bool IsSelected
      {
        get
        {
          return this.isSelected;
        }

        set
        {
          if (value == this.isSelected)
          {
            return;
          }

          this.isSelected = value;

          this.OnPropertyChanged("IsSelected");
        }
      }

      #region INotifyPropertyChanged Members

      public event PropertyChangedEventHandler PropertyChanged;

      private void OnPropertyChanged(string propertyName)
      {
        var handler = this.PropertyChanged;

        if (handler != null)
        {
          handler(this, new PropertyChangedEventArgs(propertyName));
        }
      }

      #endregion
    }
  }
}

Start the application, click button "Select", and scroll down, nice, huh?

If you replace the style DataGridRow to:

<Style TargetType="DataGridRow">
          <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        </Style>

So it will not change anything.

Answer 6

Hi Shuralex,

This problem is caused by the VisualizingStackPanel, set the VirtualizingStackPanel.IsVirtualizing as false will solve this problem.

Something likes the follows:

<DataGrid ItemsSource="{Binding List}" AutoGenerateColumns="False" SelectionMode="Extended" IsReadOnly="True" VirtualizingStackPanel.IsVirtualizing="False">

    <DataGrid.Columns>

        <DataGridTextColumn Width="*" Header="Number" Binding="{Binding Number, Mode=OneWay}" />

        <DataGridCheckBoxColumn Width="*" Header="IsSelected" Binding="{Binding IsSelected, Mode=TwoWay}" />

    </DataGrid.Columns>

    <DataGrid.RowStyle>

        <Style TargetType="DataGridRow">

            <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />

        </Style>

    </DataGrid.RowStyle>

</DataGrid>

Hope this helps.

Best regards,
Kevin Pan

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Answer 7

Hi Kevin,

Thank you, I know about it, it just slowly working on real data sources. Temporarily did. I am writing now, "DataGrid" based on
ListBox (selection there is OK)

Answer 8

I can't believe this. O.O Not the only one with a bug there.

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