Simple way to display row numbers on WPF DataGrid

I just want to display row numbers in the left-most column of my DataGrid. Is there some attribute to do this?

Keep in mind, this isn't a primary key for my table. I don't want these row numbers to move with their rows when a column is sorted. I basically want a running count开发者_开发技巧. It doesn't even need to have a header.

One way is to add them in the LoadingRow event for the DataGrid

<DataGrid Name="DataGrid" LoadingRow="DataGrid_LoadingRow" ...

void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
    e.Row.Header = (e.Row.GetIndex()).ToString(); 
}

When items are added or removed from the source list then the numbers can get out of sync for a while. For a fix to this, see the attached behavior here:
WPF 4 DataGrid: Getting the Row Number into the RowHeader

Useable like this

<DataGrid ItemsSource="{Binding ...}"
          behaviors:DataGridBehavior.DisplayRowNumber="True"> 

Adding a short info about Fredrik Hedblad answer.

<DataGrid Name="DataGrid" LoadingRow="DataGrid_LoadingRow" ...

void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
    e.Row.Header = (e.Row.GetIndex()+1).ToString(); 
}

...If you want to start numbering from 1

If your data grid has its ItemsSource bound to a collection, bind the AlternationCount property of your data grid to either the the count property of your collection, or to the Items.Count property of your DataGrid as follows:

<DataGrid ItemsSource="{Binding MyObservableCollection}" AlternationCount="{Binding MyObservableCollection.Count}" />

Or:

<DataGrid ItemsSource="{Binding MyObservableCollection}" AlternationCount="{Binding Items.Count, RelativeSource={RelativeSource Self}" />

Either should work.

Then, assuming you're using a DataGridTextColumn for your leftmost column you do the following in your DataGrid.Columns definition:

<DataGrid.Columns>
   <DataGridTextColumn Binding="{Binding AlternationIndex, RelativeSource={RelativeSource AncestorType=DataGridRow}}"
</DataGrid.Columns>

If you don't want to start at 0, you can add a converter to your binding to increment the index.

It's an old question, but I would like to share something. I had a similar problem, all I needed was a simple RowHeader numeration of rows and Fredrik Hedblad's answer was almost complete for my problem.

While this is great:

<DataGrid Name="DataGrid" LoadingRow="DataGrid_LoadingRow" ...

void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
    e.Row.Header = (e.Row.GetIndex()).ToString(); 
}

my headers messed up when removing and adding items. If you have buttons responsible for that just add dataGrid.Items.Refresh(); under the 'deleting' code as in my case:

private void removeButton_Click(object sender, RoutedEventArgs e)
{
    // delete items

    dataGrid.Items.Refresh();
}

That solved desyncronized numeration for me, because refreshing items calls DataGrig_LoadingRow again.

And just to add to the discussion on this... (I spent too much time finding this out!).

You'll need to set the EnableRowVirtualization to False on the datagrid to prevent errors in the row sequencing:

EnableRowVirtualization="False"

The EnableRowVirtualization property is set to true by default. When the EnableRowVirtualization property is set to true, the DataGrid does not instantiate a DataGridRow object for each data item in the bound data source. Instead, the DataGrid creates DataGridRow objects only when they are needed, and reuses them as much as it can. MSDN Reference here

Just another answer to provide almost copy&paste example (not to be encouraged) for new people or people in a rush, inspired by answers inside this post by @GrantA and @Johan Larsson ( + many other people who answered to the numerous posts on that subject)

• You may not want to add the enumeration inside a column

• You do not need to re-create your own Attached Property

  <UserControl...
  
  <Grid>
      <DataGrid ItemsSource="{Binding MainData.ProjColl}" 
                AutoGenerateColumns="False"
                AlternationCount="{ Binding MainData.ProjColl.Count}" >
          <DataGrid.Columns>
              <!--Columns given here for example-->
              ...
              <DataGridTextColumn Header="Project Name" 
                                  Binding="{Binding CMProjectItemDirName}"
                                  IsReadOnly="True"/>
              ...
              <DataGridTextColumn Header="Sources Dir" 
                                  Binding="{Binding CMSourceDir.DirStr}"/>
              ...
          </DataGrid.Columns>
  
          <!--The problem of the day-->
          <DataGrid.RowHeaderStyle>
              <Style TargetType="{x:Type DataGridRowHeader}">
                  <Setter Property="Content" 
                   Value="{Binding Path=(ItemsControl.AlternationIndex),
                   RelativeSource={RelativeSource AncestorType=DataGridRow}}"/>
              </Style>
          </DataGrid.RowHeaderStyle>
      </DataGrid>
  </Grid>
  
  </UserControl>
  

Note the parenthesis () around (ItemsControl.AlternationIndex) as warned in Fredrik Hedblad answer in Check if Row as odd number

After some Tests withRowHeaderStyle, the repaired and extended sample from NGI:

        <DataGrid EnableRowVirtualization="false" ItemsSource="{Binding ResultView}" AlternationCount="{Binding ResultView.Count}" RowHeaderWidth="10">
            <DataGrid.RowHeaderStyle>
                <Style TargetType="{x:Type DataGridRowHeader}">
                    <Setter Property="Content" Value="{Binding Path=AlternationIndex, RelativeSource={RelativeSource AncestorType=DataGridRow}}" />
                </Style>
            </DataGrid.RowHeaderStyle>
        </DataGrid>

Using attached properties, full source here.

using System.Windows;
using System.Windows.Controls;

public static class Index
{
    private static readonly DependencyPropertyKey OfPropertyKey = DependencyProperty.RegisterAttachedReadOnly(
        "Of",
        typeof(int),
        typeof(Index),
        new PropertyMetadata(-1));

    public static readonly DependencyProperty OfProperty = OfPropertyKey.DependencyProperty;

    public static readonly DependencyProperty InProperty = DependencyProperty.RegisterAttached(
        "In",
        typeof(DataGrid),
        typeof(Index),
        new PropertyMetadata(default(DataGrid), OnInChanged));

    public static void SetOf(this DataGridRow element, int value)
    {
        element.SetValue(OfPropertyKey, value);
    }

    public static int GetOf(this DataGridRow element)
    {
        return (int)element.GetValue(OfProperty);
    }

    public static void SetIn(this DataGridRow element, DataGrid value)
    {
        element.SetValue(InProperty, value);
    }

    public static DataGrid GetIn(this DataGridRow element)
    {
        return (DataGrid)element.GetValue(InProperty);
    }

    private static void OnInChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var row = (DataGridRow)d;
        row.SetOf(row.GetIndex());
    }
}

Xaml:

<DataGrid ItemsSource="{Binding Data}">
    <DataGrid.RowStyle>
        <Style TargetType="{x:Type DataGridRow}">
            <Setter Property="dataGrid2D:Index.In" 
                    Value="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}" />
        </Style>
    </DataGrid.RowStyle>

    <DataGrid.RowHeaderStyle>
        <Style TargetType="{x:Type DataGridRowHeader}">
            <Setter Property="Content" 
                    Value="{Binding Path=(dataGrid2D:Index.Of), 
                                    RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}}" />
        </Style>
    </DataGrid.RowHeaderStyle>
</DataGrid>