WPF: Setting the text alignment of a GridViewColumn

By default, text is centered in the headers of a ListView (not in the content cells!), I've been struggling to make it left aligned, here's what I've come up with:

<ListView.Resources>
    <DataTemplate x:Key="Templ">
       <TextBlock HorizontalAlignment="Left" Text="{Binding}"/>
    </DataTemplate>
</ListView.Resources>   
...
<GridViewColumn HeaderTemplate="{StaticResource Templ}">File</GridViewColumn>

This does seem to be the right place to alter the appearance of the header, since I can change other properties like Margin, etc., yet it does not respond to the HorizontalAlignment property! I'm guessing the textbox is sized to content and itself开发者_开发百科 centered, thus making the alignment property redundant.

How can I make the text left aligned ?

Set the HeaderContainerStyle to a style that sets HorizontalContentAlignment to left:

<ListView.Resources>
    <DataTemplate x:Key="Templ">
        <TextBlock HorizontalAlignment="Left" Text="{Binding}"/>
    </DataTemplate>
    <Style x:Key="HeaderStyle" TargetType="GridViewColumnHeader">
        <Setter Property="HorizontalContentAlignment" Value="Left"/>
    </Style>
</ListView.Resources>
<ListView.View>
    <GridView>
        <GridView.Columns>
            <GridViewColumn HeaderTemplate="{StaticResource Templ}" HeaderContainerStyle="{StaticResource HeaderStyle}">File</GridViewColumn>
        </GridView.Columns>
    </GridView>
</ListView.View>

Here's an attached property for setting the header's content alignment:

    #region HeaderContentAlignment

    /// <summary>Gets a <see cref="GridViewColumn"/>'s header content alignment.</summary>
    [Category("Common")]
    [AttachedPropertyBrowsableForType(typeof(GridViewColumn))]
    public static HorizontalAlignment GetHeaderContentAlignment(GridViewColumn gridViewColumn)
    {
        return (HorizontalAlignment)gridViewColumn.GetValue(HeaderContentAlignmentProperty);
    }
    /// <summary>Sets a <see cref="GridViewColumn"/>'s header content alignment.</summary>
    public static void SetHeaderContentAlignment(GridViewColumn gridViewColumn, HorizontalAlignment value)
    {
        gridViewColumn.SetValue(HeaderContentAlignmentProperty, value);
    }

    /// <summary>Indicates a <see cref="GridViewColumn"/>'s <see cref="GridViewColumn.HeaderContainerStyle"/>.</summary>
    public static readonly DependencyProperty HeaderContentAlignmentProperty = 
        DependencyProperty.RegisterAttached(
            "HeaderContentAlignment",
            typeof(HorizontalAlignment), // type
            typeof(GridViewExtensions), // containing static class
            new PropertyMetadata(HorizontalAlignment.Center, OnHeaderContentAlignmentChanged)
            );

    private static void OnHeaderContentAlignmentChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        OnHeaderContentAlignmentChanged((GridViewColumn)d, (HorizontalAlignment)e.NewValue);
    }

    private static void OnHeaderContentAlignmentChanged(GridViewColumn gridViewColumn, HorizontalAlignment alignment)
    {
        Style style;
        if (ColumnHeaderAlignments.TryGetValue(alignment, out style) == false)
        {// style NOT created -> create, cache
            style = new Style(typeof(GridViewColumnHeader));
            style.Setters.Add(new Setter(Control.HorizontalContentAlignmentProperty, alignment));
            ColumnHeaderAlignments.Add(alignment, style);
        }
        gridViewColumn.HeaderContainerStyle = style;
    }

    /// <summary>cache [HorizontalAlignment]: [Style]</summary>
    static readonly Dictionary<HorizontalAlignment, Style> ColumnHeaderAlignments = new Dictionary<HorizontalAlignment, Style>(4);

    #endregion HeaderContentAlignment

This may help someone else, as i was struggling too, the best way is to define style for GridViewColumn.

You can set a style to apply to all column headers like below

<GridView>
  <GridView.ColumnHeaderContainerStyle>
      <Style TargetType="{x:Type GridViewColumnHeader}">
        <Setter Property="HorizontalContentAlignment" Value="Left" />
      </Style>
   </GridView.ColumnHeaderContainerStyle>
</GridView>

and You can override the header style for a specific column like below:

<GridViewColumn Header="Something">
   <GridViewColumn.HeaderContainerStyle>
    <Style TargetType="{x:Type GridViewColumnHeader}">
        <Setter Property="HorizontalContentAlignment" Value="Left" />
    </Style>
   </GridViewColumn.HeaderContainerStyle>
</GridViewColumn>