I've found the perfect solution, based on an answer by xr280xr. It works out of the box, in any condition, and without using additional code.
The style, that I put in <DataGrid.Resources>
:
<Style TargetType="{x:Type DataGridCell}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridCell}">
<TextBlock Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content.Text}" TextTrimming="CharacterEllipsis">
<TextBlock.ToolTip>
<ToolTip Visibility="{Binding RelativeSource={RelativeSource Self}, Path=PlacementTarget, Converter={StaticResource TrimToVisConverter}}">
<ToolTip.Content>
<TextBlock Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content.Text}"/>
</ToolTip.Content>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
The source of Converter={StaticResource TrimToVisConverter}
:
public class TrimmedTextBlockVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value == null) return Visibility.Collapsed;
FrameworkElement textBlock = (FrameworkElement)value;
textBlock.Measure(new System.Windows.Size(Double.PositiveInfinity, Double.PositiveInfinity));
if (((FrameworkElement)value).ActualWidth < ((FrameworkElement)value).DesiredSize.Width)
return Visibility.Visible;
else
return Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}