WPF DataGrid Save Column Width

Question

I want to Save and Restore DataGrid columns width, I tried this:

private void dataGrid_LayoutUpdated(object sender, EventArgs e)
{
    foreach (var item in dataGrid.Columns.GetEnumeratorWithIndex())
    {
        Settings.ColumnWidth[item.Index] =
            new DataGridLength(item.Value.Width.Value,
            DataGridLengthUnitType.Pixel,
            item.Value.Width.DesiredValue, item.Value.Width.DisplayValue);
    }
}

Restore:

foreach (var item in dataGrid.Columns.GetEnumeratorWithIndex())
{
    item.Value.Width = new
        DataGridLength(Settings.ColumnWidth[item.Index].Value,
        DataGridLengthUnitType.Pixel,
        Settings.ColumnWidth[item.Index].DesiredValue,
        Settings.ColumnWidth[item.Index].DisplayValue);
}

But not working and all columns stored as Auto.

Update:

Answer 1

Try using the property ActualWidth:

for (int index = 0; index < dataGrid.Columns.Count; index++)
    Settings.ColumnWidth[index] = new
        DataGridLength(dataGrid.Columns[index].ActualWidth);

Example of reading column sizes:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
    private void GetWidthsClick(object sender, RoutedEventArgs e)
    {
        MessageBox.Show(string.Join("; ",
            dataGrid.Columns.Select(column => column.Width))
            + Environment.NewLine + string.Join("; ",
            dataGrid.Columns.Select(column => column.ActualWidth)));
    }
}
public class TextsViewModel
{
    public ObservableCollection<Texts> Rows { get; } =
        new ObservableCollection<Texts>()
    {
        new Texts() {Text1="123", Text2="45678",
            Text3="90qwer", Text4="tyuiio", Text5="as"},
        new Texts() {Text1="asad", Text2="gfg",
            Text3="hkjhk", Text4="kl", Text5="fgfhgf"}
    };
}
public class Texts
{
    public string Text1 { get; set; }
    public string Text2 { get; set; }
    public string Text3 { get; set; }
    public string Text4 { get; set; }
    public string Text5 { get; set; }
}

XAML:

<Grid DataContext="{DynamicResource viewModel}">
    <FrameworkElement.Resources>
        <local:TextsViewModel x:Key="viewModel"/>
    </FrameworkElement.Resources>
    <Grid.RowDefinitions>
        <RowDefinition/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <DataGrid x:Name="dataGrid" ItemsSource="{Binding Rows}"
        HorizontalAlignment="Center"/>
    <Button Content="Get Widths" Grid.Row="1"
            Click="GetWidthsClick"
            Margin="5" Padding="15 5"/>
</Grid>