Change layout of the columns in columnchooser

[Wesley]

Hi,
The text in the columnbuttons of the columnchooser of a radgridview is aligned in the middle (see sreenshot).
My customer wants the text aligned on the left.
How can I achieve this?

[Svett]

Hi Wesley,

You should create a custom cell element to alter the default behavior of the column chooser, when is shown by the context menu. You can use the following code snippet:

public class CustomGridHeaderCellElement : GridHeaderCellElement
{
    private static readonly MethodInfo MenuItemColumnChooserClickMethodInfo;

    static CustomGridHeaderCellElement()
        {
            MenuItemColumnChooserClickMethodInfo = typeof(GridHeaderCellElement).GetMethod("MenuItemColumnChooser_Click",
                BindingFlags.Instance | BindingFlags.NonPublic);
        }

    private EventHandler MenuItemColumnChooserClickEventHandler;

    public CustomGridHeaderCellElement(GridViewColumn column, GridRowElement row)
        : base(column, row)
        {
            MenuItemColumnChooserClickEventHandler = (EventHandler)Delegate.CreateDelegate(typeof(EventHandler), this, MenuItemColumnChooserClickMethodInfo);
        }

    protected override Type ThemeEffectiveType
        {
            get
            {
                return typeof(GridHeaderCellElement);
            }
        }

    protected override void CreateColumnChooserMenuItems(RadDropDownMenu contextMenu)
        {
            base.CreateColumnChooserMenuItems(contextMenu);

            RadMenuItem menu = this.GetMenuItem(contextMenu, RadGridLocalizationProvider.CurrentProvider.GetLocalizedString(RadGridStringId.ColumnChooserMenuItem));

            if (menu != null)
            {
                menu.Click -= MenuItemColumnChooserClickEventHandler;
                menu.Click += new EventHandler(menu_Click);
            }
        }

    private RadMenuItem GetMenuItem(RadDropDownMenu contextMenu, string text)
        {
            foreach (RadItem item in contextMenu.Items)
            {
                RadMenuItem menuItem = item as RadMenuItem;

                if (menuItem != null && menuItem.Text == text)
                {
                    return menuItem;
                }
            }

            return null;
        }

    private void menu_Click(object sender, EventArgs e)
        {
            StackLayoutElement elementHolder = this.GridViewElement.ColumnChooser.ColumnChooserControl.ColumnChooserElement.ElementsHolder;
            elementHolder.ChildrenChanged += this.OnChildrenChanged;
            MenuItemColumnChooserClickEventHandler(sender, e);
        }

    private void OnChildrenChanged(object sender, Telerik.WinControls.ChildrenChangedEventArgs e)
        {
            if (e.ChangeOperation == ItemsChangeOperation.Inserted)
            {
                LightVisualElement item = e.Child as LightVisualElement;
                item.TextAlignment = ContentAlignment.MiddleLeft;
            }
        }
}

Then you should use the CreateCell event to replace the default one:

private void radGridView1_CreateCell(object sender, GridViewCreateCellEventArgs e)
{
    if (e.CellType == typeof(GridHeaderCellElement))
    {
        e.CellType = typeof(CustomGridHeaderCellElement);
    }
}

I hope this helps.

Greetings,
Svett
the Telerik team

[Wesley]

Works like a sharm.
Thanks a lot.