LeftPanelPartial.cshtml

<h3 class="leftpanel-section section-caption">Categories</h3>
@Html.DevExpress().NavBar(navBarSettings => {
    navBarSettings.SyncSelectionMode = SyncSelectionMode.CurrentPathAndQuery;
    navBarSettings.Name = "categoriesNavBar";
    navBarSettings.AllowSelectItem = true;
    navBarSettings.ShowGroupHeaders = false;
    navBarSettings.Width = Unit.Percentage(100);
    navBarSettings.ControlStyle.CssClass = "filters-navbar";
    navBarSettings.Styles.Item.CssClass = "item";
    navBarSettings.Groups.Add(group => {
        group.Items.Add(item => {
            item.Name = "Category1";
            item.Text = "Category1";
            item.NavigateUrl = "FormLayout";
        });
        group.Items.Add(item => {
            item.Name = "Category2";
            item.Text = "Category2";
            item.NavigateUrl = "FormLayout?2";
        });
        group.Items.Add(item => {
            item.Name = "Category3";
            item.Text = "Category3";
            item.NavigateUrl = "FormLayout?3";
        });
    });
}).GetHtml()