IComboBoxSettings.ListRenderMode Property

Specifies whether virtual scrolling is enabled in the combo box editor.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v23.2.dll

NuGet Package: DevExpress.Blazor

Declaration

[DefaultValue(ListRenderMode.Entire)]
[Parameter]
ListRenderMode ListRenderMode { get; set; }

Property Value

Type	Default	Description
ListRenderMode	Entire	An enumeration value.

Available values:

Name	Description
Entire	The editor renders the entire item list. Use this option for small item lists where scrolling should be instant.
Virtual	The editor renders list items only after they appear in the viewport. This approach improves performance when the list contains many items.

Remarks

In virtual scrolling mode, the combo box editor renders items in the drop-down list only after they appear in the viewport. Enable this mode when the combo box contains a large number of items to improve editor performance.

Note

When the combo box editor is in virtual scrolling mode, drop-down list width can change while the user scrolls the list up or down.

Use the ListRenderMode property to enable or disable the virtual scrolling mode in the combo box at runtime. In markup, use the DxComboBoxSettings.ListRenderMode property to enable virtual scrolling.

The IComboBoxSettings interface allows you to get and customize settings of a combo box editor at runtime. You can get editor settings in the following ways:

• Call the GetColumnEditSettings method to get editor settings of the column bound to the specified data source field.

  Important

  You need to enclose your code between BeginUpdate and EndUpdate method calls to change values of Grid component parameters outside the Grid component markup. Otherwise, an exception occurs.

  var comboBoxSettings = e.Grid.GetColumnEditSettings<IComboBoxSettings>("Employee");
  if(comboBoxSettings != null) {
      e.Grid.BeginUpdate();
      comboBoxSettings.ListRenderMode = ListRenderMode.Virtual;
      e.Grid.EndUpdate();
  }
  

• Handle the CustomizeFilterRowEditor event to customize a cell editor in the filter row.

  void Grid_CustomizeFilterRowEditor(GridCustomizeFilterRowEditorEventArgs e) {
      if(e.EditSettings is IComboBoxSettings comboBoxSettings)
          comboBoxSettings.ListRenderMode = ListRenderMode.Virtual;
  }
  

• Handle the CustomizeDataRowEditor event to customize a cell editor in a data row.

  void Grid_CustomizeDataRowEditor(GridCustomizeDataRowEditorEventArgs e) {
      if(e.EditSettings is IComboBoxSettings comboBoxSettings)
          comboBoxSettings.ListRenderMode = ListRenderMode.Virtual;
  }