DataView

The IDataView interface provides access to the view generated from the data displayed in the DataGrid instance.

The items in the IDataView can differ from the ones in the ItemsSource when a data operation, such as grouping, sorting, or filtering, is applied.

Before using the IDataView, check the IDataView.IsDataReady property or use the DataBindingComplete event or command.

The actual implementation of the IDataView is stateless and each RadDataGrid.GetDataView method call will return a new object instance.

Properties

• IsDataReady—Determines whether all the internal data operations are completed and the view can be properly accessed.
• Items—Gets the top-level items within the view. The items can be either IDataGroup instances, or business objects if no grouping is applied.

Methods

• GetAggregateValue(int aggregateIndex, IDataGroup group)—Gets the computed aggregate value associated with the provided aggregate index.

  • aggregateIndex—The zero-based index of the AggregateDescriptorBase within the RadDataGrid.AggregateDescriptors collection.
  • group—The IDataGroup instance to get the value for. Pass null to retrieve the computed grand total value.

• GetAggregateValues(string propertyName, IDataGroup group)—Gets the computed aggregate values for all the PropertyAggregateDescriptor instances associated with the provided property name.

  • propertyName—The name of the property to filter aggregates by.
  • group—The IDataGroup instance to get the value for. Pass null to retrieve the computed grand total value.

• GetGroups(Predicate<IDataGroup> condition = null)—Enumerates all the present IDataGroup instances by using depth-first approach. You can use an optional condition to filter the results.

• GetIsExpanded(IDataGroup group)—Determines whether the provided group is considered "expanded", that is, to have its ChildItems available within the UI.

• GetParentGroup(object item)—Gets the IDataGroup instance where the specified item resides. This method will return null, if no grouping is applied or the item does not belong to the ItemsSource of the grid.

• ExpandGroup(IDataGroup group)—Attempts to expand the provided IDataGroup instance.

  Use the ExpandGroup Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.ExpandGroup(currentView.Items[0] as IDataGroup); 
      } 
  

• CollapseGroup(IDataGroup group)—Attempts to collapse the provided IDataGroup instance.

  Use the CollapseGroup Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.CollapseGroup(currentView.Items[0] as IDataGroup); 
      } 
  

• ExpandAll()—Expands all the groups.

  Use the ExpandAll Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.ExpandAll(); 
      } 
  

• CollapseAll()—Collapses all the groups.

  Use the CollapseAll Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.CollapseAll(); 
      } 
  

• ExpandItem(object item)—Expands the chain of groups where the specified item resides.

  Use the ExpandItem Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.ExpandItem(this.dataGrid.SelectedItem); 
      } 
  

• CollapseItem(object item)—Collapses the immediate groups that contain the specified item.

  Use the CollapseItem Method

      var currentView = this.dataGrid.GetDataView(); 
   
      if (currentView.IsDataReady) 
      { 
          currentView.CollapseItem(this.dataGrid.SelectedItem); 
      } 
  

  Using the DataBindingComplete Command

The following examples respectively demonstrate how to create a command that collapses all groups except the first one each time when the DataGrid is grouped, and to add the custom command to the Commands of the DataGrid.

Custom DataBindingComplete Command

public class DataBindingComplete : DataGridCommand 
{ 
    public override bool CanExecute(object parameter) 
    { 
        if ((parameter as DataBindingCompleteEventArgs).ChangeFlags.HasFlag(DataChangeFlags.Group)) 
        { 
            return true; 
        } 
        else 
        { 
            return false; 
        } 
    } 
 
    public override void Execute(object parameter) 
    { 
        this.Owner.GetDataView().CollapseAll(); 
 
        if (this.Owner.GroupDescriptors.Count > 0) 
        { 
            this.Owner.GetDataView().ExpandGroup((this.Owner.GetDataView().Items[0] as IDataGroup)); 
        } 
 
        base.Execute(parameter); 
    } 
} 

Add the Custom Command to the Commands Collection

<Grid xmlns:telerikGrid="using:Telerik.UI.Xaml.Controls.Grid"> 
    <telerikGrid:RadDataGrid > 
        <telerikGrid:RadDataGrid.Commands> 
            <local:DataBindingComplete Id="DataBindingComplete" /> 
        </telerikGrid:RadDataGrid.Commands> 
    </telerikGrid:RadDataGrid> 
</Grid> 

See Also

• Commands
• Aggregates