Sorting Data

Glossary Item Box

Prerequisite Knowledge
Object Model Overview: DataGridCollectionView Class
DataGrid Fundamentals: Providing Data

Data items can be sorted by adding SortDescription objects to the SortDescriptions property of the DataGridCollectionViewSource or DataGridCollectionView to which a grid is bound, or directly through the Items property, and specifying the field name of the column by whose values to sort as well as the direction in which those values are to be sorted (see Example 1). 

A column's SortDirection property can be consulted to determine the direction in which its values are sorted, while the SortIndex property indicates the index of the column in the SortDescriptions collection.

To be notified when the SortDescriptions collection is changed, the CollectionChanged event of the collection's INotifyCollectionChanged interface implementation can be handled (see Example 4).

The name of the property in the data item and the value of the FieldName property must be identical in order for sorting to work.

Custom Sorting

In addition to the default type-based sorting, custom sorting can also be applied by providing an IComparer to the SortComparer property of one or more item properties defined in the DataGridCollectionView or DataGridCollectionViewSource to which a grid is bound (see Example 5). The comparer will be used whenever the values of the item property's corresponding column are sorted (e.g., clicking on the column header).

Sorting at Runtime

When a DataGridControl is created, by default, it contains a ColumnManagerRow in its fixed headers section that contains a ColumnManagerCell for each column in a grid. The content of one or more columns can be sorted by clicking in the corresponding ColumnManagerCell (see Figure 1).  

Clicking once will sort the column's values in an ascending direction, the second click will sort them in a descending direction, while the third click will remove any sorting that has been applied to the column's values. To sort the values of multiple columns, hold the SHIFT key while clicking on a ColumnManagerCell.

Any GroupByItems contained in a GroupByControl can also be used to sort the content of the columns which they represent (see Figure 2).  


Figure 1: ColumnManagerCell

Figure 2: GroupByItem

The AllowSort property, which can be set on a column-manager row or group-by control, indicates whether the end user can sort columns. To prevent columns from being reordered (i.e., change their visible positions) when column-manager cells are dragged to another location, a column-manager row's AllowColumnReorder property can be set to false (see Example 2).

These properties only affect end-user interaction and do not prevent columns from being sorted or reordered programmatically.

Examples

All examples in this topic assume that the grid is bound to the Orders table of the Northwind database, unless stated otherwise.

ShowExample 1: Sorting data items

The following example demonstrates how to sort the data items in an ascending direction according to the values of the ShipCountry column.

XAML Copy Code
<Grid xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase"
      xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
  <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                     Source="{Binding Source={x:Static Application.Current},
                                                       Path=Orders}">
     <xcdg:DataGridCollectionViewSource.SortDescriptions>
       <scm:SortDescription PropertyName="ShipCountry" Direction="Ascending"/>
     </xcdg:DataGridCollectionViewSource.SortDescriptions>
    </xcdg:DataGridCollectionViewSource>          
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}">
    <xcdg:DataGridControl.Columns>
      <xcdg:Column FieldName="ShipCountry" VisiblePosition="0"/>
    </xcdg:DataGridControl.Columns>
  </xcdg:DataGridControl>
</Grid>
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

ShowExample 2: Preventing sorting and grouping

The following example demonstrates how to bind a grid to the Orders table and prevent columns from being sorted and reordered and groups from being created or removed. By default, the ShipCountry and ShipCity columns will be sorted, grouped, and fixed.

XAML Copy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
      xmlns:d="clr-namespace:System.Windows.Data;assembly=PresentationFramework"
      xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase">
  <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                    Source="{Binding Source={x:Static Application.Current},
                                                      Path=Orders}">
      <xcdg:DataGridCollectionViewSource.SortDescriptions>
        <scm:SortDescription PropertyName="ShipCountry" Direction="Ascending"/>
        <scm:SortDescription PropertyName="ShipCity" Direction="Ascending"/>
      </xcdg:DataGridCollectionViewSource.SortDescriptions>
      <xcdg:DataGridCollectionViewSource.GroupDescriptions>
        <xcdg:DataGridGroupDescription PropertyName="ShipCountry"/>
        <xcdg:DataGridGroupDescription PropertyName="ShipCity"/>
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
    </xcdg:DataGridCollectionViewSource>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}">      
    <xcdg:DataGridControl.Columns>
      <xcdg:Column FieldName="ShipCountry" VisiblePosition="0"/>
      <xcdg:Column FieldName="ShipCity" VisiblePosition="1"/>
    </xcdg:DataGridControl.Columns>
    <xcdg:DataGridControl.View>
      <xcdg:TableView FixedColumnCount="2" UseDefaultHeadersFooters="False">
        <xcdg:TableView.FixedHeaders>
          <DataTemplate>
            <xcdg:GroupByControl AllowSort="False" AllowGroupingModification="False"/>
          </DataTemplate>
          <DataTemplate>
            <xcdg:ColumnManagerRow AllowSort="False" AllowColumnReorder="False"/>
          </DataTemplate>
        </xcdg:TableView.FixedHeaders>
      </xcdg:TableView>
    </xcdg:DataGridControl.View>
  </xcdg:DataGridControl>
</Grid>

ShowExample 3: Custom group sorting

This example demonstrates how to create a custom group description by deriving from the DataGridGroupDescription class and overriding the GroupNameFromItem method. The custom group description will group items according to the first letter in the value received as a parameter.

The implementation for the custom sort comparer assigned to the group description's SortComparer property is provided below.

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MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

The following code demonstrates how to use the custom group description by adding it to the DataGridCollectionViewSource's GroupDescriptions property.

XAML Copy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
     xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
  <Grid.Resources>      
    <local:ConsonantVowelComparer x:Key="consonantVowelComparer"/>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                       Source="{Binding
                                                Source={x:Static Application.Current},
                                                Path=Orders}">
     <xcdg:DataGridCollectionViewSource.GroupDescriptions>
       <local:AlphabeticalGroupDescription PropertyName="ShipCountry"
                                SortComparer="{StaticResource consonantVowelComparer}"/>
     </xcdg:DataGridCollectionViewSource.GroupDescriptions>
    </xcdg:DataGridCollectionViewSource>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
</Grid>
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

The following code provides the implementation for the custom sort comparer that is used to sort, by vowels then consonants, the group descriptions create above.

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MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

ShowExample 4: Handling collection-changed events

The following example demonstrates how to subscribe to the CollectionChanged event of the DataGridCollectionView.SortDescriptions collection's INotifyCollectionChanged interface implementation to be notified when sorting applied to a grid's columns changes.

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MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

ShowExample 5: Providing a custom sort comparer

The following example demonstrates how to provide a custom sort comparer that sorts addresses. The AddressComparer class (provided below) will first sort addresses which begin with numeric values by street name and then civic number. Address that do not have a civic number will be sorted alphabetically.

XAML Copy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
      xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
   <Grid.Resources>
      <local:AddressComparer x:Key="addressComparer"/>
      <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                         Source="{Binding Source={x:Static Application.Current},
                                                          Path=Orders}"
                                         AutoCreateItemProperties="False">
         <xcdg:DataGridCollectionViewSource.ItemProperties>
            <xcdg:DataGridItemProperty Name="ShipCountry" />
            <xcdg:DataGridItemProperty Name="ShipCity" />
            <xcdg:DataGridItemProperty Name="ShipAddress"
                                       SortComparer="{StaticResource addressComparer}"/>
            <xcdg:DataGridItemProperty Name="ShipVia" />
         </xcdg:DataGridCollectionViewSource.ItemProperties>
      </xcdg:DataGridCollectionViewSource>
   </Grid.Resources>
   <xcdg:DataGridControl x:Name="OrdersGrid"
                         ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>         
</Grid>
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.
MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

The following code provides the implementation of the AddressComparer class.

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MISSING WIDGET TYPE: The "Fallback" Widget Type could not be found. The "Fallback" Widget Type may have been deleted since this Widget was created.

 

 

See Also

DataGrid Fundamentals
{Providing Data}