Parameters
- item
- The item whose group name is to be retrieved.
- level
- A zero-based value representing the group level.
- culture
- The System.Globalization.CultureInfo to supply to the converter.
Return Value
An object representing the group name for the specified item.
All examples in this topic assume that the grid is bound to the Orders table of the Northwind database, unless stated otherwise.
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 example results in the group being present at initial loading; also, when removing and re-adding the group, the custom group description is not triggered. See below for an alternative approach to avoid this.
The implementation for the custom sort comparer assigned to the group description's SortComparer property is provided below.
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Xceed.Wpf.DataGrid
Imports System.Collections
Imports System.Globalization;
Namespace Xceed.Wpf.Documentation
Public Class AlphabeticalGroupDescription
Inherits DataGridGroupDescription
Public Sub New()
MyBase.New()
End Sub
Public Sub New(ByVal propertyName As String)
MyBase.New(propertyName)
End Sub
Public Overrides Function GroupNameFromItem(ByVal item As Object, _
ByVal level As Integer, _
ByVal culture As CultureInfo) As Object
Dim value As Object = MyBase.GroupNameFromItem(item, level, culture)
Try
Dim content As String = Convert.ToString(value)
value = content.ToUpper().Substring(0, 1)
Catch e1 As InvalidCastException
End Try
Return value
End Function
End Class
End Namespace
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.
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Collections
Namespace Xceed.Wpf.Documentation
Public Class ConsonantVowelComparer
Implements IComparer
Public Sub New()
End Sub
Public Function Compare(ByVal x As Object, _
ByVal y As Object) As Integer Implements IComparer.Compare
If (Typeof x Is String) AndAlso (Typeof y Is String) Then
Dim xString As String = x.ToString().ToLowerInvariant()
Dim yString As String = y.ToString().ToLowerInvariant()
Dim isXVowel As Boolean = m_vowels.Contains(xString)
Dim isYVowel As Boolean = m_vowels.Contains(yString)
If isXVowel Xor isYVowel Then
If isXVowel Then
Return -1
Else
Return 1
End If
End If
Return String.Compare(xString, yString)
End If
Throw New ArgumentException()
End Function
Private Const m_vowels As String = "aeiouy"
End Class
End Namespace
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 example results in the group being present at initial loading; also, when removing and re-adding the group, the custom group description is not triggered. See below for an alternative approach to avoid this.
The implementation for the custom sort comparer assigned to the group description's SortComparer property is provided below.
using System;
using System.Collections.Generic;
using System.Text;
using Xceed.Wpf.DataGrid;
using System.Collections;
namespace Xceed.Wpf.Documentation
{
public class AlphabeticalGroupDescription : DataGridGroupDescription
{
public AlphabeticalGroupDescription()
: base()
{
}
public AlphabeticalGroupDescription( string propertyName )
: base( propertyName )
{
}
public override object GroupNameFromItem( object item, int level,
System.Globalization.CultureInfo culture )
{
object value = base.GroupNameFromItem( item, level, culture );
try
{
string content = Convert.ToString( value );
value = content.ToUpper().Substring( 0, 1 );
}
catch( InvalidCastException )
{
}
return value;
}
}
}
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.
using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
namespace Xceed.Wpf.Documentation
{
public class ConsonantVowelComparer : IComparer
{
public ConsonantVowelComparer()
{
}
public int Compare( object x, object y )
{
if( ( x is string ) && ( y is string ) )
{
string xString = x.ToString().ToLowerInvariant();
string yString = y.ToString().ToLowerInvariant();
bool isXVowel = m_vowels.Contains( xString );
bool isYVowel = m_vowels.Contains( yString );
if( isXVowel ^ isYVowel )
return isXVowel ? -1 : 1;
return String.Compare( xString, yString );
}
throw new ArgumentException();
}
private const string m_vowels = "aeiouy";
}
}
The following code demonstrates how to use the custom group description by adding it to the DataGridCollectionViewSource's GroupDescriptions property.
<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>
The first example results in the group being present at initial loading; also, when removing and re-adding the group, the custom GroupDescription is not triggered. But by adding the custom GroupDescription directly to the Column, data is not grouped until the end-user drags the column to create the group, and this occurs each time the end-user performs the operation.
<Window.Resources>
<local:DateGroupDescription x:Key="myDateGroupDescription"
PropertyName="DateTimeFieldName" />
</Window.Resources>
[...]
<xcdg:DataGridControl.Columns>
<xcdg:Column FieldName="DateTimeFieldName"
GroupDescription="{StaticResource myDateGroupDescription}" />
</xcdg:DataGridControl.Columns>
Target Platforms: Windows 11, Windows 10, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
