wpf-devexpress-dot-xpf-dot-grid-dot-gridcontrol-b6dcf479.md
Gets or sets a command that applies custom rules to group rows.
Namespace : DevExpress.Xpf.Grid
Assembly : DevExpress.Xpf.Grid.v25.2.dll
NuGet Package : DevExpress.Wpf.Grid.Core
public ICommand<RowSortArgs> CustomColumnGroupCommand { get; set; }
Public Property CustomColumnGroupCommand As ICommand(Of RowSortArgs)
| Type | Description |
|---|---|
| ICommand<RowSortArgs> |
A command that applies custom rules to group rows.
|
Bind a command to the CustomColumnGroupCommand property to maintain a clean MVVM pattern. The command works like a CustomColumnGroup event handler and allows you to specify custom group operations in a View Model.
To create custom rules instead of the built-in group modes:
Use the GridControl.CustomGroupDisplayTextCommand property to change the text displayed in group rows.
Note
The CustomColumnGroupCommand property does not work in Server Mode.
The following example shows how to apply custom rules to group rows. When you group data by the Unit Price column, rows in this column that have values between 0 and 10 are combined into a single group. Rows whose values fall between 10 and 20 are combined into another group, and so forth.
View Example: How to Apply Custom Rules to Group Rows
<dxg:GridControl ItemsSource="{Binding ListPerson}"
CustomColumnGroupCommand="{Binding CustomColumnGroupCommand}"
CustomGroupDisplayTextCommand="{Binding CustomGroupDisplayTextCommand}">
<dxg:GridControl.Columns>
<dxg:GridColumn FieldName="FirstName" />
<dxg:GridColumn FieldName="LastName" />
<dxg:GridColumn FieldName="UnitPrice" SortMode="Custom" GroupIndex="0">
<dxg:GridColumn.EditSettings>
<dxe:SpinEditSettings DisplayFormat="c2" />
</dxg:GridColumn.EditSettings>
</dxg:GridColumn>
</dxg:GridControl.Columns>
<dxg:GridControl.View>
<dxg:TableView AutoWidth="True" ShowGroupedColumns="True"/>
</dxg:GridControl.View>
</dxg:GridControl>
using DevExpress.Mvvm;
using DevExpress.Mvvm.DataAnnotations;
using DevExpress.Mvvm.Xpf;
// ...
public class MainViewModel : ViewModelBase {
// ...
[Command]
public void CustomColumnGroup(RowSortArgs args) {
if(args.FieldName != "UnitPrice")
return;
double x = Math.Floor(Convert.ToDouble(args.FirstValue) / 10);
double y = Math.Floor(Convert.ToDouble(args.SecondValue) / 10);
args.Result = x > 9 && y > 9 ? 0 : x.CompareTo(y);
}
[Command]
public void CustomGroupDisplayText(GroupDisplayTextArgs args) {
if(args.FieldName != "UnitPrice")
return;
string interval = IntervalByValue(args.Value);
args.DisplayText = interval;
}
// Gets the interval which contains the specified value.
private string IntervalByValue(object val) {
double d = Math.Floor(Convert.ToDouble(val) / 10);
string ret = string.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10);
if(d > 9)
ret = string.Format(">= {0:c} ", 100);
return ret;
}
}
Imports DevExpress.Mvvm
Imports DevExpress.Mvvm.DataAnnotations
Imports DevExpress.Mvvm.Xpf
' ...
Public Class MainViewModel
Inherits ViewModelBase
' ...
<Command>
Public Sub CustomColumnGroup(ByVal args As RowSortArgs)
If Not Equals(args.FieldName, "UnitPrice") Then Return
Dim x As Double = Math.Floor(Convert.ToDouble(args.FirstValue) / 10)
Dim y As Double = Math.Floor(Convert.ToDouble(args.SecondValue) / 10)
args.Result = If(x > 9 AndAlso y > 9, 0, x.CompareTo(y))
End Sub
<Command>
Public Sub CustomGroupDisplayText(ByVal args As GroupDisplayTextArgs)
If Not Equals(args.FieldName, "UnitPrice") Then Return
Dim interval As String = IntervalByValue(args.Value)
args.DisplayText = interval
End Sub
' Gets the interval which contains the specified value.
Private Function IntervalByValue(ByVal val As Object) As String
Dim d As Double = Math.Floor(Convert.ToDouble(val) / 10)
Dim ret As String = String.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10)
If d > 9 Then ret = String.Format(">= {0:c} ", 100)
Return ret
End Function
End Class
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CustomColumnGroupCommand property.
Note
The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.
wpf-data-grid-implement-custom-grouping/CS/CustomGrouping_MVVM/MainWindow.xaml#L13
<dxg:GridControl ItemsSource="{Binding ListPerson}"
CustomColumnGroupCommand="{Binding CustomColumnGroupCommand}"
CustomGroupDisplayTextCommand="{Binding CustomGroupDisplayTextCommand}">
See Also