GridControl.CustomColumnGroup Event

Allows you to create custom rules to group data.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v21.2.dll

Declaration

public event CustomColumnSortEventHandler CustomColumnGroup

Event Data

The CustomColumnGroup event's data class is CustomColumnSortEventArgs. The following properties provide information specific to this event:

Property Description
Column Gets the column whose values are being compared.
Handled Gets or sets whether a comparison operation is handled and no default processing is required.
ListSourceRowIndex1 Gets the index of the first of the two rows being compared in the data source.
ListSourceRowIndex2 Gets the index of the second of the two rows being compared in the data source.
Result Gets or sets the result of a custom comparison.
Row1
Row2
SortOrder Gets the sort order applied to the column.
Source Gets the grid control that raised the event.
Value1 Gets the first value being compared.
Value2 Gets the second value being compared.

Remarks

To create custom rules instead of the built-in grouping modes:

  1. Set the ColumnBase.SortMode property to Custom.
  2. Handle the CustomColumnGroup event.

To change the text displayed in group rows, handle the GridControl.CustomGroupDisplayText event.

Note

The CustomColumnGroup event does not work in Server Mode.

If you want to maintain a clean MVVM pattern and specify custom group operations in a View Model, create a command and bind it to the CustomColumnGroupCommand property.

Example

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.

DevExpress WPF | Grid Control - Custom Group Rules

View Example: How to Apply Custom Rules to Group Rows

<dxg:GridControl x:Name="grid" 
                 CustomColumnGroup="OnCustomColumnGroup" 
                 CustomGroupDisplayText="OnCustomGroupDisplayText">
    <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>
void OnCustomColumnGroup(object sender, CustomColumnSortEventArgs e) {
    if(e.Column.FieldName != "UnitPrice")
        return;
    double x = Math.Floor(Convert.ToDouble(e.Value1) / 10);
    double y = Math.Floor(Convert.ToDouble(e.Value2) / 10);
    e.Result = x > 9 && y > 9 ? 0 : x.CompareTo(y);
    e.Handled = true;
}

void OnCustomGroupDisplayText(object sender, CustomGroupDisplayTextEventArgs e) {
    if(e.Column.FieldName != "UnitPrice")
        return;
    string interval = IntervalByValue(e.Value);
    e.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;
}
See Also