public class GroupFieldCollection :
    Collection<GroupField>,
    IList<GroupField>,
    ICollection<GroupField>,
    IList,
    ICollection,
    IReadOnlyList<GroupField>,
    IReadOnlyCollection<GroupField>,
    IEnumerable<GroupField>,
    IEnumerable

Public Class GroupFieldCollection
    Inherits Collection(Of GroupField)
    Implements IList(Of GroupField),
               ICollection(Of GroupField),
               IList,
               ICollection,
               IReadOnlyList(Of GroupField),
               IReadOnlyCollection(Of GroupField),
               IEnumerable(Of GroupField),
               IEnumerable

Methods of the GroupFieldCollection class allow a user to add new items to the collection and provide access to a particular GroupField object in the collection.

Examples

The report created in this example is bound to the CategoryProducts view of the sample Northwind database (the nwind.mdb file located in the directory, where you installed DevExpress demos).

This report contains two bands: DetailBand and GroupHeaderBand, and the Group Header band groups data by the "CategoryName" data field.

At runtime, data grouping can only be done prior to a report document is being created. To group data just before a report is printed/previewed, use the XRControl.BeforePrint event.

Please make sure to include all necessary assemblies to the References list of your project.

C#
VB.NET

using System;
using System.Windows.Forms;
using DevExpress.XtraReports.UI;
using DevExpress.DataAccess.ConnectionParameters;
using DevExpress.DataAccess.Sql;
using DevExpress.XtraReports.Configuration;
// ...

public XtraReport CreateDataGroupingReport() {
    // Create a report.
    XtraReport report = new XtraReport();

    // Create a data source with the required connection parameters.  
    Access97ConnectionParameters connectionParameters =
        new Access97ConnectionParameters("../../nwind.mdb", "", "");
    SqlDataSource ds = new SqlDataSource(connectionParameters);   
    CustomSqlQuery query = new CustomSqlQuery();
    query.Name = "customQuery";
    query.Sql = "SELECT * FROM CategoryProducts";
    ds.Queries.Add(query);
    ds.RebuildResultSchema();

    // Assign the data source to the report.
    report.DataSource = ds;
    report.DataMember = "customQuery";

    // Create a detail band and add it to the report.
    DetailBand detail = new DetailBand { HeightF = 40 };
    report.Bands.Add(detail);

    // Create a group header band and add it to the report.
    GroupHeaderBand ghBand = new GroupHeaderBand { HeightF = 40 };
    report.Bands.Add(ghBand);

    // Create a group field and assign it to the group header band.
    GroupField groupField = new GroupField("CategoryName");
    ghBand.GroupFields.Add(groupField);

    // Create new labels.
    XRLabel labelGroup = new XRLabel { ForeColor = System.Drawing.Color.Blue };
    XRLabel labelDetail = new XRLabel { LocationF = new System.Drawing.PointF(30, 0) };

    // Specify labels' bindings depending on the report's data binding mode.
    if (Settings.Default.UserDesignerOptions.DataBindingMode == DataBindingMode.Bindings) {
        labelGroup.DataBindings.Add("Text", null, "customQuery.CategoryName");
        labelDetail.DataBindings.Add("Text", null, "customQuery.ProductName");
    } else {
        labelGroup.ExpressionBindings.Add(new ExpressionBinding("BeforePrint", "Text", "[CategoryName]"));
        labelDetail.ExpressionBindings.Add(new ExpressionBinding("BeforePrint", "Text", "[ProductName]"));
    }
    // Add these labels to the report's bands.    
    ghBand.Controls.Add(labelGroup);          
    detail.Controls.Add(labelDetail);

    return report;
}

Imports System
Imports System.Windows.Forms
Imports DevExpress.XtraReports.UI
Imports DevExpress.DataAccess.ConnectionParameters
Imports DevExpress.DataAccess.Sql
Imports DevExpress.XtraReports.Configuration
' ...

Public Function CreateDataGroupingReport() As XtraReport
    ' Create a report.
    Dim report As XtraReport = New XtraReport()

    ' Create a data source with the required connection parameters.
    Dim connectionParameters As Access97ConnectionParameters = New Access97ConnectionParameters("../../nwind.mdb", "",
    Dim ds As SqlDataSource = New SqlDataSource(connectionParameters)
    Dim query As CustomSqlQuery = New CustomSqlQuery()
    query.Name = "customQuery"
    query.Sql = "SELECT * FROM CategoryProducts"
    ds.Queries.Add(query)
    ds.RebuildResultSchema()

    ' Assign the data source to the report.
    report.DataSource = ds
    report.DataMember = "customQuery"

    ' Create a detail band and add it to the report.
    Dim detail As DetailBand = New DetailBand With {.HeightF = 40}
    report.Bands.Add(detail)

    ' Create a group header band and add it to the report.
    Dim ghBand As GroupHeaderBand = New GroupHeaderBand With {.HeightF = 40}
    report.Bands.Add(ghBand)

    ' Create a group field and assign it to the group header band.
    Dim groupField As GroupField = New GroupField("CategoryName")
    ghBand.GroupFields.Add(groupField)

    ' Create new labels.
    Dim labelGroup As XRLabel = New XRLabel With {.ForeColor = System.Drawing.Color.Blue }
    Dim labelDetail As XRLabel = New XRLabel With {.LocationF = New System.Drawing.PointF(30, 0)}

    ' Specify label bindings depending on the report's data binding mode.
    If Settings.[Default].UserDesignerOptions.DataBindingMode = DataBindingMode.Bindings Then
        labelGroup.DataBindings.Add("Text", Nothing, "customQuery.CategoryName")
        labelDetail.DataBindings.Add("Text", Nothing, "customQuery.ProductName")
    Else
        labelGroup.ExpressionBindings.Add(New ExpressionBinding("BeforePrint", "Text", "[CategoryName]"))
        labelDetail.ExpressionBindings.Add(New ExpressionBinding("BeforePrint", "Text", "[ProductName]"))
    End If
    ' Add these labels to the report's bands.
    ghBand.Controls.Add(labelGroup)
    detail.Controls.Add(labelDetail)
    Return report
End Function

Object

Collection<GroupField>

GroupFieldCollection