In this walkthrough, you will learn how to integrate the DataCollection and DataConnector service components to use data virtualization with an OData service and bind the same to a data-aware control such as FlexGrid for WinForms. DataConnector is a cross-platform, data connectivity library for connecting to popular data sources such as OData and Dynamics 365.

Follow the steps below to apply Data Virtualization in FlexGrid for WinForms with OData:

Set up Application

1. Create a WinForms project.
2. Drag and drop the FlexGrid control from the toolbox onto the form.
3. Install the following NuGet packages:
   • C1.AdoNet.OData
   • C1.DataCollection.AdoNet
   • C1.DataCollection.BindingList
4. To add a NuGet package, right-click the ‘References’ node in the ‘Solution Explorer’ window and select ‘Manage NuGet Packages’.

Create Custom Class

1. Create a class 'Order' to provide data for binding to the FlexGrid control:
   • C#
   • Visual Basic

   • C#

   public class Order : INotifyPropertyChanged, IEditableObject
   {
       // Fields
       private int _orderId, _employeeId, _shipVia;
       private string _customerId, _shipName, _shipAddress, _shipCity,
           _shipRegion, _shipPostalCode, _shipCountry;
       private DateTimeOffset _orderDate, _requiredDate, _shippedDate;
       private decimal _freight;
      
   
       // Properties
   
       public int OrderID
       {
           get => _orderId;
           set
           {
               if (_orderId != value)
               {
                   _orderId = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string CustomerID
       {
           get => _customerId;
           set
           {
               if (_customerId != value)
               {
                   _customerId = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public int EmployeeID
       {
           get => _employeeId;
           set
           {
               if (_employeeId != value)
               {
                   _employeeId = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public DateTimeOffset OrderDate
       {
           get => _orderDate;
           set
           {
               if (_orderDate != value)
               {
                   _orderDate = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public DateTimeOffset RequiredDate
       {
           get => _requiredDate;
           set
           {
               if (_requiredDate != value)
               {
                   _requiredDate = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public DateTimeOffset ShippedDate
       {
           get => _shippedDate;
           set
           {
               if (_shippedDate != value)
               {
                   _shippedDate = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public int ShipVia
       {
           get => _shipVia;
           set
           {
               if (_shipVia != value)
               {
                   _shipVia = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public decimal Freight
       {
           get => _freight;
           set
           {
               if (_freight != value)
               {
                   _freight = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipName
       {
           get => _shipName;
           set
           {
               if (_shipName != value)
               {
                   _shipName = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipAddress
       {
           get => _shipAddress;
           set
           {
               if (_shipAddress != value)
               {
                   _shipAddress = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipCity
       {
           get => _shipCity;
           set
           {
               if (_shipCity != value)
               {
                   _shipCity = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipRegion
       {
           get => _shipRegion;
           set
           {
               if (_shipRegion != value)
               {
                   _shipRegion = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipPostalCode
       {
           get => _shipPostalCode;
           set
           {
               if (_shipPostalCode != value)
               {
                   _shipPostalCode = value;
                   OnPropertyChanged();
               }
           }
       }
   
       public string ShipCountry
       {
           get => _shipCountry;
           set
           {
               if (_shipCountry != value)
               {
                   _shipCountry = value;
                   OnPropertyChanged();
               }
           }
       }
   
       
   
       // INotifyPropertyChanged Members
   
       public event PropertyChangedEventHandler PropertyChanged;
   
       private void OnPropertyChanged([CallerMemberName] string propertyName = "")
       {
           OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
       }
   
       protected void OnPropertyChanged(PropertyChangedEventArgs e)
       {
           PropertyChanged?.Invoke(this, e);
   
       }
   
       // IEditableObject Members
   
       private Order _clone;
   
       public void BeginEdit()
       {
           _clone = (Order)MemberwiseClone();
       }
   
       public void CancelEdit()
       {
           if (_clone != null)
           {
               foreach (var p in GetType().GetRuntimeProperties())
               {
                   if (p.CanRead && p.CanWrite)
                   {
                       p.SetValue(this, p.GetValue(_clone, null), null);
                   }
               }
           }
       }
   
       public void EndEdit()
       {
           _clone = null;
       }
      
   }
   

   • Visual Basic

   Public Class Order
       Implements INotifyPropertyChanged, IEditableObject
   
   ' "Fields"
       Private _orderId, _employeeId, _shipVia As Integer
       Private _customerId, _shipName, _shipAddress, _shipCity, _shipRegion, _shipPostalCode, _shipCountry As String
       Private _orderDate, _requiredDate, _shippedDate As DateTimeOffset
       Private _freight As Decimal
   
   ' "Properties"
   
       Public Property OrderID As Integer
           Get
               Return _orderId
           End Get
           Set(ByVal value As Integer)
   
               If _orderId <> value Then
                   _orderId = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property CustomerID As String
           Get
               Return _customerId
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_customerId, value) Then
                   _customerId = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property EmployeeID As Integer
           Get
               Return _employeeId
           End Get
           Set(ByVal value As Integer)
   
               If _employeeId <> value Then
                   _employeeId = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property OrderDate As DateTimeOffset
           Get
               Return _orderDate
           End Get
           Set(ByVal value As DateTimeOffset)
   
               If _orderDate <> value Then
                   _orderDate = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property RequiredDate As DateTimeOffset
           Get
               Return _requiredDate
           End Get
           Set(ByVal value As DateTimeOffset)
   
               If _requiredDate <> value Then
                   _requiredDate = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShippedDate As DateTimeOffset
           Get
               Return _shippedDate
           End Get
           Set(ByVal value As DateTimeOffset)
   
               If _shippedDate <> value Then
                   _shippedDate = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipVia As Integer
           Get
               Return _shipVia
           End Get
           Set(ByVal value As Integer)
   
               If _shipVia <> value Then
                   _shipVia = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property Freight As Decimal
           Get
               Return _freight
           End Get
           Set(ByVal value As Decimal)
   
               If _freight <> value Then
                   _freight = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipName As String
           Get
               Return _shipName
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipName, value) Then
                   _shipName = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipAddress As String
           Get
               Return _shipAddress
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipAddress, value) Then
                   _shipAddress = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipCity As String
           Get
               Return _shipCity
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipCity, value) Then
                   _shipCity = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipRegion As String
           Get
               Return _shipRegion
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipRegion, value) Then
                   _shipRegion = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipPostalCode As String
           Get
               Return _shipPostalCode
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipPostalCode, value) Then
                   _shipPostalCode = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
       Public Property ShipCountry As String
           Get
               Return _shipCountry
           End Get
           Set(ByVal value As String)
   
               If Not Equals(_shipCountry, value) Then
                   _shipCountry = value
                   OnPropertyChanged()
               End If
           End Set
       End Property
   
   ' "INotifyPropertyChanged Members"
   
       Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
   
       Private Sub OnPropertyChanged(
   <CallerMemberName> ByVal Optional propertyName As String = "")
           OnPropertyChanged(New PropertyChangedEventArgs(propertyName))
       End Sub
   
       Protected Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
           RaiseEvent PropertyChanged(Me, e)
       End Sub
   
   ' IEditableObject Members
   
       Private _clone As Order
   
       Public Sub BeginEdit() Implements IEditableObject.BeginEdit
           _clone = CType(MemberwiseClone(), Order)
       End Sub
   
       Public Sub CancelEdit() Implements IEditableObject.CancelEdit
           If _clone IsNot Nothing Then
   
               For Each p In [GetType]().GetRuntimeProperties()
   
                   If p.CanRead AndAlso p.CanWrite Then
                       p.SetValue(Me, p.GetValue(_clone, Nothing), Nothing)
                   End If
               Next
           End If
       End Sub
   
       Public Sub EndEdit() Implements IEditableObject.EndEdit
           _clone = Nothing
       End Sub
   End Class
   

Bind FlexGrid to C1AdoNetVirtualDataCollection

1. In the Form_Load event, use Northwind OData Web APIs, and fetch the records from the Orders table. We use the generic class C1AdoNetVirtualDataCollection<T> to get strongly-typed records from the data source.You can use the non-generic class C1AdoNetVirtualDataCollection, which creates an appropriate type for the records at runtime. We wrap our virtual data collection object in C1DataCollectionBindingList to bind it to an instance of FlexGrid.Since the data collection is populated on a different thread, we use the BeginInvoke method of FlexGrid to avoid cross-thread exceptions for changing the DataSource. The PageSize property determines the number of rows requested in each fetch request. Note that in the FlexGrid control, the DrawModeEnum sets whether the control should fire after the OwnerDrawCell event.
   • C#
   • Visual Basic

   • C#

   private void Form1_Load(object sender, EventArgs e)
   {
       string connectionString = @"Url=https://services.odata.org/Experimental/Northwind/Northwind.svc/";
       var odataConnection = new C1ODataConnection(connectionString);
       var collectionView = new C1AdoNetVirtualDataCollection<Order>(odataConnection, "Orders");
       collectionView.PageSize = 100;
   
       c1FlexGrid1.BeginInvoke(new MethodInvoker(() =>
       {
           c1FlexGrid1.DataSource = new C1DataCollectionBindingList(collectionView);
           c1FlexGrid1.AllowFiltering = true;
           c1FlexGrid1.AllowSorting = C1.Win.C1FlexGrid.AllowSortingEnum.MultiColumn;
   
       }));
   
       c1FlexGrid1.DrawMode = C1.Win.C1FlexGrid.DrawModeEnum.OwnerDraw;
       c1FlexGrid1.OwnerDrawCell += c1FlexGrid1_OwnerDrawCell;
   }
   

   • Visual Basic

   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load, c1FlexGrid1.Click
       Dim connectionString As String = "Url=https://services.odata.org/Experimental/Northwind/Northwind.svc/"
       Dim odataConnection = New C1ODataConnection(connectionString)
       Dim collectionView = New C1AdoNetVirtualDataCollection(Of ODataVirtualizationDemo_VB.Order)(odataConnection, "Orders")
       collectionView.PageSize = 100
       Me.c1FlexGrid1.BeginInvoke(New MethodInvoker(Sub()
                                                        Me.c1FlexGrid1.DataSource = New C1DataCollectionBindingList(collectionView)
                                                        Me.c1FlexGrid1.AllowFiltering = True
                                                        Me.c1FlexGrid1.AllowSorting = C1.Win.C1FlexGrid.AllowSortingEnum.MultiColumn
                                                    End Sub))
       Me.c1FlexGrid1.DrawMode = C1.Win.C1FlexGrid.DrawModeEnum.OwnerDraw
       AddHandler Me.c1FlexGrid1.OwnerDrawCell, AddressOf Me.c1FlexGrid1_OwnerDrawCell
   End Sub
   

2. Double click the OwnerDrawCell event, and add the following code:
   • C#
   • Visual Basic

   • C#

   private void c1FlexGrid1_OwnerDrawCell(object sender, C1.Win.C1FlexGrid.OwnerDrawCellEventArgs e)
   {
       if (e.Row < c1FlexGrid1.Rows.Fixed)
           return;
   
       if (c1FlexGrid1.Cols[e.Col].DataType == typeof(DateTimeOffset))
       {
           object value = c1FlexGrid1[e.Row, e.Col];
           e.Text = (value != null) ? ((DateTimeOffset)value).DateTime.ToString("d") : string.Empty;
       }
   }
   

   • Visual Basic

   Private Sub c1FlexGrid1_OwnerDrawCell(sender As Object, e As C1.Win.C1FlexGrid.OwnerDrawCellEventArgs) Handles c1FlexGrid1.OwnerDrawCell
       If e.Row < Me.c1FlexGrid1.Rows.Fixed Then Return
   
       If Me.c1FlexGrid1.Cols(e.Col).DataType Is GetType(DateTimeOffset) Then
           Dim value As Object = Me.c1FlexGrid1(e.Row, e.Col)
           e.Text = If(value IsNot Nothing, CType(value, DateTimeOffset).DateTime.ToString("d"), String.Empty)
       End If
   End Sub
   

3. Run the project. Now, you can see that the grid initially has 100 rows (configured using the PageSize property). And, as we scroll down, more data is fetched automatically.