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Sorting Overview

RadVirtualGrid supports data sorting. Set the RadVirtualGrid.AllowSorting property to true in order to enable the user sorting feature. To enable the multiple columns sorting, you should set the RadVirtualGrid.AllowMultiColumnSorting property to true:

virtualgrid-sorting 001

Enabling the user sorting

this.radVirtualGrid1.AllowSorting = true;

Me.RadVirtualGrid1.AllowSorting = True

virtualgrid-sorting 002

Enabling multiple columns sorting

this.radVirtualGrid1.AllowMultiColumnSorting = true;

Me.RadVirtualGrid1.AllowMultiColumnSorting = True

It is necessary to handle the SortChanged event which is fired once the SortDescriptors collection is changed. In the event handler you should extract the sorted data from the external data source.

note

Please refer to the Populating with data help article which demonstrates how to extract the necessary data and fill the virtual grid with data.

The following example demonstrates how to achieve sorting functionality in RadVirtualGrid filled with Northwind.Customers table:


private void radVirtualGrid1_SortChanged(object sender, VirtualGridEventArgs e)
{
    SelectData();
}

private readonly string selectCommand = "SELECT CustomerID, CompanyName, ContactName, ContactTitle, Address, PostalCode FROM Customers";
private string[] columnNames = new string[] { "CompanyName", "ContactName", "ContactTitle", "Address", "PostalCode" };
List<Customer> data = new List<Customer>();

private void SelectData()
{
    string sortExpression = this.radVirtualGrid1.SortDescriptors.Expression;
    if (!string.IsNullOrEmpty(sortExpression))
    {
        sortExpression = "ORDER BY " + sortExpression;
    }

    string commandString = String.Format("{0} {1}", selectCommand, sortExpression);
    using (System.Data.OleDb.OleDbCommand command = new System.Data.OleDb.OleDbCommand(commandString))
    {
        command.Connection = new System.Data.OleDb.OleDbConnection(Settings.Default.NwindConnectionString);
        command.Connection.Open();
        IDataReader reader = command.ExecuteReader();
        data.Clear();

        while (reader.Read())
        {
            Customer customer = new Customer(
                Convert.ToString(reader[0]),
                Convert.ToString(reader[1]),
                Convert.ToString(reader[2]),
                Convert.ToString(reader[3]),
                Convert.ToString(reader[4]),
                Convert.ToString(reader[5]));
            data.Add(customer);
        }

        command.Connection.Close();
    }

    this.radVirtualGrid1.RowCount = data.Count;
}

private void radVirtualGrid1_CellValueNeeded(object sender, Telerik.WinControls.UI.VirtualGridCellValueNeededEventArgs e)
{
    if (e.ColumnIndex < 0)
        return;
    if (e.RowIndex == RadVirtualGrid.HeaderRowIndex)
    {
        e.Value = columnNames[e.ColumnIndex];
    }

    if (e.RowIndex < 0)
    {
        e.FieldName = columnNames[e.ColumnIndex];
    }

    if (e.RowIndex >= 0 && e.RowIndex < data.Count)
    {
        e.Value = data[e.RowIndex][e.ColumnIndex];
    }
}

private void VirtualGridSorting_Load(object sender, EventArgs e)
{            
    this.radVirtualGrid1.ColumnCount = columnNames.Length;
    this.radVirtualGrid1.CellValueNeeded += radVirtualGrid1_CellValueNeeded;
    SelectData();
}

public class Customer
{
    public string CustomerId { get; set; }

    public string CompanyName { get; set; }

    public string ContactName { get; set; }

    public string ContactTitle { get; set; }

    public string Address { get; set; }

    public string PostalCode { get; set; }

    public Customer(string customerId, string companyName, string contactName, string contactTitle, string address, string postalCode)
    {
        this.CustomerId = customerId;
        this.CompanyName = companyName;
        this.ContactName = contactName;
        this.ContactTitle = contactTitle;
        this.Address = address;
        this.PostalCode = postalCode;
    }

    public string this[int i]
    {
        get
        {
            switch (i)
            {
                case 0:
                    return CompanyName;
                case 1:
                    return ContactName;
                case 2:
                    return ContactTitle;
                case 3:
                    return Address;
                case 4:
                    return PostalCode;
                default:
                    return String.Empty;
            }
        }
    }
}

Private Sub radVirtualGrid1_SortChanged(sender As Object, e As VirtualGridEventArgs)
    SelectData()
End Sub
Private ReadOnly selectCommand As String = "SELECT CustomerID, CompanyName, ContactName, ContactTitle, Address, PostalCode FROM Customers"
Private columnNames As String() = New String() {"CompanyName", "ContactName", "ContactTitle", "Address", "PostalCode"}
Private data As New List(Of Customer)()
Private Sub SelectData()
    Dim sortExpression As String = Me.RadVirtualGrid1.SortDescriptors.Expression
    If Not String.IsNullOrEmpty(sortExpression) Then
        sortExpression = Convert.ToString("ORDER BY ") & sortExpression
    End If
    Dim commandString As String = [String].Format("{0} {1}", selectCommand, sortExpression)
    Using command As New System.Data.OleDb.OleDbCommand(commandString)
        command.Connection = New System.Data.OleDb.OleDbConnection(My.Settings.NwindConnectionString)
        command.Connection.Open()
        Dim reader As IDataReader = command.ExecuteReader()
        data.Clear()
        While reader.Read()
            Dim customer As New Customer(Convert.ToString(reader(0)), Convert.ToString(reader(1)), Convert.ToString(reader(2)), _
                                         Convert.ToString(reader(3)), Convert.ToString(reader(4)), Convert.ToString(reader(5)))
            data.Add(customer)
        End While
        command.Connection.Close()
    End Using
    Me.RadVirtualGrid1.RowCount = data.Count
End Sub
Private Sub radVirtualGrid1_CellValueNeeded(sender As Object, e As Telerik.WinControls.UI.VirtualGridCellValueNeededEventArgs)
    If e.ColumnIndex < 0 Then
        Return
    End If
    If e.RowIndex = RadVirtualGrid.HeaderRowIndex Then
        e.Value = columnNames(e.ColumnIndex)
    End If
    If e.RowIndex < 0 Then
        e.FieldName = columnNames(e.ColumnIndex)
    End If
    If e.RowIndex >= 0 AndAlso e.RowIndex < data.Count Then
        e.Value = data(e.RowIndex)(e.ColumnIndex)
    End If
End Sub
Private Sub VirtualGridSorting_Load(sender As Object, e As EventArgs) Handles Me.Load
    Me.RadVirtualGrid1.ColumnCount = columnNames.Length
    AddHandler Me.RadVirtualGrid1.CellValueNeeded, AddressOf radVirtualGrid1_CellValueNeeded
    SelectData()
End Sub
Public Class Customer
    Public Property CustomerId() As String
        Get
            Return m_CustomerId
        End Get
        Set(value As String)
            m_CustomerId = value
        End Set
    End Property
    Private m_CustomerId As String
    Public Property CompanyName() As String
        Get
            Return m_CompanyName
        End Get
        Set(value As String)
            m_CompanyName = value
        End Set
    End Property
    Private m_CompanyName As String
    Public Property ContactName() As String
        Get
            Return m_ContactName
        End Get
        Set(value As String)
            m_ContactName = value
        End Set
    End Property
    Private m_ContactName As String
    Public Property ContactTitle() As String
        Get
            Return m_ContactTitle
        End Get
        Set(value As String)
            m_ContactTitle = value
        End Set
    End Property
    Private m_ContactTitle As String
    Public Property Address() As String
        Get
            Return m_Address
        End Get
        Set(value As String)
            m_Address = value
        End Set
    End Property
    Private m_Address As String
    Public Property PostalCode() As String
        Get
            Return m_PostalCode
        End Get
        Set(value As String)
            m_PostalCode = value
        End Set
    End Property
    Private m_PostalCode As String
    Public Sub New(customerId As String, companyName As String, contactName As String, contactTitle As String, address As String, postalCode As String)
        Me.CustomerId = customerId
        Me.CompanyName = companyName
        Me.ContactName = contactName
        Me.ContactTitle = contactTitle
        Me.Address = address
        Me.PostalCode = postalCode
    End Sub
    Default Public ReadOnly Property Item(i As Integer) As String
        Get
            Select Case i
                Case 0
                    Return CompanyName
                Case 1
                    Return ContactName
                Case 2
                    Return ContactTitle
                Case 3
                    Return Address
                Case 4
                    Return PostalCode
                Case Else
                    Return [String].Empty
            End Select
        End Get
    End Property
End Class

See Also

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