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:
Enabling the user sorting
this.radVirtualGrid1.AllowSorting = true;
Me.RadVirtualGrid1.AllowSorting = True
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.
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