Combining RadDragDropService and OLE Drag and Drop
This article demonstrates a sample approach how to achieve drag and drop functionality between RadScheduler and RadListControl. For this purpose, we will use a combination between the RadDragDropService, supported by the RadScheduler control, and the OLE drag-and-drop, which is supported by all controls from the Telerik UI for WinForms suite.
Let’s assume that our RadScheduler is in bound mode and the RadListControl is populated manually with items. Set the AllowDrop property to true for both of the controls.
Drag and Drop from RadScheduler to RadListControl Using RadDragDropService
To implement drag and drop functionality for this scenario, we will use the SchedulerElement.DragDropBehavior, which is a derivative of the RadDragDropService. Subscribe to its PreviewDragOver and PreviewDragDrop events. In the PreviewDragOver event allow dropping over a RadListElement. The PreviewDragDrop event performs the actual inserting of the dragged appointment into the RadListControl.Items collection:
Behavior PreviewDragOver
private void DragDropBehavior_PreviewDragOver(object sender, Telerik.WinControls.RadDragOverEventArgs e)
{
e.CanDrop = e.HitTarget is RadListElement;
}
private void DragDropBehavior_PreviewDragDrop(object sender, Telerik.WinControls.RadDropEventArgs e)
{
DragFeedbackElement draggedInstance = e.DragInstance as DragFeedbackElement;
if (draggedInstance == null)
{
return;
}
RadListElement listElement = e.HitTarget as RadListElement;
if (listElement == null)
{
return;
}
e.Handled = true;
RadListControl listControl = listElement.ElementTree.Control as RadListControl;
RadListVisualItem targetItem = listControl.ElementTree.GetElementAtPoint(e.DropLocation) as RadListVisualItem;
int indexToInsert;
if (targetItem != null)
{
indexToInsert = targetItem.Data.RowIndex;
}
else
{
indexToInsert = listControl.Items.Count;
}
Appointment draggedAppointment = draggedInstance.AssociatedAppointment as Appointment;
SchedulerUIHelper.DeleteAppointment(draggedAppointment, this.radScheduler1);
RadListDataItem newItem = new RadListDataItem(draggedAppointment.Summary);
listControl.Items.Insert(indexToInsert, newItem);
//save changes to data base
SaveChanges();
}
public void SaveChanges()
{
appointmentsResourcesTableAdapter.Adapter.AcceptChangesDuringUpdate = false;
SchedulerDataDataSet.AppointmentsResourcesDataTable deletedChildRecords =
this.schedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Deleted)
as SchedulerDataDataSet.AppointmentsResourcesDataTable;
SchedulerDataDataSet.AppointmentsResourcesDataTable newChildRecords =
this.schedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Added)
as SchedulerDataDataSet.AppointmentsResourcesDataTable;
SchedulerDataDataSet.AppointmentsResourcesDataTable modifiedChildRecords =
this.schedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Modified)
as SchedulerDataDataSet.AppointmentsResourcesDataTable;
try
{
if (deletedChildRecords != null)
{
appointmentsResourcesTableAdapter.Update(deletedChildRecords);
}
appointmentsTableAdapter.Update(this.schedulerDataDataSet.Appointments);
if (newChildRecords != null)
{
appointmentsResourcesTableAdapter.Update(newChildRecords);
}
if (modifiedChildRecords != null)
{
appointmentsResourcesTableAdapter.Update(modifiedChildRecords);
}
this.schedulerDataDataSet.AcceptChanges();
}
catch (Exception ex)
{
MessageBox.Show(string.Format("An error occurred during the update process:\n{0}", ex.Message));
}
finally
{
if (deletedChildRecords != null)
{
deletedChildRecords.Dispose();
}
if (newChildRecords != null)
{
newChildRecords.Dispose();
}
if (modifiedChildRecords != null)
{
modifiedChildRecords.Dispose();
}
}
}
Private Sub DragDropBehavior_PreviewDragOver(sender As Object, e As Telerik.WinControls.RadDragOverEventArgs)
e.CanDrop = TypeOf e.HitTarget Is RadListElement
End Sub
Private Sub DragDropBehavior_PreviewDragDrop(sender As Object, e As Telerik.WinControls.RadDropEventArgs)
Dim draggedInstance As DragFeedbackElement = TryCast(e.DragInstance, DragFeedbackElement)
If draggedInstance Is Nothing Then
Return
End If
Dim listElement As RadListElement = TryCast(e.HitTarget, RadListElement)
If listElement Is Nothing Then
Return
End If
e.Handled = True
Dim listControl As RadListControl = TryCast(listElement.ElementTree.Control, RadListControl)
Dim targetItem As RadListVisualItem = TryCast(listControl.ElementTree.GetElementAtPoint(e.DropLocation), RadListVisualItem)
Dim indexToInsert As Integer
If targetItem IsNot Nothing Then
indexToInsert = targetItem.Data.RowIndex
Else
indexToInsert = listControl.Items.Count
End If
Dim draggedAppointment As Appointment = TryCast(draggedInstance.AssociatedAppointment, Appointment)
SchedulerUIHelper.DeleteAppointment(draggedAppointment, Me.RadScheduler1)
Dim newItem As New RadListDataItem(draggedAppointment.Summary)
listControl.Items.Insert(indexToInsert, newItem)
'save changes to data base
SaveChanges()
End Sub
Public Sub SaveChanges()
AppointmentsResourcesTableAdapter.Adapter.AcceptChangesDuringUpdate = False
Dim deletedChildRecords As SchedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Deleted), SchedulerDataDataSet.AppointmentsResourcesDataTable)
Dim newChildRecords As SchedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Added), SchedulerDataDataSet.AppointmentsResourcesDataTable)
Dim modifiedChildRecords As SchedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Modified), SchedulerDataDataSet.AppointmentsResourcesDataTable)
Try
If deletedChildRecords IsNot Nothing Then
AppointmentsResourcesTableAdapter.Update(deletedChildRecords)
End If
AppointmentsTableAdapter.Update(Me.SchedulerDataDataSet.Appointments)
If newChildRecords IsNot Nothing Then
AppointmentsResourcesTableAdapter.Update(newChildRecords)
End If
If modifiedChildRecords IsNot Nothing Then
AppointmentsResourcesTableAdapter.Update(modifiedChildRecords)
End If
Me.SchedulerDataDataSet.AcceptChanges()
Catch ex As Exception
MessageBox.Show(String.Format("An error occurred during the update process:" & vbLf & "{0}", ex.Message))
Finally
If deletedChildRecords IsNot Nothing Then
deletedChildRecords.Dispose()
End If
If newChildRecords IsNot Nothing Then
newChildRecords.Dispose()
End If
If modifiedChildRecords IsNot Nothing Then
modifiedChildRecords.Dispose()
End If
End Try
End Sub
Figure 1: Using RadDragDropService
As we remove the dragged appointment,it is necessary to save the performed changes in the data source.Please refer to Data Binding Walkthrough article.
Drag and Drop from RadListControl to RadScheduler Using the OLE Drag and Drop
- Firstly, we should start the drag and drop operation using the RadListControl.MouseMove event when the left mouse button is pressed. Afterwards, allow dragging over the RadScheduler via the Effect argument of the DragEventArgs in the RadScheduler.DragEnter event handler:
private Point mouseDownPosition;
private bool isDragging;
private void radListControl1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button != MouseButtons.Left)
{
this.isDragging = false;
return;
}
if (this.isDragging)
return;
Point currentPosition = e.Location;
if ((Math.Abs((currentPosition.X - this.mouseDownPosition.X)) >= SystemInformation.DragSize.Width) ||
(Math.Abs((currentPosition.Y - this.mouseDownPosition.Y)) >= SystemInformation.DragSize.Height))
{
this.isDragging = true;
DragObject dragObject = new DragObject();
RadListVisualItem draggedItem = this.radListControl1.ElementTree.GetElementAtPoint(currentPosition) as RadListVisualItem;
if (draggedItem != null)
{
string itemText = draggedItem.Text;
if (itemText != string.Empty)
{
dragObject.Values.Add(AppointmentFields.Summary, itemText);
dragObject.Status = AppointmentFields.Summary;
//start the drag and drop operation
(sender as RadListControl).DoDragDrop(dragObject, DragDropEffects.Copy);
}
}
}
}
private void radScheduler1_DragEnter(object sender, DragEventArgs e)
{
DragObject dragObject = e.Data.GetData(typeof(DragObject)) as DragObject;
//allow dragging over the RadScheduler
e.Effect = dragObject == null ? DragDropEffects.None : DragDropEffects.Copy;
}
Private mouseDownPosition As Point
Private isDragging As Boolean
Private Sub radListControl1_MouseMove(sender As Object, e As MouseEventArgs)
If e.Button <> MouseButtons.Left Then
Me.isDragging = False
Return
End If
If Me.isDragging Then
Return
End If
Dim currentPosition As Point = e.Location
If (Math.Abs((currentPosition.X - Me.mouseDownPosition.X)) >= SystemInformation.DragSize.Width) OrElse (Math.Abs((currentPosition.Y - Me.mouseDownPosition.Y)) >= SystemInformation.DragSize.Height) Then
Me.isDragging = True
Dim dragObject As New DragObject()
Dim draggedItem As RadListVisualItem = TryCast(Me.RadListControl1.ElementTree.GetElementAtPoint(currentPosition), RadListVisualItem)
If draggedItem IsNot Nothing Then
Dim itemText As String = draggedItem.Text
If itemText <> String.Empty Then
dragObject.Values.Add(AppointmentFields.Summary, itemText)
dragObject.Status = AppointmentFields.Summary
'start the drag and drop operation
TryCast(sender, RadListControl).DoDragDrop(dragObject, DragDropEffects.Copy)
End If
End If
End If
End Sub
Private Sub radScheduler1_DragEnter(sender As Object, e As DragEventArgs)
Dim dragObject As DragObject = TryCast(e.Data.GetData(GetType(DragObject)), DragObject)
'allow dragging over the RadScheduler
e.Effect = If(dragObject Is Nothing, DragDropEffects.None, DragDropEffects.Copy)
End Sub
2. In the RadScheduler.DragDrop event you need to get the location of the mouse and convert it to a point that the scheduler can use to get the cell element underneath the mouse. This MonthCellElement is passed to a private method GetCellAppointment that we will write next:
private void radScheduler1_DragDrop(object sender, DragEventArgs e)
{
Point point = this.radScheduler1.PointToClient(new Point(e.X, e.Y));
SchedulerCellElement schedulerCell = SchedulerUIHelper.GetCellAtPoint(point, this.radScheduler1);
if (schedulerCell != null)
{
DragObject dragObject = e.Data.GetData(typeof(DragObject)) as DragObject;
if (dragObject != null)
{
Appointment appointment = CreateAppointment(schedulerCell.Date, dragObject);
this.radScheduler1.Appointments.Add(appointment);
int indexToRemove = this.radListControl1.Items.IndexOf(appointment.Summary);
if (indexToRemove > -1)
{
this.radListControl1.Items.RemoveAt(indexToRemove);
}
}
}
this.mouseDownPosition = Point.Empty;
this.isDragging = false;
//save changes to database
SaveChanges();
}
Private Sub radScheduler1_DragDrop(sender As Object, e As DragEventArgs)
Dim point__1 As Point = Me.RadScheduler1.PointToClient(New Point(e.X, e.Y))
Dim schedulerCell As SchedulerCellElement = SchedulerUIHelper.GetCellAtPoint(point__1, Me.RadScheduler1)
If schedulerCell IsNot Nothing Then
Dim dragObject As DragObject = TryCast(e.Data.GetData(GetType(DragObject)), DragObject)
If dragObject IsNot Nothing Then
Dim appointment As Appointment = CreateAppointment(schedulerCell.[Date], dragObject)
Me.RadScheduler1.Appointments.Add(appointment)
Dim indexToRemove As Integer = Me.RadListControl1.Items.IndexOf(appointment.Summary)
If indexToRemove > -1 Then
Me.RadListControl1.Items.RemoveAt(indexToRemove)
End If
End If
End If
Me.mouseDownPosition = Point.Empty
Me.isDragging = False
'save changes to database
SaveChanges()
End Sub
3. The helper method CreateAppointment() creates an appointment, starting at the cell where the RadListControl item is dropped. This appointment gets its data from the dragged item.
private Appointment CreateAppointment(DateTime currentDate, DragObject dragObject)
{
Appointment appointment = new Appointment();
DateTime startDate = currentDate;
DateTime endDate = currentDate.AddHours(1);
switch (dragObject.Status)
{
case AppointmentFields.Summary:
appointment.Summary = dragObject.Values[dragObject.Status] as string;
break;
case AppointmentFields.Row:
appointment.Summary = dragObject.Values[AppointmentFields.Summary] as string;
appointment.Description = dragObject.Values[AppointmentFields.Description] as string;
appointment.BackgroundId = (int)dragObject.Values[AppointmentFields.Background];
appointment.StatusId = (int)dragObject.Values[AppointmentFields.Status];
appointment.Location = dragObject.Values[AppointmentFields.Location] as string;
startDate = (DateTime)dragObject.Values[AppointmentFields.Start];
endDate = (DateTime)dragObject.Values[AppointmentFields.End];
TimeSpan range = endDate - startDate;
endDate = currentDate + range;
startDate = currentDate;
break;
}
appointment.Start = startDate;
appointment.End = endDate;
return appointment;
}
private enum AppointmentFields
{
Row,
Summary,
Location,
Description,
Start,
End,
Background,
Status
}
private class DragObject
{
private AppointmentFields status;
private Dictionary<AppointmentFields, object> values = new Dictionary<AppointmentFields, object>();
public AppointmentFields Status
{
get
{
return this.status;
}
set
{
this.status = value;
}
}
public Dictionary<AppointmentFields, object> Values
{
get
{
return this.values;
}
}
}
Private Function CreateAppointment(currentDate As DateTime, dragObject As DragObject) As Appointment
Dim appointment As New Appointment()
Dim startDate As DateTime = currentDate
Dim endDate As DateTime = currentDate.AddHours(1)
Select Case dragObject.Status
Case AppointmentFields.Summary
appointment.Summary = TryCast(dragObject.Values(dragObject.Status), String)
Exit Select
Case AppointmentFields.Row
appointment.Summary = TryCast(dragObject.Values(AppointmentFields.Summary), String)
appointment.Description = TryCast(dragObject.Values(AppointmentFields.Description), String)
appointment.BackgroundId = CInt(dragObject.Values(AppointmentFields.Background))
appointment.StatusId = CInt(dragObject.Values(AppointmentFields.Status))
appointment.Location = TryCast(dragObject.Values(AppointmentFields.Location), String)
startDate = DirectCast(dragObject.Values(AppointmentFields.Start), DateTime)
endDate = DirectCast(dragObject.Values(AppointmentFields.[End]), DateTime)
Dim range As TimeSpan = endDate - startDate
endDate = currentDate + range
startDate = currentDate
Exit Select
End Select
appointment.Start = startDate
appointment.[End] = endDate
Return appointment
End Function
Private Enum AppointmentFields
Row
Summary
Location
Description
Start
[End]
Background
Status
End Enum
Private Class DragObject
Private m_status As AppointmentFields
Private m_values As New Dictionary(Of AppointmentFields, Object)()
Public Property Status() As AppointmentFields
Get
Return Me.m_status
End Get
Set(value As AppointmentFields)
Me.m_status = value
End Set
End Property
Public ReadOnly Property Values() As Dictionary(Of AppointmentFields, Object)
Get
Return Me.m_values
End Get
End Property
End Class
Figure 2: OLE Drag and Drop
