WorkflowView.AddDesignerMessageFilter(WorkflowDesignerMessageFilter) Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Adds a WorkflowDesignerMessageFilter to the WorkflowView.
public:
void AddDesignerMessageFilter(System::Workflow::ComponentModel::Design::WorkflowDesignerMessageFilter ^ designerMessageFilter);
public void AddDesignerMessageFilter (System.Workflow.ComponentModel.Design.WorkflowDesignerMessageFilter designerMessageFilter);
member this.AddDesignerMessageFilter : System.Workflow.ComponentModel.Design.WorkflowDesignerMessageFilter -> unit
Public Sub AddDesignerMessageFilter (designerMessageFilter As WorkflowDesignerMessageFilter)
Parameters
- designerMessageFilter
- WorkflowDesignerMessageFilter
The WorkflowDesignerMessageFilter to add to the WorkflowView.
Examples
In the following example, a WorkflowDesignerLoader is created and a WorkflowView object is associated with the workflow design surface. In order to retrieve notifications of messages, a WorkflowDesignerMessageFilter is created and added to the WorkflowView object.
This code example is part of the Outlook Workflow Wizard SDK Sample from the WorkflowViewWrapper.cs file. For more information, see Outlook Workflow Wizard Sample.
public WorkflowViewWrapper()
{
this.loader = new Loader();
// Create a Workflow Design Surface
this.surface = new DesignSurface();
this.surface.BeginLoad(this.loader);
// Get the Workflow Designer Host
this.Host = this.surface.GetService(typeof(IDesignerHost)) as IDesignerHost;
if (this.Host == null)
return;
// Create a Sequential Workflow by using the Workflow Designer Host
SequentialWorkflow = (SequentialWorkflowActivity)Host.CreateComponent(typeof(SequentialWorkflowActivity));
SequentialWorkflow.Name = "CustomOutlookWorkflow";
// Create a Workflow View on the Workflow Design Surface
this.workflowView = new WorkflowView(this.surface as IServiceProvider);
// Add a message filter to the workflow view, to support panning
MessageFilter filter = new MessageFilter(this.surface as IServiceProvider, this.workflowView);
this.workflowView.AddDesignerMessageFilter(filter);
// Activate the Workflow View
this.Host.Activate();
this.workflowView.Dock = DockStyle.Fill;
this.Controls.Add(workflowView);
this.Dock = DockStyle.Fill;
}
Public Sub New()
Me.loaderValue = New Loader()
' Create a Workflow Design Surface
Me.surface = New DesignSurface()
Me.surface.BeginLoad(Me.loaderValue)
' Get the Workflow Designer Host
If Me.surface.GetService(GetType(IDesignerHost)) IsNot Nothing AndAlso TypeOf Me.surface.GetService(GetType(IDesignerHost)) Is IDesignerHost Then
Me.Host = CType(Me.surface.GetService(GetType(IDesignerHost)), IDesignerHost)
Else
Return
End If
' Create a Sequential Workflow by using the Workflow Designer Host
SequentialWorkflow = CType(Host.CreateComponent(GetType(SequentialWorkflowActivity)), SequentialWorkflowActivity)
SequentialWorkflow.Name = "CustomOutlookWorkflow"
' Create a Workflow View on the Workflow Design Surface
Me.workflowView = New WorkflowView(CType(Me.surface, IServiceProvider))
' Add a message filter to the workflow view, to support panning
Dim filter As MessageFilter = New MessageFilter(CType(Me.surface, IServiceProvider), Me.workflowView)
Me.workflowView.AddDesignerMessageFilter(filter)
' Activate the Workflow View
Me.Host.Activate()
Me.workflowView.Dock = DockStyle.Fill
Me.Controls.Add(workflowView)
Me.Dock = DockStyle.Fill
End Sub
The MessageFilter
object created in the previous code is derived from the WorkflowDesignerMessageFilter class. By overriding the methods of this class, the message filter is notified whenever a user interface event occurs on the WorkflowView object.
internal sealed class MessageFilter : WorkflowDesignerMessageFilter
{
private bool mouseDown;
private IServiceProvider serviceProvider;
private WorkflowView workflowView;
public MessageFilter(IServiceProvider provider, WorkflowView view)
{
this.serviceProvider = provider;
this.workflowView = view;
}
protected override bool OnMouseDown(MouseEventArgs eventArgs)
{
// Allow other components to process this event by not returning true.
this.mouseDown = true;
return false;
}
protected override bool OnMouseMove(MouseEventArgs eventArgs)
{
// Allow other components to process this event by not returning true.
if (this.mouseDown)
{
this.workflowView.ScrollPosition = new Point(eventArgs.X, eventArgs.Y);
}
return false;
}
protected override bool OnMouseUp(MouseEventArgs eventArgs)
{
// Allow other components to process this event by not returning true.
this.mouseDown = false;
return false;
}
protected override bool OnMouseDoubleClick(MouseEventArgs eventArgs)
{
this.mouseDown = false;
return true;
}
protected override bool OnMouseEnter(MouseEventArgs eventArgs)
{
// Allow other components to process this event by not returning true.
this.mouseDown = false;
return false;
}
protected override bool OnMouseHover(MouseEventArgs eventArgs)
{
// Allow other components to process this event by not returning true.
this.mouseDown = false;
return false;
}
protected override bool OnMouseLeave()
{
// Allow other components to process this event by not returning true.
this.mouseDown = false;
return false;
}
protected override bool OnMouseWheel(MouseEventArgs eventArgs)
{
this.mouseDown = false;
return true;
}
protected override bool OnMouseCaptureChanged()
{
// Allow other components to process this event by not returning true.
this.mouseDown = false;
return false;
}
protected override bool OnDragEnter(DragEventArgs eventArgs)
{
return true;
}
protected override bool OnDragOver(DragEventArgs eventArgs)
{
return true;
}
protected override bool OnDragLeave()
{
return true;
}
protected override bool OnDragDrop(DragEventArgs eventArgs)
{
return true;
}
protected override bool OnGiveFeedback(GiveFeedbackEventArgs gfbevent)
{
return true;
}
protected override bool OnQueryContinueDrag(QueryContinueDragEventArgs qcdevent)
{
return true;
}
protected override bool OnKeyUp(KeyEventArgs eventArgs)
{
return true;
}
protected override bool OnShowContextMenu(Point menuPoint)
{
return true;
}
protected override bool OnKeyDown(KeyEventArgs eventArgs)
{
if (eventArgs.KeyCode == Keys.Delete)
{
ISelectionService selectionService = (ISelectionService)this.serviceProvider.GetService(typeof(ISelectionService));
if (selectionService != null && selectionService.PrimarySelection is CodeActivity)
{
CodeActivity codeActivityComponent = (CodeActivity)selectionService.PrimarySelection;
CompositeActivity parentActivity = codeActivityComponent.Parent;
if (parentActivity != null)
{
parentActivity.Activities.Remove(codeActivityComponent);
this.ParentView.Update();
}
}
}
return true;
}
}
Friend Class MessageFilter
Inherits WorkflowDesignerMessageFilter
Private mouseDown As Boolean
Private serviceProvider As IServiceProvider
Private workflowView As WorkflowView
Public Sub New(ByVal provider As IServiceProvider, ByVal view As WorkflowView)
Me.serviceProvider = provider
Me.workflowView = view
End Sub
Protected Overrides Function OnMouseDown(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = True
Return False
End Function
Protected Overrides Function OnMouseMove(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
' Allow other components to process this event by not returning true.
If (Me.mouseDown) Then
Me.workflowView.ScrollPosition = New Point(eventArgs.X, eventArgs.Y)
End If
Return False
End Function
Protected Overrides Function OnMouseUp(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = False
Return False
End Function
Protected Overrides Function OnMouseDoubleClick(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
Me.mouseDown = False
Return True
End Function
Protected Overrides Function OnMouseEnter(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = False
Return False
End Function
Protected Overrides Function OnMouseHover(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = False
Return False
End Function
Protected Overrides Function OnMouseLeave() As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = False
Return False
End Function
Protected Overrides Function OnMouseWheel(ByVal eventArgs As System.Windows.Forms.MouseEventArgs) As Boolean
Me.mouseDown = False
Return True
End Function
Protected Overrides Function OnMouseCaptureChanged() As Boolean
' Allow other components to process this event by not returning true.
Me.mouseDown = False
Return False
End Function
Protected Overrides Function OnDragEnter(ByVal eventArgs As System.Windows.Forms.DragEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnDragOver(ByVal eventArgs As System.Windows.Forms.DragEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnDragLeave() As Boolean
Return True
End Function
Protected Overrides Function OnDragDrop(ByVal eventArgs As System.Windows.Forms.DragEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnGiveFeedback(ByVal eventArgs As System.Windows.Forms.GiveFeedbackEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnQueryContinueDrag(ByVal eventArgs As System.Windows.Forms.QueryContinueDragEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnKeyUp(ByVal eventArgs As System.Windows.Forms.KeyEventArgs) As Boolean
Return True
End Function
Protected Overrides Function OnShowContextMenu(ByVal screenMenuPoint As System.Drawing.Point) As Boolean
Return True
End Function
Protected Overrides Function OnKeyDown(ByVal eventArgs As System.Windows.Forms.KeyEventArgs) As Boolean
If eventArgs.KeyCode = Keys.Delete Then
Dim selectionService As ISelectionService = CType(Me.serviceProvider.GetService(GetType(ISelectionService)), ISelectionService)
If selectionService IsNot Nothing AndAlso TypeOf selectionService.PrimarySelection Is CodeActivity Then
Dim codeActivityComponent As CodeActivity = CType(selectionService.PrimarySelection, CodeActivity)
Dim parentActivity As CompositeActivity = codeActivityComponent.Parent
If parentActivity IsNot Nothing Then
parentActivity.Activities.Remove(codeActivityComponent)
Me.ParentView.Update()
End If
End If
End If
Return True
End Function
End Class
Remarks
A WorkflowDesignerMessageFilter is a component that handles messages from the WorkflowView.
Using the Strategy
design pattern, the WorkflowView will pass messages to the WorkflowDesignerMessageFilter to be handled.
Mouse events, keyboard events, paint and layout events are passed on to a WorkflowDesignerMessageFilter associated with the WorkflowView.