Classe Task
Representa uma coleção de comandos e ligações de entrada para esses comandos.
Namespace: Microsoft.Windows.Design.Interaction
Assembly: Microsoft.Windows.Design.Interaction (em Microsoft.Windows.Design.Interaction.dll)
Sintaxe
Public Class Task
Dim instance As Task
public class Task
public ref class Task
public class Task
Comentários
A Task representa uma coleção de ligações de entrada e comandos que podem ser associados a um elemento da interface do usuário no designer. Quando uma tarefa estiver ativo, todos os usuário entrada é direcionada para a tarefa e comandos que estão associados com ligações de entrada podem ser executados.Quando a tarefa é desativada, a entrada do usuário voltará ao normal.
Você pode adornam uma tarefa com RequiresServiceAttribute e RequiresContextItemAttribute atributos. Se você fizer isso, a tarefa não será usada a menos que os serviços e itens de contexto estão disponível.
Exemplos
O exemplo de código a seguir mostra como usar o Task classe. Para obter mais informações, consulte Como: Criar uma diretiva substituto.
Imports System
Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Input
Imports Microsoft.Windows.Design.Interaction
' A DockPanelMarginTask is attached to to the adorner
' offered by the DockPanelAdornerProvider class. When
' you drag the adorner, the target control's Margin
' property changes.
Class DockPanelMarginTask
Inherits Task
Private dragBinding, endDragBinding As InputBinding
Private initialMargin As Thickness
' The DockPanelMarginTask constructor establishes mappings
' between user inputs and commands.
Public Sub New()
Dim beginDrag As New ToolCommand("BeginDrag")
Dim drag As New ToolCommand("Drag")
Dim endDrag As New ToolCommand("EndDrag")
Dim resetMargins As New ToolCommand("ResetMargins")
Me.InputBindings.Add(New InputBinding( _
beginDrag, _
New ToolGesture(ToolAction.DragIntent, MouseButton.Left)))
Me.InputBindings.Add( _
New InputBinding( _
resetMargins, _
New ToolGesture(ToolAction.DoubleClick, MouseButton.Left)))
Me.dragBinding = New InputBinding( _
drag, _
New ToolGesture(ToolAction.Move))
Me.endDragBinding = New InputBinding( _
endDrag, _
New ToolGesture(ToolAction.DragComplete))
Me.ToolCommandBindings.Add(New ToolCommandBinding(beginDrag, AddressOf OnBeginDrag))
Me.ToolCommandBindings.Add(New ToolCommandBinding(drag, AddressOf OnDrag))
Me.ToolCommandBindings.Add(New ToolCommandBinding(endDrag, AddressOf OnEndDrag))
Me.ToolCommandBindings.Add(New ToolCommandBinding(resetMargins, AddressOf OnResetMargins))
End Sub
Private Sub OnBeginDrag(ByVal sender As Object, ByVal args As ExecutedToolEventArgs)
Dim data As GestureData = GestureData.FromEventArgs(args)
Me.BeginFocus(data)
Me.InputBindings.Add(dragBinding)
Me.InputBindings.Add(endDragBinding)
Me.initialMargin = CType(data.ImpliedSource.Properties(FrameworkElement.MarginProperty).ComputedValue, Thickness)
End Sub
Private Sub OnDrag(ByVal sender As Object, ByVal args As ExecutedToolEventArgs)
Dim data As MouseGestureData = MouseGestureData.FromEventArgs(args)
Dim offX As Double = data.PositionDelta.X
Dim offY As Double = data.PositionDelta.Y
Dim newMargin As Thickness = initialMargin
newMargin.Bottom += offY
newMargin.Top += offY
newMargin.Left += offX
newMargin.Right += offX
data.ImpliedSource.Properties(FrameworkElement.MarginProperty).SetValue(newMargin)
End Sub
Private Sub OnEndDrag(ByVal sender As Object, ByVal args As ExecutedToolEventArgs)
Description = "Adjust margin"
Me.Complete()
End Sub
Protected Overrides Sub OnCompleted(ByVal e As EventArgs)
Me.Cleanup()
MyBase.OnCompleted(e)
End Sub
Protected Overrides Sub OnReverted(ByVal e As EventArgs)
Me.Cleanup()
MyBase.OnReverted(e)
End Sub
Private Sub Cleanup()
Me.InputBindings.Remove(dragBinding)
Me.InputBindings.Remove(endDragBinding)
End Sub
Private Sub OnResetMargins(ByVal sender As Object, ByVal args As ExecutedToolEventArgs)
Dim data As GestureData = GestureData.FromEventArgs(args)
data.ImpliedSource.Properties(FrameworkElement.MarginProperty).ClearValue()
End Sub
End Class
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Input;
using Microsoft.Windows.Design.Interaction;
namespace DemoControlLibrary.VisualStudio.Design
{
// A DockPanelMarginTask is attached to to the adorner
// offered by the DockPanelAdornerProvider class. When
// you drag the adorner, the target control's Margin
// property changes.
class DockPanelMarginTask : Task
{
InputBinding dragBinding, endDragBinding;
Thickness initialMargin;
// The DockPanelMarginTask constructor establishes mappings
// between user inputs and commands.
public DockPanelMarginTask()
{
ToolCommand beginDrag = new ToolCommand("BeginDrag");
ToolCommand drag = new ToolCommand("Drag");
ToolCommand endDrag = new ToolCommand("EndDrag");
ToolCommand resetMargins = new ToolCommand("ResetMargins");
this.InputBindings.Add(
new InputBinding(
beginDrag,
new ToolGesture(ToolAction.DragIntent, MouseButton.Left)));
this.InputBindings.Add(
new InputBinding(
resetMargins,
new ToolGesture(ToolAction.DoubleClick, MouseButton.Left)));
this.dragBinding = new InputBinding(
drag,
new ToolGesture(ToolAction.Move));
this.endDragBinding = new InputBinding(
endDrag,
new ToolGesture(ToolAction.DragComplete));
this.ToolCommandBindings.Add(
new ToolCommandBinding(beginDrag, OnBeginDrag));
this.ToolCommandBindings.Add(
new ToolCommandBinding(drag, OnDrag));
this.ToolCommandBindings.Add(
new ToolCommandBinding(endDrag, OnEndDrag));
this.ToolCommandBindings.Add(
new ToolCommandBinding(resetMargins, OnResetMargins));
}
private void OnBeginDrag(object sender, ExecutedToolEventArgs args)
{
GestureData data = GestureData.FromEventArgs(args);
this.BeginFocus(data);
this.InputBindings.Add(dragBinding);
this.InputBindings.Add(endDragBinding);
this.initialMargin = (Thickness)data.ImpliedSource.Properties[
FrameworkElement.MarginProperty].ComputedValue;
}
private void OnDrag(object sender, ExecutedToolEventArgs args)
{
MouseGestureData data = MouseGestureData.FromEventArgs(args);
double offX = data.PositionDelta.X;
double offY = data.PositionDelta.Y;
Thickness newMargin = initialMargin;
newMargin.Bottom += offY;
newMargin.Top += offY;
newMargin.Left += offX;
newMargin.Right += offX;
data.ImpliedSource.Properties[FrameworkElement.MarginProperty].SetValue(newMargin);
}
private void OnEndDrag(object sender, ExecutedToolEventArgs args)
{
Description = "Adjust margin";
this.Complete();
}
protected override void OnCompleted(EventArgs e)
{
this.Cleanup();
base.OnCompleted(e);
}
protected override void OnReverted(EventArgs e)
{
this.Cleanup();
base.OnReverted(e);
}
private void Cleanup()
{
this.InputBindings.Remove(dragBinding);
this.InputBindings.Remove(endDragBinding);
}
private void OnResetMargins(object sender, ExecutedToolEventArgs args)
{
GestureData data = GestureData.FromEventArgs(args);
data.ImpliedSource.Properties[FrameworkElement.MarginProperty].ClearValue();
}
}
}
Hierarquia de herança
System.Object
Microsoft.Windows.Design.Interaction.Task
Acesso thread-safe
Quaisquer membros static (Shared no Visual Basic) públicos deste tipo são thread-safe. Não há garantia de que qualquer membro de instância seja thread-safe.
Consulte também
Referência
Namespace Microsoft.Windows.Design.Interaction