Task 類別
更新:2007 年 11 月
表示命令集合和這些命令的輸入繫結。
命名空間: Microsoft.Windows.Design.Interaction
組件: Microsoft.Windows.Design.Interaction (在 Microsoft.Windows.Design.Interaction.dll 中)
語法
Public Class Task
Dim instance As Task
public class Task
public ref class Task
public class Task
備註
Task 表示可與設計工具中使用者介面項目相關聯的一組輸入繫結和命令。當工作在作用中時,所有使用者輸入都會導向到該工作,而與輸入繫結相關聯的命令便可執行。當工作停用時,使用者輸入就會回復正常。
您可以使用 RequiresServiceAttribute 和 RequiresContextItemAttribute 屬性來裝飾工作。如果這樣做,除非取得必要的服務和內容項目,否則不會使用工作。
範例
下列程式碼範例會示範如何使用 Task 類別。如需詳細資訊,請參閱 HOW TO:建立 Surrogate 原則。
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();
}
}
}
繼承階層架構
System.Object
Microsoft.Windows.Design.Interaction.Task
執行緒安全
這個型別的任何 Public static (在 Visual Basic 中為 Shared) 成員都具備執行緒安全。並非所有的執行個體成員都是安全執行緒。
請參閱
參考
Microsoft.Windows.Design.Interaction 命名空間