撤消/重做Listview LabelEdit和复选框选择

Question

我已经完成了这个用户控件，并在某些人的帮助下集成了 UndoRedo Manager 。

目前它只能在你添加或删除项目时撤消/重做，而这就是全部，但我想实现LabelEdit undo / redo和checkbox undo / redo。

PS：请注意，Listview_Action需要ListviewItem

这是Undo / Redo管理器Class，不是完整的代码，只是必要的。

我需要在此类中执行哪些更改才能添加我需要的改进？

如果有人可以向我展示一个完整的代码示例，我将不胜感激。

Public Class myListView : Inherits ListView

    Public Event ItemAdded As EventHandler(Of ItemAddedEventArgs)
    Public Class ItemAddedEventArgs : Inherits EventArgs
        Property Item As ListViewItem
    End Class

    Public Event ItemRemoved As EventHandler(Of ItemRemovedEventArgs)
    Public Class ItemRemovedEventArgs : Inherits EventArgs
        Property Item As ListViewItem
    End Class

#Region " Undo/Redo Manager "

    ''' <summary>
    ''' Enable or disble the Undo/Redo monitoring.
    ''' </summary>
    Public Property Enable_UndoRedo_Manager As Boolean = False

    ' Stacks to store Undo/Redo actions.
    Private Property Undostack As New Stack(Of ListView_Action)
    Private Property Redostack As New Stack(Of ListView_Action)

    ' Flags to check if it is doing a Undo/Redo operation.
    Private IsDoingUndo As Boolean = False
    Private IsDoingRedo As Boolean = False

    ' Delegate to Add an Item for Undo/Redo operations.
    Private Delegate Sub AddDelegate(item As ListViewItem)

    ' Delegate to Remove an Item for Undo/Redo operations.
    Private Delegate Sub RemoveDelegate(item As ListViewItem)

    ' The Undo/Redo action.
    Private action As ListView_Action = Nothing

    ' The operation.
    Public Enum Operation As Short
        Undo = 0
        Redo = 1
    End Enum

    ' The method for the Undo/Redo operation.
    Public Enum Method As Short
        Add = 0
        Remove = 1
    End Enum

    ''' <summary>
    ''' Creates a Undo/Redo Action.
    ''' </summary>
    Class ListView_Action

        ''' <summary>
        ''' Names the Undo/Redo Action.
        ''' </summary>
        Property Name As String

        ''' <summary>
        ''' Points to a method to excecute.
        ''' </summary>
        Property Operation As [Delegate]

        ''' <summary>
        ''' Method of the Undo/Redo operation.
        ''' </summary>
        Property Method As Method

        ''' <summary>
        ''' Data Array for the method to excecute.
        ''' </summary>
        Property Data As ListViewItem

    End Class

    ''' <summary>
    ''' This event is raised after an Undo/Redo action is performed.
    ''' </summary>
    Public Event UndoRedo_IsPerformed As EventHandler(Of UndoneRedoneEventArgs)
    Public Class UndoneRedoneEventArgs : Inherits EventArgs
        Property Operation As Operation
        Property Method As Method
        Property Item As ListViewItem
        Property UndoStack As Stack(Of ListView_Action)
        Property RedoStack As Stack(Of ListView_Action)
    End Class

    ''' <summary>
    ''' This event is raised when Undo/Redo Stack size changed.
    ''' </summary>
    Public Event UndoRedo_StackSizeChanged As EventHandler(Of StackSizeChangedEventArgs)
    Public Class StackSizeChangedEventArgs : Inherits EventArgs
        Property UndoStack As Stack(Of ListView_Action)
        Property RedoStack As Stack(Of ListView_Action)
        Property UndoStackIsEmpty As Boolean
        Property RedoStackIsEmpty As Boolean
    End Class

    ''' <summary>
    ''' Undo the last action.
    ''' </summary>
    Public Sub Undo()

        If Me.Undostack.Count = 0 Then Exit Sub ' Nothing to Undo.

        Me.IsDoingUndo = True
        Me.action = Me.Undostack.Pop ' Get the Action from the Stack and remove it.
        Me.action.Operation.DynamicInvoke(Me.action.Data) ' Invoke the undo Action.
        Me.IsDoingUndo = False

        Raise_UndoRedo_IsPerformed(Operation.Undo, Me.action.Method, Me.action.Data)

    End Sub

    ''' <summary>
    ''' Redo the last action.
    ''' </summary>
    Public Sub Redo()

        If Me.Redostack.Count = 0 Then Exit Sub ' Nothing to Redo.

        Me.IsDoingRedo = True
        Me.action = Me.Redostack.Pop() ' Get the Action from the Stack and remove it.
        Me.action.Operation.DynamicInvoke(Me.action.Data) ' Invoke the redo Action.
        Me.IsDoingRedo = False

        Raise_UndoRedo_IsPerformed(Operation.Redo, Me.action.Method, Me.action.Data)

    End Sub

    ' Reverses an Undo/Redo action
    Private Function GetReverseAction(ByVal e As UndoneRedoneEventArgs) As ListView_Action

        Me.action = New ListView_Action

        Me.action.Name = e.Item.Text
        Me.action.Data = e.Item

        Me.action.Operation = If(e.Method = Method.Add, _
                        New RemoveDelegate(AddressOf Me.RemoveItem), _
                        New AddDelegate(AddressOf Me.AddItem))

        Me.action.Method = If(e.Method = Method.Add, _
                     Method.Remove, _
                     Method.Add)

        Return Me.action

    End Function

    ' Raises the "UndoRedo_IsPerformed" Event
    Private Sub Raise_UndoRedo_IsPerformed(ByVal Operation As Operation, _
                                           ByVal Method As Method, _
                                           ByVal Item As ListViewItem)

        RaiseEvent UndoRedo_IsPerformed(Me, New UndoneRedoneEventArgs _
                   With {.Item = Item, _
                         .Method = Method, _
                         .Operation = Operation, _
                         .UndoStack = Me.Undostack, _
                         .RedoStack = Me.Redostack})

        Raise_UndoRedo_StackSizeChanged()

    End Sub

    ' Raises the "UndoRedo_StackSizeChanged" Event
    Private Sub Raise_UndoRedo_StackSizeChanged()

        RaiseEvent UndoRedo_StackSizeChanged(Me, New StackSizeChangedEventArgs _
                   With {.UndoStack = Me.Undostack, _
                         .RedoStack = Me.Redostack, _
                         .UndoStackIsEmpty = Me.Undostack.Count = 0, _
                         .RedoStackIsEmpty = Me.Redostack.Count = 0})

    End Sub

    ' This handles when an Undo or Redo operation is performed.
    Private Sub UndoneRedone(ByVal sender As Object, ByVal e As UndoneRedoneEventArgs) _
    Handles Me.UndoRedo_IsPerformed

        Select Case e.Operation

            Case Operation.Undo
                ' Create a Redo Action for the undone action.
                Me.Redostack.Push(GetReverseAction(e))

            Case Operation.Redo
                ' Create a Undo Action for the redone action.
                Me.Undostack.Push(GetReverseAction(e))

        End Select

    End Sub

    ' Monitors when an Item is added to create an Undo Operation.
    Private Sub OnItemAdded(sender As Object, e As ItemAddedEventArgs) _
    Handles Me.ItemAdded

        If Me.Enable_UndoRedo_Manager _
            AndAlso (Not Me.IsDoingUndo And Not Me.IsDoingRedo) Then

            Me.Redostack.Clear()

            ' // Crate an Undo Action
            Me.action = New ListView_Action
            Me.action.Name = e.Item.Text
            Me.action.Operation = New RemoveDelegate(AddressOf Me.RemoveItem)
            Me.action.Data = e.Item
            Me.action.Method = Method.Remove

            Me.Undostack.Push(action)

            Raise_UndoRedo_StackSizeChanged()

        End If

    End Sub

    ' Monitors when an Item is removed to create an Undo Operation.
    Private Sub OnItemRemoved(sender As Object, e As ItemRemovedEventArgs) _
    Handles Me.ItemRemoved

        If Me.Enable_UndoRedo_Manager _
            AndAlso (Not Me.IsDoingUndo And Not Me.IsDoingRedo) Then

            Me.Redostack.Clear()

            ' // Crate an Undo Action
            Me.action = New ListView_Action
            Me.action.Name = e.Item.Text
            Me.action.Operation = New AddDelegate(AddressOf Me.AddItem)
            Me.action.Data = e.Item
            Me.action.Method = Method.Add

            Me.Undostack.Push(action)

            Raise_UndoRedo_StackSizeChanged()

        End If

    End Sub

#End Region

End Class

Answer 1

首先，因为您从派生类开始，所以将这些事件添加到它：

' (your Item events still lack a Sender and Item to save a lot of work)
Public Event CheckChanged(ByVal sender As Object, _
           ByVal lice As ListItemCheckChangedArgs)
Public Shadows Event BeforeLabelEdit(ByVal sender As Object, _
           ByVal oldText As String)

需要BeforeLabelEdit，因为基本LV在开始时将旧标签文本存储为Nothing，您需要将其更改为.Text属性以实际检测更改。接下来，观察文本更改将要求您执行与ItemAdded不同的操作（无论是通用还是内部）。

当Before...触发时，存储副本......观察者会将_BeforeText与_AfterText（观察正常的AfterLabelEdit事件）进行比较，如果它们不同，则将_BEforeText推入堆栈。

CheckChanged有点作弊。您可以直接单击LVItem Check，而不会触发任何类型的Enter / GotFocus等事件。这意味着观察者无法获得_BeforeChecked值。原生的LV ItemChecked确实触发了，我只是重新组织它的args，将我需要的东西传递给Watcher（通过上面的事件）。虱子：

Public Class ListItemCheckChangedArgs
    Public Index As Integer                ' index of item checked
    Public OldValue As CheckState          
    Public NewValue As CheckState

    Public Sub New(ByVal ndx As Integer, ByVal ov As CheckState, _
            ByVal nv As CheckState)
        Index = ndx
        OldValue = ov
        NewValue = nv

    End Sub
End Class

观察者然后使用OldValue作为数据创建一个UnDoAction对象。即使没有观察者，这也有助于捕捉您的需求。

重要的部分是Undo类（内部UM会有所不同）：

 Public Class ListViewEUndo
    '... WHO this action applies to
    Friend Ctl As ListViewEX

    ' a listview item, or string (Text) or bool (Check)
    Friend UnDoData As Object

    Friend LVActionType As LVEActionType = LVEActionType.None

    ' original index of items removed / index of item checked
    Friend Index As Integer = -1

  Public Sub New(ByVal _ctl As ListViewEX, ByVal _LvAType As LVEActionType, _
            ByVal _data As Object)
        Ctl = _ctl
        LVActionType = _LvAType
        UnDoData = _data

  End Sub
    ...

LVEActionType只是AddItem，RemoveItem等（这个动作类型是什么）

你可以设计一个基类，然后为TextUndo，CheckUndo和ItemUndo继承它。抛出这个或由此产生的短SELECT CASE语句是否更好。最后，没有DELEGATES，因为UndoManager类/帮助程序将自己应用更改而不是将工作导出到from或control（这也有助于避免推动由撤消/重做操作引起的操作！）。

我不确定它是full code example，但可能会对你的问题有所帮助，具体取决于它是否是内部的（内部几乎不需要任何事件 - 主要需要触发Watcher操作 - 在值之前捕获，捕获/比较后值，响应Add / RemoveItem等）。