78 lines
1.9 KiB
VB.net
78 lines
1.9 KiB
VB.net
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Namespace Undo
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Public Class CommandManager
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Protected Property UndoCommands As New Stack(Of ICommand)
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Protected Property RedoCommands As New Stack(Of ICommand)
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''' <summary>
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''' 运行命令，并将命令添加至撤销堆栈
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''' </summary>
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''' <param name="command"></param>
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Public Sub RunCommand(command As ICommand)
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command.Execute()
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AddUndoCommand(command)
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End Sub
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''' <summary>
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''' 将命令添加至撤销堆栈
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''' </summary>
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Public Sub AddUndoCommand(command As ICommand)
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UndoCommands.Push(command)
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If RedoCommands.Count > 0 Then
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ClearRedoCommands()
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End If
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End Sub
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''' <summary>
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''' 清空撤销命令堆栈
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''' </summary>
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Public Sub ClearUndoCommands()
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UndoCommands.Clear()
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End Sub
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''' <summary>
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''' 清空重做命令堆栈
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''' </summary>
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Public Sub ClearRedoCommands()
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RedoCommands.Clear()
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End Sub
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''' <summary>
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''' 清空撤销与重做命令堆栈
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''' </summary>
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Public Sub ClearCommands()
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ClearUndoCommands()
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ClearRedoCommands()
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End Sub
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''' <summary>
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''' 执行撤销命令
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''' </summary>
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Public Sub Undo()
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If UndoCommands.Count <= 0 Then Return
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Dim command As ICommand = UndoCommands.Pop()
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command.Undo()
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RedoCommands.Push(command)
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End Sub
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''' <summary>
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''' 执行重做命令
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''' </summary>
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Public Sub Redo()
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If RedoCommands.Count <= 0 Then Return
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Dim command As ICommand = RedoCommands.Pop()
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command.Redo()
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UndoCommands.Push(command)
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'MemberwiseClone()‘浅拷贝
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End Sub
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End Class
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End Namespace
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