#眉標=.NET
#副標=.NET Namespace專欄
#大標= System.Collections(上) 從存放資料開始
#作者=文／彭靖灝


 
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程式 1 利用Stack 類別提供復原能力

Private myStack As New Stack

Private Sub btnDelete_Click(ByVal sender As
System.Object, _
    ByVal e As System.EventArgs) Handles 
btnDelete.Click
    Dim objAction As New Action
    With objAction
        .Name = "DELETE"
        .Target = "Paragraph(3)"
        .Position = "NA"
    End With
    myStack.Push(objAction)
    lstActions.Items.Add("DELETE Paragraph(3)")
End Sub

Private Sub btnInsert_Click(ByVal sender As 
System.Object, _
ByVal e As System.EventArgs) Handles btnInsert.Click
    Dim objAction As New Action
    With objAction
        .Name = "INSERT BEFORE"
        .Target = "Character(A)"
        .Position = "Paragraph(2)"
    End With
    myStack.Push(objAction)
    lstActions.Items.Add( _
        "INSERT Character(A) BEFORE 
Paragraph(2)")
End Sub

Private Sub btnModify_Click(ByVal sender As 
System.Object, _
    ByVal e As System.EventArgs) Handles 
btnModify.Click
    Dim objAction As New Action
    With objAction
        .Name = "MODIFY FORMAT"
        .Target = "FormatTemplate(2)"
        .Position = "Paragraph(5)"
    End With
    myStack.Push(objAction)
    lstActions.Items.Add( _
        "MODIFY FORMAT Paragraph(5) TO " & _
        "FormatTemplate(2)")
End Sub

Private Sub btnUndo_Click(ByVal sender As 
System.Object, _
    ByVal e As System.EventArgs) Handles 
btnUndo.Click
    Dim objAction As Action
    txtUndo.Text = ""
    Do While myStack.Count > 0
        objAction = myStack.Pop
        txtUndo.Text &= objAction.Undo & _
            ControlChars.NewLine
    Loop
End Sub
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程式 2 另一個取用堆疊成員的方式
Private Sub btnUndo2_Click(ByVal sender As 
System.Object, _
    ByVal e As System.EventArgs) Handles 
btnUndo2.Click
    Dim objaction As Action
    txtUndo.Text = ""
    For Each objaction In myStack
        txtUndo.Text &= objaction.Undo & _
            ControlChars.NewLine
    Next
End Sub
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