在 VB.Net 中创建 undo/redo 文本框算法

Question

我很想在 VB.Net 中创建一个类型算法 Undo/Redo，首先至少我想撤消。

如果我们有例子Textbox1.Text = a,b,c

然后改成=a,b,c,e

然后改为=a,b,c,f

当我点击undo时我要显示（也就是之前的值。之前a,b, c, f之后，是a, b, c,e

a,b,c,e

当我再次点击时我想显示

a,b,c

即undo / redo algorithm的附加值

我首先创建了一个全局列表。

Public Module Globals
    Public Undo As New List(Of String)
End Module

如果列表中不存在文本框值，那么我会添加它。

Private Sub Button1(sender As Object, e As EventArgs) Handles Button1.Click
    If Undo IsNot TextBox1.Text Then
        Undo.Add(TextBox1.Text)
    End If
End Sub

嘿，这是棘手的部分

Private Sub Undo_Click(sender As Object, e As EventArgs) Handles Undo.Click
    Dim i as integer = Undo.Count
    While TextBox1.Text IsNot Undo(i)
        TextBox1.Text = Undo(i)
    End While
 End Sub

   For i As Integer = Undo.Count To 0 Step -1
     TextBox1.Text = Undo(i)
   Next

不幸的是，在这种情况下没有这样的循环。

Answer 1

试试这个：

Private Undos As List(Of String) = New List(Of String)()
Private AddUndo As Boolean = True

Private Sub textBox1_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
    If AddUndo = True Then
        Undos.Add(textBox1.Text)
    End If
End Sub

Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    If Undos.Count <> 0 Then
        AddUndo = False

        If Undos.Count > 1 Then
            textBox1.Text = Undos(Undos.Count - 2)
            Undos.RemoveAt(Undos.Count - 1)
        Else
            textBox1.Text = ""
            Undos.RemoveAt(0)
        End If

        AddUndo = True
    End If
End Sub

在 VB.Net 中创建 undo/redo 文本框算法

Create a undo/redo textboxes algorithm in VB.Net

vb.net