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I am using the following code in order to implement undo/redo into my application:

    public struct UndoSection
    {
        public string Undo;
        public int Index;   
}

--

 public UndoSection(int index, string undo)
    {
        Index = index;
        Undo = undo;
    }

--

            Stack<UndoSection> UndoStack = new Stack<UndoSection>();
 private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Modifiers == Keys.None && e.KeyCode == Keys.Delete)
                UndoStack.Push(new UndoSection(richTextBoxPrintCtrl1.SelectionStart, richTextBoxPrintCtrl1.SelectedText));
            else if (e.Control && e.KeyCode == Keys.Z)
            {
                e.Handled = true;
                undo_Click(richTextBoxPrintCtrl1, new EventArgs());
            }
        }

     public string[] RTBRedoUndo;
        public int StackCount = 0;
        public int OldLength = 0;
        public int ChangeToSave = 5;
        public bool IsRedoUndo = false;

--

    public void RTBTextChanged()
    {
        if (richTextBoxPrintCtrl1.TextLength - OldLength >= ChangeToSave | richTextBoxPrintCtrl1.TextLength - OldLength <= ChangeToSave)
        {
            StackCount += 1;
            RTBRedoUndo[StackCount] = richTextBoxPrintCtrl1.Text;
        }
    }

    public void UndoCode()
    {
        IsRedoUndo = true;
        if (StackCount > 0 && RTBRedoUndo[StackCount - 1] != null)
        {
            StackCount = StackCount - 1;
            richTextBoxPrintCtrl1.Text = RTBRedoUndo[StackCount];
        }
    }

    public void RedoCode()
    {
        if (IsRedoUndo == false && richTextBoxPrintCtrl1.Text.Substring(richTextBoxPrintCtrl1.Text.Length - 1, 1) == " ")

            IsRedoUndo = true;
        if (StackCount > 0 && RTBRedoUndo[StackCount + 1] != null)
        {
            StackCount = StackCount + 1;
            richTextBoxPrintCtrl1.Text = RTBRedoUndo[StackCount];
        }

However, if I type some text in my rich text box such as: "Hello. This is my application.", It will only let me redo up to "my". It won't let me redo "application.". And if I undo all text, I then cannot redo and restore the text.

What is causing this to behave in this manner? I really need to get this undo/redo code working correct. Could somebody help point me in the right direction, please?

--EDIT--

Redo code:

public void RedoCode()
    {
        if (IsRedoUndo == false && richTextBoxPrintCtrl1.Text.Substring(richTextBoxPrintCtrl1.Text.Length - 1, 1) == " ")

            IsRedoUndo = true;
        if (StackCount > 0 && RTBRedoUndo[StackCount + 1] != null)
        {
            StackCount = StackCount + 1;
            richTextBoxPrintCtrl1.Text = RTBRedoUndo[StackCount];
        }

    }

It is called by a button click, using RedoCode();

Toby
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1 Answers1

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Can you show how to call the Redo function?

as from what I can see you've missed out the below code

 private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Modifiers == Keys.None && e.KeyCode == Keys.Delete)
                UndoStack.Push(new UndoSection(richTextBoxPrintCtrl1.SelectionStart, richTextBoxPrintCtrl1.SelectedText));
            else if (e.Control && e.KeyCode == Keys.Z)
            {
                e.Handled = true;
                undo_Click(richTextBoxPrintCtrl1, new EventArgs());
            }
            else if (e.Control && e.KeyCode == Keys.Y)
            {
                e.Handled = true;
                redo_Click(richTextBoxPrintCtrl1, new EventArgs());
            }
kanoth
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