Multiple undo / Redo

Question

How do I have multiple undo & redo function with my following code ?

private void btn_Undo_Click(object sender, EventArgs e) //To Undo previous searched record
    {
        if (_dataSet != null && _dataSet.Tables.Count > 0 && _lastDtTable2 != null)
        {
            _dataSet.Tables.Clear();
            _dataSet.Tables.Add(_lastDtTable2);
            dataGridView1.DataSource = _dataSet.Tables[0];
        }
    }
    private void btn_Redo_Click_2(object sender, EventArgs e)
    {
        if (_dataSet != null && _dataSet.Tables.Count > 0 && _lastDtTable2 != null)
        {
            _dataSet.Tables.Add();
            dataGridView1.DataSource = _dataSet.Tables[0];
        }

I only can undo once

score 0 · Answer 1 · answered Apr 21 '14 at 07:49

0

To maintain multpile undo's you will need to use a structure(e.g. a Stack is a good one), and keep the users history.

Each action is "pushed" into the stack.

Each time he presses "back", you simple "pop" the old state and do what you want with it.

answered Apr 21 '14 at 07:49

Amir Popovich

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For redo a 2nd stack is needed. – TaW Apr 21 '14 at 08:22
Yup..You need to maintain the states in a structure. – Amir Popovich Apr 21 '14 at 08:23
So what should I do ? Can you get me started with the code ? – user3555674 Apr 22 '14 at 00:50

Multiple undo / Redo

1 Answers1