Question

Okai, let’s say we have:

• 2 Textboxes (textBox1, textBox2)
• 1 Button (button1)
• A List (list1)

What I’m trying to do is to store the text that has been entered in textBox1 to list1 so I can easily retrieve my previous input. The text from textBox1 will be written to list1 when I press the button. this is the code that I have so far:

    private static List<string> list1 = new List<string>();

    list1.Add(textBox1.Text); // <-- On the button click event.

private void ServerInputtextboxCommand_KeyDown(object sender, KeyEventArgs e)
    {
        switch (e.KeyCode)
        {
            case Keys.Up:
                foreach (var usedCommand in list1)
                {
                    textBox1.Text = usedCommand;
                }
                break;
        }
    }

So I’m trying to get the text I’ve entered in textBox1 back to textBox1 with the arrow up key.
The text I enter in textBox1 will be shown in textBox2 (but this isn’t relevant here).

Thanks for all who want to help me, because I don’t know what I’m doing wrong :(.

Answer 1

I suggest using a Stack<T> – it will be easier to track.

You can then use something like this:

public Stack<string> Undo { get; set; } // needs to be initialized before use
private void button1_Click(object sender, EventArgs e)
{
            if (string.IsNullOrEmpty(textBox1.Text))
                return;

            Undo.Push(textBox1.Text);
}

private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
            if (e.KeyCode != Keys.Up)
                return;

            if (Undo.Count == 0)
                return;

            textBox2.Text = Undo.Pop();
}

if you want a redo option then you can have a redo stack as well.