How to Undo and Redo in C# (Rich Text Box)

c#, visual-studio-2012, winforms

Solution

Ok, I'll post some code to help you get started. first you need to listen for the `TextChanged` event.

textBox1.TextChanged += new EventHandler(textBox1_TextChanged);

and you need to declare a stack in the class

 Stack<string> undoList = new Stack<string>();

In the text changed handler, you need to add the contents of the textbox to the stack

 void textBox1_TextChanged(object sender, EventArgs e)
    {
        undoList.Push(textBox1.Text);
    }

Then you need to handle the undo, so you could simply use CTRL-Z

 textBox1.KeyDown += new KeyEventHandler(textBox1_KeyDown);

void textBox1_KeyDown(object sender, KeyEventArgs e)
    {
         if(e.KeyCode == Keys.Z && (e.Control)) {
             textBox1.Text = undoList.Pop();
         }
    }

Problem

I've been trying to get undo and redo working in my text editor for about 3 days now. It's doing my head in. I have a text box (named `richTextBoxPrintCtrl1`), which I would like to be able to undo and *redo *(word by word). So if I click the undo button, it undoes the last word. And if I then clicked the redo button, it redoes the last word. Could somebody help me get this working? `richTextBoxPrintCtrl1.Undo();` doesn't work very well. It deletes everything typed in the text box. Thanks in advance for your help. I know this question has been asked many times before, but I can't get it working using the information from the questions I've browsed here on SO.

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