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    <p>This is a very basic idea, and I'm sure that many improvements could be made.</p> <p>I would create a <code>String Array</code> and incrementally store the value of the <code>RichTextBox</code> (In the <code>TextChanged</code> event, under your own conditions) in the array. As you store the value, increment the value of a counter, say <code>stackcount</code>. When the user undoes, decrement the <code>stackcount</code> and set the <code>RichTextBox.Text = array(stackcount)</code>. If they redo, then increment the value of the counter and set the value again. If they undo and then change the text, then clear all values onwards.</p> <p>I am sure that many other people may have better suggestions/changes for this, so please post in comments and I will update, or edit it yourself!</p> <p><strong>Example in C#</strong></p> <pre><code>using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace RedoUndoApp { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public string[] RTBRedoUndo; public int StackCount = 0; public int OldLength = 0; public int ChangeToSave = 5; public bool IsRedoUndo = false; private void Form1_Load(object sender, EventArgs e) { RTBRedoUndo = new string[10000]; RTBRedoUndo[0] = ""; } private void undo_Click(object sender, EventArgs e) { IsRedoUndo = true; if (StackCount &gt; 0 &amp;&amp; RTBRedoUndo[StackCount - 1] != null) { StackCount = StackCount - 1; richTextBox1.Text = RTBRedoUndo[StackCount]; } } private void redo_Click(object sender, EventArgs e) { IsRedoUndo = true; if (StackCount &gt; 0 &amp;&amp; RTBRedoUndo[StackCount + 1] != null) { StackCount = StackCount + 1; richTextBox1.Text = RTBRedoUndo[StackCount]; } } private void richTextBox1_TextChanged(object sender, EventArgs e) { if (IsRedoUndo == false &amp;&amp; richTextBox1.Text.Substring(richTextBox1.Text.Length - 1, 1) == " ")//(Math.Abs(richTextBox1.Text.Length - OldLength) &gt;= ChangeToSave &amp;&amp; IsRedoUndo == false) { StackCount = StackCount + 1; RTBRedoUndo[StackCount] = richTextBox1.Text; OldLength = richTextBox1.Text.Length; } } private void undo_MouseUp(object sender, MouseEventArgs e) { IsRedoUndo = false; } private void redo_MouseUp(object sender, MouseEventArgs e) { IsRedoUndo = false; } } } </code></pre>
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    1. POHow can I implement effective Undo/Redo into my WinForms application?
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    1. POHow can I implement effective Undo/Redo into my WinForms application?
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    1. COI had to convert it to C#. I've never done VB. But it didn't go too well, unfortunately. I'm going to try another method: http://www.codeproject.com/Articles/6947/Implementing-Object-Undo-and-Redo-capabilities-in
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    2. COThanks. But I'm getting some errors. Could you help me decipher them?
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    3. COif (RTBRedoUndo[StackCount - 1 != null]) error: Cannot implicitly convert type 'bool' to 'int'
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