private void 打开图形文件ToolStripMenuItem_Click(object sender, EventArgs e)
 {
   string NameFile;
   if (this.openFileDialog1.ShowDialog() == DialogResult.OK)
   {
 NameFile = this.openFileDialog1.FileName;
 if (NameFile != "")
 {
   this.pictureBox1.Image = Image.FromFile(NameFile);
 }
   }
 }
private void 打开文本文件ToolStripMenuItem_Click(object sender, EventArgs e)
 {
   string Filename;
   pictureBox1.Visible = false;
   if (this.openFileDialog1.ShowDialog() == DialogResult.OK)
   {
 Filename = openFileDialog1.FileName;
 if (Filename != "")
 {
   this.textBox1.Text = Filename;
   this.richTextBox1.LoadFile(@Filename, RichTextBoxStreamType.PlainText);
 }
   }
 }

//构造函数
    this.textBox1.KeyPress += new KeyPressEventHandler(textBox1_KeyPress);
    this.textBox1.Validating += new CancelEventHandler(textBox1_Validating);
    this.richTextBox1.LinkClicked += new LinkClickedEventHandler(richTextBox1_LinkClicked);
 //取消或置为粗体
 private void button2_Click(object sender, System.EventArgs e)
 {
    Font oldFont = this.richTextBox1.SelectionFont;
    Font newFont;
    if (oldFont.Bold)
  newFont = new Font(oldFont,oldFont.Style & ~FontStyle.Bold);
    else
  newFont = new Font(oldFont,oldFont.Style | FontStyle.Bold);
    this.richTextBox1.SelectionFont = newFont;
    this.richTextBox1.Focus();
 }
 //取消或置为斜体
 private void button7_Click(object sender, System.EventArgs e)
 {
    Font oldFont = this.richTextBox1.SelectionFont;
    Font newFont;
    if (oldFont.Italic)
  newFont = new Font(oldFont,oldFont.Style & ~FontStyle.Italic);
    else
  newFont = new Font(oldFont,oldFont.Style | FontStyle.Italic);
    this.richTextBox1.SelectionFont = newFont;
    this.richTextBox1.Focus();
 }
 //取消或加上下划线
 private void button8_Click(object sender, System.EventArgs e)
 {
    Font oldFont = this.richTextBox1.SelectionFont;
    Font newFont;
    if (oldFont.Underline)
  newFont = new Font(oldFont,oldFont.Style & ~FontStyle.Underline);
    else
  newFont = new Font(oldFont,oldFont.Style | FontStyle.Underline);
    this.richTextBox1.SelectionFont = newFont;
    this.richTextBox1
  .Focus();
 }
 //取消或置为居中
 private void button5_Click(object sender, System.EventArgs e)
 {
    if (this.richTextBox1.SelectionAlignment == HorizontalAlignment.Center)
  this.richTextBox1.SelectionAlignment = HorizontalAlignment.Left;
    else
  this.richTextBox1.SelectionAlignment = HorizontalAlignment.Center;
    this.richTextBox1.Focus();
 }
 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
 {
    if((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8 && e.KeyChar !=13) 
    {
  e.Handled = true;
    }
    else if(e.KeyChar == 13) 
    {
  TextBox txt = (TextBox)sender;
  if(txt.Text.Length > 0) 
    ApplyTextSize(txt.Text);
  e.Handled = true;
  this.richTextBox1.Focus();
    }
 }
 private void textBox1_Validating(object sender, CancelEventArgs e)
 {
    TextBox txt = (TextBox)sender;
    ApplyTextSize(txt.Text);
    this.richTextBox1.Focus();
  }
 //改变字体大小
 private void ApplyTextSize(string textSize)
 {
    float newSize = Convert.ToSingle(textSize);
    FontFamily currentFontFamily;
    Font newFont;
    currentFontFamily = this.richTextBox1.SelectionFont.FontFamily;
    newFont = new Font(currentFontFamily, newSize);
    this.richTextBox1.SelectionFont = newFont;
 }
 //打开网页
 private void richTextBox1_LinkClicked(object sender, LinkClickedEventArgs e)
 {
    System.Diagnostics.Process.Start(e.LinkText);
 }
 //打开文件
 private void button1_Click(object sender, System.EventArgs e)
 {
    try
    {
  this.richTextBox1.LoadFile(@"..\..\test.txt");
    }
    catch(System.IO.FileNotFoundException)
    {
  MessageBox.Show("File not found!");
    }
 }
 //保存文件
 private void button6_Click(object sender, System.EventArgs e)
 {
    try
    {
  this.richTextBox1.SaveFile(@"..\..\test.txt");
    }
    catch(System.Exception err)
    {
  MessageBox.Show(err.Message);
    }
 }

public int Find(char[]);

private void button1_Click(object sender, System.EventArgs e)
{
   MessageBox.Show(FindMyText(new char[]{'D','e','l','t','a'}).ToString());
}
public int FindMyText(char[] text)
{
   // Initialize the return value to false by default.
   int returnValue = -1;
   // Ensure that a search string has been specified and a valid start point.
   if (text.Length > 0) 
   {
     // Obtain the location of the first character found in the control
     // that matches any of the characters in the char array.
     int indexToText = richTextBox1.Find(text);
     // Determine whether the text was found in richTextBox1.
     if(indexToText >= 0)
     {
       // Return the location of the character.
       returnValue = indexToText;
     }
   }
   return returnValue;
}

public int Find(string);

 public int Find(char[], int);

 public int Find(string, RichTextBoxFinds);

public bool FindMyText(string text)
{
  // Initialize the return value to false by default.
  bool returnValue = false;
  // Ensure a search string has been specified.
  if (text.Length > 0) 
  {
    // Obtain the location of the search string in richTextBox1.
    int indexToText = richTextBox1.Find(text, RichTextBoxFinds.MatchCase);
    // Determine if the text was found in richTextBox1.
    if(indexToText >= 0)
    {
     returnValue = true;
    }
  }
  return returnValue;
}

public int Find(char[], int, int);

 public int Find(string, int, RichTextBoxFinds);