用户可以选择想要操作的菜单项，但由于菜单项没有制作相应的操作，所以，鼠标点击时没有任何反应。本书的范例1-2将详细讲解如何触发菜单的相应事件。

private void miOpen_Click(object sender, EventArgs e)
{
    OpenFileDialog dlgOpen = new OpenFileDialog();
    dlgOpen.Filter = "文本文件(*.txt)|*.txt";
    if (dlgOpen.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.LoadFile(dlgOpen.FileName,RichTextBoxStreamType
      .PlainText);
    }
  }

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    //打开文件对话框
    OpenFileDialog ofd = new OpenFileDialog();
    //对话框标题
    ofd.Title = "打开文件";
    //设置打开文件类型
    ofd.Filter = "TextDocument(*.rtf)|*.rtf";
    if (ofd.ShowDialog() == DialogResult.OK)
    {
      //文本框显示文件内容
      this.rchShow.LoadFile(ofd.FileName,
      RichTextBoxStreamType.PlainText);
      this.Text = ofd.FileName;
    }
  }
  catch(IOException ex)
  {
    MessageBox.Show(ex.Message);
  }
}

private void miBold_Click(object sender, EventArgs e)
{
    Font oldFont=this.rchShow.SelectionFont;
    Font newFont;
    if (oldFont.Bold)
    {
      newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Bold);
    }
    else
    {
      newFont = new Font(oldFont,oldFont.Style|FontStyle.Bold);
    }
    this.rchShow.SelectionFont = newFont;
}

private void miItalic_Click(object sender, EventArgs e)
 {
    Font oldFont = this.rchShow.SelectionFont;
    Font newFont;
    if (oldFont.Italic)
    {
      newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Italic);
    }
    else
    {
      newFont = new Font(oldFont, oldFont.Style | FontStyle.Italic);
    }
      this.rchShow.SelectionFont = newFont;
    }

private void miUnderline_Click(object sender, EventArgs e)
{
  Font oldFont = this.rchShow.SelectionFont;
  Font newFont;
  if (oldFont.Underline)
  {
    newFont = new Font(oldFont, oldFont.Style &~FontStyle.Underline);
  }
  else
  {
    newFont = new Font(oldFont, oldFont.Style | FontStyle.Underline);
  }
  this.rchShow.SelectionFont = newFont;
}

private void miExit_Click(object sender, EventArgs e)
{
  Application.Exit();
}

public frmContainer()
{
  InitializeComponent();
  //显示孩子窗口
  frmEditor child = new frmEditor(this);
  child.Show();
}

public frmEditor(frmContainer parent)
{
  InitializeComponent();
  //设置子窗口的父窗口
  this.MdiParent = parent;
}

设置为MatchOnly的菜单项不能在菜单之间移动，但对于&File，两个菜单项的文本匹配，它们的菜单项是可以合并的。【File】菜单项是根据MergeIndex属性进行合并的。MergeIndex为MatchOnly的菜单项原地不动，其他菜单项的MergeIndex属性为“Insert”。

private int count;

public frmContainer()
{
    InitializeComponent();
    count = 1;
    frmChild newChild = new frmChild(this, count);
    newChild.Show();
}

private void miNew_Click(object sender, EventArgs e)
{
    frmChild newChild = new frmChild(this,++count);
    newChild.Show();
}

public frmChild(frmContainer parent,int count)
{
    InitializeComponent();
    this.MdiParent = parent;
    this.Text = "子窗口" + count.ToString();
}

private void miShowHelp_CheckedChanged(object sender, EventArgs e)
 {
  //参数sender传入的参数设置为ToolStripMenuItem控件
  ToolStripMenuItem mi = sender as ToolStripMenuItem;
  miHelp.Visible = mi.Checked;
 }

private void miShow_CheckedChanged(object sender, EventArgs e)
{
  ToolStripMenuItem tsmi = sender as ToolStripMenuItem;
  this.miHelp.Visible = tsmi.Checked;
}

1.应将窗体标题栏中的文字设置为有意义的文字，而且不是所有窗体都有标题栏的。

2.标题文字可以按以下几种情况命名。

（1）程序的名称：当窗体唯一时，可以用此种命名方式。

（2）窗口的目的：最常见的命名方式。

（3）窗体的名称：不要只用窗体的名称，而应该将其转换为具有意义的名称。

Form newform;

private void btnOpen_Click(object sender, EventArgs e)
{
    newform= new Form();
    newform.MaximizeBox = false;
    newform.MinimizeBox = false;
    //显示窗体
    newform.Show();
    this.btnClose.Enabled = true;
    this.btnOpen.Enabled = false;
}

private void btnClose_Click(object sender, EventArgs e)
{
    this.Close();
    this.btnClose.Enabled = false;
    this.btnOpen.Enabled = true;
}

private void btnOpenDialog_Click(object sender, EventArgs e)
{
  newform = new Form();
  newform.MaximizeBox = false;
  newform.MinimizeBox = false;
  //显示窗口
  newform.ShowDialog();
  this.btnCloseDialog.Enabled = true;
  this.btnOpenDialog.Enabled = false;
}

private void btnCloseDialog_Click(object sender, EventArgs e)
{
  this.Close();
  this.btnCloseDialog.Enabled = false;
  this.btnOpenDialog.Enabled = true;
}

用户显示窗体有两种形式：模式窗体和无模式窗体。无模式窗体不会使其他窗体无法使用（无模式窗体的显示代码为Show()方法）。无模式窗体的典型例子就是Word中的“查找和替换”窗口。当此窗口可见时，仍然可以操作其他窗口。模式窗口则相反，它处于显示状态时，其他应用窗体都不可以使用，除非模式窗体关闭（模式窗体的显示代码为ShowDialog()方法）。模式窗体的常用应用是对话框，如Word的打印对话框。

Form newform= new Form();
public Form1()
{
  InitializeComponent();
  this.btnShow.Enabled = true;
  this.btnUnShow.Enabled = false;
}

private void btnShow_Click(object sender, EventArgs e)
{
  //显示窗体
  newform.Visible = true;
  this.btnUnShow.Enabled = true;
  this.btnShow.Enabled = false;
}

private void btnUnShow_Click(object sender, EventArgs e)
{
  //隐藏窗体
  newform.Visible = false;
  this.btnShow.Enabled = true;
  this.btnUnShow.Enabled = false;
}

此窗体“消失”有两种方式：第一种是隐藏，这时窗体不关闭也不释放资源，只是用户不可见。实现窗体隐藏的代码是Visible属性为“false”。被隐藏的窗体仍然驻留在内存中，并且窗体中的所有控件和变量都保持其值，当需要再次显示窗体时，只要Visible属性为“true”即可。第二种是卸载，这时窗体被关闭并释放所占资源，用户同样不可见。实现窗体卸载的代码是Close()方法。

private void btnGet_Click(object sender, EventArgs e)
{
  this.lblWidth.Text = Screen.PrimaryScreen.WorkingArea.Width.ToString();
  this.lblHeight.Text = Screen.PrimaryScreen.WorkingArea.Height.ToString();
}

private void Form1_Load(object sender, EventArgs e)
{
  //产生一个随机数
  Random random = new Random();
  int i = random.Next(imageList1.Images.Count);
  this.BackgroundImage=imageList1.Images[i];
}

private int startX;
private int startY;

private void btnDraw_MouseDown(object sender, MouseEventArgs e)
{
    //如果按的是鼠标左键
    if (e.Button == MouseButtons.Left)
    {
      //获得鼠标在产生事件时的x坐标
      startX = e.X;
      //获得鼠标在产生事件时的y坐标
      startY = e.Y;
    }
}

private void btnDraw_MouseMove(object sender, MouseEventArgs e)
{
    //如果单击鼠标左键
    if (e.Button == MouseButtons.Left)
    {
      //窗体的左边缘重新定位
        this.Left += e.X - startX;
      //窗体的上边缘重新定位
        this.Top += e.Y - startY;
    }
 }

private void tt_Draw(object sender, DrawToolTipEventArgs e)
{
  //使用系统颜色绘制提示字的背景色
  e.DrawBackground();
 //使用系统边框颜色绘制提示字的边框
  e.DrawBorder();
  using (StringFormat sf = new StringFormat())
  {
    //文本的垂直对齐
    sf.Alignment = StringAlignment.Center;
   //文本的水平对齐
   sf.LineAlignment = StringAlignment.Center;
   sf.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.None;
   sf.FormatFlags = StringFormatFlags.NoWrap;
   using (Font f = new Font("宋体", 9))
   {
      //绘制提示字
      e.Graphics.DrawString(e.ToolTipText, f, SystemBrushes.
      ActiveCaptionText, e.Bounds, sf);
    }
  }
}

//设置计数器的计数函数
private void timer1_Tick(object sender, EventArgs e)
{
    this.Opacity += 0.1;
}

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
  if(MessageBox.Show("确认要关闭此窗体吗?","确认对话",MessageBoxButtons.YesNo)
    ==DialogResult.Yes)
  {
    e.Cancel=false;
  }
  else
  {
    e.Cancel=true;
  }
}

private void timer1_Tick(object sender, EventArgs e)
{
  this.lblWord.Top -= 10;
  if (this.lblWord.Bottom < 0)
  {
    this.lblWord.Top = this.Height;
  }
}

private void btnBegin_Click(object sender, EventArgs e)
{
  timer1.Enabled = true;
}

private void btnStop_Click(object sender, EventArgs e)
{
  timer1.Enabled = false;
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (this.dlgOpen.ShowDialog() == DialogResult.OK)
    {
        this.rchShow.LoadFile(this.dlgOpen.FileName,
        RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
      MessageBox.Show(ex.Message);
  }
}

private void miPS_Click(object sender, EventArgs e)
{
    this.dlgPS.ShowDialog();
}

private void pd_PrintPage(object sender, PrintPageEventArgs e)
{
    int x = e.MarginBounds.Left;
    int y = e.MarginBounds.Top;
    lines = this.rchShow.Text.Split(param);
    while (linesPrinted < lines.Length)
    {
          e.Graphics.DrawString(lines[linesPrinted++],
          new Font("Arial", 10), Brushes.Black, x, y);
          y += 15;
          if (y >= e.PageBounds.Height -80)
          {
              e.HasMorePages = true;
              return;
            }
        }
        linesPrinted = 0;
        e.HasMorePages = false;
      }

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (this.dlgOpen.ShowDialog() == DialogResult.OK)
    {
        this.rchShow.LoadFile(this.dlgOpen.FileName,
        RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
}

private void miPp_Click(object sender, EventArgs e)
{
    this.dlgpp.ShowDialog();
}

char[] param ={ '\n' };
private string[] lines;
private int linesPrinted;
private void pd_PrintPage(object sender, PrintPageEventArgs e)
{
  int x = e.MarginBounds.Left;
  int y = e.MarginBounds.Top;
    lines = this.rchShow.Text.Split(param);
    while (linesPrinted < lines.Length)
      {
        e.Graphics.DrawString(lines[linesPrinted++], new Font("Arial", 10),
            Brushes.Black, x, y);
    y += 15;
    if (y >= e.PageBounds.Height -80)
      {
      e.HasMorePages = true;
      return;
      }
  }
    linesPrinted = 0;
    e.HasMorePages = false;
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (this.dlgOpen.ShowDialog() == DialogResult.OK)
    {
          this.rchShow.LoadFile(this.dlgOpen.FileName,
          RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
      MessageBox.Show(ex.Message);
  }
}

char[] param ={ '\n' };
private string[] lines;
private int linesPrinted;
private void pd_PrintPage(object sender, PrintPageEventArgs e)
{
  int x = e.MarginBounds.Left;
    int y = e.MarginBounds.Top;
      lines = this.rchShow.Text.Split(param);
      while (linesPrinted < lines.Length)
      {
          e.Graphics.DrawString(lines[linesPrinted++],
              new Font("Arial", 10), Brushes.Black, x, y);
    y += 15;
    if (y >= e.PageBounds.Height -80)
      {
      e.HasMorePages = true;
      return;
      }
 }
 linesPrinted = 0;
 e.HasMorePages = false;

private void miPrint_Click(object sender, EventArgs e)
{
    try
    {
        if (this.dlgprint.ShowDialog() == DialogResult.OK)
        {
            pd.Print();
        }
    }
    catch (InvalidPrinterException ex)
    {
        MessageBox.Show(ex.Message);
    }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    //判断是否选择了文件
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {//将文件加载到RichTextBox中
      this.rchShow.LoadFile(dlgOpenFile.FileName,
      RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
 }

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    //判断是否选择了文件
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {//将文件加载到RichTextBox中
    this.rchShow.LoadFile(dlgOpenFile.FileName,
    RichTextBoxStreamType.PlainText);
  }
}
catch (Exception ex)
{
  MessageBox.Show(ex.Message);
}
}

private void miMultiSel_Click(object sender, EventArgs e)
{
  try
  {
      if (this.dglOpen.ShowDialog() == DialogResult.OK)
      {
        StringBuilder sb=new StringBuilder();
        foreach (string s in this.dglOpen.FileNames)
        {
            sb.Append(File.ReadAllText(s)).AppendLine();
        }
        if (sb.Length > 0)
        {
            this.rchShow.Text = sb.ToString();
        }
      }
  }
  catch (Exception ex)
  {
      MessageBox.Show(ex.Message);
  }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.LoadFile(dlgOpenFile.FileName,
      RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
 }

private void miClose_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgSaveFile.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.SaveFile(dlgSaveFile.FileName,
      RichTextBoxStreamType.PlainText);
     }
  }
  catch (Exception ex)
  {
     MessageBox.Show(ex.Message);
  }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.LoadFile(dlgOpenFile.FileName,
      RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
 }

private void miClose_Click(object sender, EventArgs e)
{
 try
 {
  if (dlgSaveFile.ShowDialog() == DialogResult.OK)
  {
    this.rchShow.SaveFile(dlgSaveFile.FileName,
    RichTextBoxStreamType.PlainText);
    }
 }
 catch (Exception ex)
 {
    MessageBox.Show(ex.Message);
 }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (this.dlgFB.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.Text = "选择的文件夹名为：" + this.dlgFB.SelectedPath;
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
      if (this.dlgFB.ShowDialog() == DialogResult.OK)
      {
      this.rchShow.Text="选择的文件夹名为："+this.dlgFB.SelectedPath;
      }
  }
  catch (Exception ex)
  {
      MessageBox.Show(ex.Message);
  }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.LoadFile(dlgOpenFile.FileName,
      RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
 }

private void miFont_Click(object sender, EventArgs e)
{
  if (dlgFont.ShowDialog() == DialogResult.OK)
  {
    this.rchShow.Font = dlgFont.Font;
  }
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgOpenFile.ShowDialog() == DialogResult.OK)
    {
      this.rchShow.LoadFile(dlgOpenFile.FileName,
      RichTextBoxStreamType.PlainText);
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
 }

private void miFont_Click(object sender, EventArgs e)
{
  try
  {
    if(dlgColor.ShowDialog()==DialogResult.OK)
    {
      this.rchShow.SelectionColor = dlgColor.Color;
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
   }
 }

public frmChild(frmParent parent)
{
 InitializeComponent();
 this.MdiParent = parent;
}

public frmParent()
{
  InitializeComponent();
  frmChild child = new frmChild(this);
  child.Show();
}

1.Windows一般可以编写3种应用程序

基于对话框的应用程序—给用户提供一个对话框，该对话框提供了用户所需要的功能，如字体对话框、颜色对话框。

单一文档界面（SDI）—给用户提供一个菜单、一个或多个工具栏和一个窗口，用户可以执行功能，如写字板。

多文档界面（MDI）—给用户提供一个菜单、一个或多个工具栏和多个窗口，用户可以执行功能，如Word应用程序。

2.MDI应用程序的相关知识

MDI应用程序至少由两个窗口组成：一个窗口叫MDI容器（Container），另一个窗口叫MDI子窗口。一个MDI容器可以放置多个MDI子窗口，实现多文档状态。

public frmContainer()
{
    InitializeComponent();
    frmEditor child = new frmEditor(this);
    child.Show();
}

public frmEditor(frmContainer parent)
{
  InitializeComponent();
  this.MdiParent = parent;
}

private void miNew_Click(object sender, EventArgs e)
{
  this.rchtxtShow.Clear();
}

private void miOpen_Click(object sender, EventArgs e)
{
  try
  {
    if (dlgOpen.ShowDialog() == DialogResult.OK)
    {
      if (dlgOpen.FilterIndex == 1)
      {
      this.rchtxtShow.LoadFile(dlgOpen.FileName,
      RichTextBoxStreamType.RichText);
      }
    }
  }
  catch(Exception ex)
  {
     MessageBox.Show(ex.Message);
  }
}

private void miSave_Click(object sender, EventArgs e)
{
 try
 {
  if (dlgSave.ShowDialog() == DialogResult.OK)
  {
    if (dlgSave.FilterIndex == 1)
    {
      this.rchtxtShow.SaveFile(dlgSave.FileName,
      RichTextBoxStreamType.RichText);
    }
    }
  }
  catch(Exception ex)
  {
      MessageBox.Show(ex.Message);
  }
 }

private void miClose_Click(object sender, EventArgs e)
{
    this.Close();
    }

private void miBold_Click(object sender, EventArgs e)
{
 Font oldFont = this.rchtxtShow.SelectionFont;
 Font newFont;
 if (oldFont.Bold)
 {
  newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Bold);
 }
 else
 {
  newFont = new Font(oldFont, oldFont.Style | FontStyle.Bold);
 }
 this.rchtxtShow.SelectionFont = newFont;
}

private void miItalic_Click(object sender, EventArgs e)
{
    Font oldFont = this.rchtxtShow.SelectionFont;
    Font newFont;
    if (oldFont.Italic)
    {
      newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Italic);
    }
    else
    {
      newFont = new Font(oldFont, oldFont.Style | FontStyle.Italic);
    }
    this.rchtxtShow.SelectionFont = newFont;
  }

private void miUnderline_Click(object sender, EventArgs e)
{
  Font oldFont = this.rchtxtShow.SelectionFont;
  Font newFont;
  if (oldFont.Underline)
  {
  newFont = new Font(oldFont, oldFont.Style & ~FontStyle.Underline);
  }
  else
  {
    newFont = new Font(oldFont, oldFont.Style | FontStyle.Underline);
  }
  this.rchtxtShow.SelectionFont = newFont;
}