摘自:http://www.cnblogs.com/risen/archive/2008/01/15/1039751.html
public partial class AlertForm : Form
{
/*
* 在类AlertForm定义的下方，
* 我们创建用于显示的字符串和其颜色的变量，
* 再定义几个Rectangle对象的变量用于放置标题、
* 提示内容以及可以拖动窗体的区域和关闭按钮的区域。
* 然后，我们需要保存窗体在浮动时的高度以便计算移动后的新高度，
* intervalValue变量用来确定窗体显示和隐藏的速度。
* 进行平台调用时我们需要提前定义好常量的值用来传递给函数，
* WM_NCLBUTTONDOWN和HT_CAPTION常量用于拖动窗体，
* 他们的值都保存在WinUser.h头文件中，
* 所对应的动态链接库名为：user32.dll。
* 我们用到的Win32API为：SendMessage、ReleaseCapture和ShowWindow，
* 通过使用DllImportAttribute可以导入相应的函数并在程序中重新进行定义，如下：
*/
public Bitmap BackgroundBitmap = null;
private string titleText;
private string contentText;
private Color normalTitleColor = Color.FromArgb(0, 0, 0);
private Font normalTitleFont = new Font("宋体", 12, FontStyle.Regular, GraphicsUnit.Pixel);
private Color normalContentColor = Color.FromArgb(0, 0, 0);
private Font normalContentFont = new Font("宋体", 12, FontStyle.Regular, GraphicsUnit.Pixel);
public Rectangle TitleRectangle;
public Rectangle TitlebarRectangle;
public Rectangle ContentRectangle;
public Rectangle CloseBtnRectangle;
private Rectangle WorkAreaRectangle;
private int SavedTop;
private int currentTop = 1;
private int intervalValue = 2;
public const int WM_NCLBUTTONDOWN = 0x00A1; //消息:左键点击 winuser.h
public const int HT_CAPTION = 0x0002; //标题栏
[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam); //发送消息 //winuser.h 中有函数原型定义
[DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture(); //释放鼠标捕捉 winuser.h
/*
* SendMessage向消息循环发送标题栏被按下的消息来模拟窗体的拖动，
* ShowWindow用来将特定句柄的窗体显示出来，
* 注意第二个参数nCmdShow，它表示窗体应该怎样显示出来，
* 而我们需要窗体不获得焦点显示出来，
* SW_SHOWNOACTIVATE可以满足我们要求，
* 继续在WinUser.h文件中搜索找到该常量对应的值为4，
* 于是我们就可以这样调用来显示窗体了：
*/
[DllImportAttribute("user32.dll")] //winuser.h
private static extern Boolean ShowWindow(IntPtr hWnd, Int32 nCmdShow);
public int CurrentState=0; //0=hide 1=uptoshow 2=showing 3=downtohide
private AlertForm()
{
InitializeComponent();
SetBackgroundBitmap(snnu.ccs.Properties.Resources.popup2, Color.FromArgb(255, 0, 255));
}
public static void Show(string ftitletext, string fcontenttext)
{
AlertForm alert = new AlertForm();
alert.ShowForm(ftitletext, fcontenttext);
}
/*
* 当窗体需要升起时将窗体的Top属性值不断减少，
* 而窗体回落时将Top属性值增加并超过屏幕的高度窗体就消失了，
* 虽然原理很简单但仍需精确控制。
* SetBackgroundBitmap函数首先将窗体背景图像保存到BackgroundBitmap变量中，
* 然后根据该位图图像轮廓和透明色创建Region，BitmapToRegion就用于完成Bitmap到Region的转换，
* 程序再将这个Region付值给窗体的Region属性以完成不规则窗体的创建。
*/
protected void SetBackgroundBitmap(Image image, Color transparencyColor)
{
BackgroundBitmap = new Bitmap(image);
Width = BackgroundBitmap.Width;
Height = BackgroundBitmap.Height;
TitleRectangle = new Rectangle(2, 1, 70, 25);
TitlebarRectangle = new Rectangle(1, 1, Width, 25);
ContentRectangle = new Rectangle(1, 25, Width, Height - 25);
CloseBtnRectangle = new Rectangle(Width - 25, 1, 25, 25);
Region = BitmapToRegion(BackgroundBitmap, transparencyColor);
}
protected Region BitmapToRegion(Bitmap bitmap, Color transparencyColor)
{
if (bitmap == null)
throw new ArgumentNullException("Bitmap", "Bitmap cannot be null!");
int height = bitmap.Height;
int width = bitmap.Width;
GraphicsPath path = new GraphicsPath();
for (int j = 0; j < height; j++)
for (int i = 0; i < width; i++)
{
if (bitmap.GetPixel(i, j) == transparencyColor)
continue;
int x0 = i;
while ((i < width) && (bitmap.GetPixel(i, j) != transparencyColor))
i++;
path.AddRectangle(new Rectangle(x0, j, i - x0, 1));
}
Region region = new Region(path);
path.Dispose();
return region;
}
protected void DrawText(Graphics grfx)
{
if (titleText != null && titleText.Length != 0)
{
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Near;
sf.LineAlignment = StringAlignment.Center;
sf.FormatFlags = StringFormatFlags.NoWrap;
sf.Trimming = StringTrimming.EllipsisCharacter;
grfx.DrawString(titleText, normalTitleFont, new SolidBrush(normalTitleColor), TitleRectangle, sf);
}
if (contentText != null && contentText.Length != 0)
{
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
sf.FormatFlags = StringFormatFlags.MeasureTrailingSpaces;
sf.Trimming = StringTrimming.Word;
grfx.DrawString(contentText, normalContentFont, new SolidBrush(normalContentColor), ContentRectangle, sf);
}
}
/*
* 通知窗体背景以及文字的绘制在重载的OnPaintBackground方法中完成，
* 而且利用了双重缓冲区技术来进行绘制操作，代码如下：
*/
protected override void OnPaintBackground(PaintEventArgs e)
{
Graphics grfx = e.Graphics;
grfx.PageUnit = GraphicsUnit.Pixel;
Graphics offScreenGraphics;
Bitmap offscreenBitmap;
offscreenBitmap = new Bitmap(BackgroundBitmap.Width, BackgroundBitmap.Height);
offScreenGraphics = Graphics.FromImage(offscreenBitmap);
if (BackgroundBitmap != null)
{
offScreenGraphics.DrawImage(BackgroundBitmap, 0, 0, BackgroundBitmap.Width, BackgroundBitmap.Height);
}
DrawText(offScreenGraphics);
grfx.DrawImage(offscreenBitmap, 0, 0);
}
/*
* CurrentState变量表示窗体的状态是显示中、停留中还是隐藏中，
* 两个计时器根据窗体不同状态对窗体的位置进行更改，
* 我们会使用SetBounds来执行该操作：
* this.SetBounds(WorkAreaRectangle.Width - this.Width, WorkAreaRectangle.Height - currentTop, this.Width, this.Height);
*/
protected void ShowForm(string ftitletext, string fcontenttext)
{
titleText = ftitletext;
contentText = fcontenttext;
WorkAreaRectangle = Screen.GetWorkingArea(WorkAreaRectangle);
this.Top = WorkAreaRectangle.Height + this.Height;
FormBorderStyle = FormBorderStyle.None;
WindowState = FormWindowState.Normal;
this.SetBounds(WorkAreaRectangle.Width - this.Width, WorkAreaRectangle.Height - currentTop, this.Width, this.Height);
CurrentState = 1;
timer1.Enabled = true;
ShowWindow(this.Handle, 4); //#define SW_SHOWNOACTIVATE 4
}
private void timer1_Tick(object sender, EventArgs e)
{
if (CurrentState == 1)
{
this.SetBounds(WorkAreaRectangle.Width - this.Width, WorkAreaRectangle.Height - currentTop, this.Width, this.Height);
currentTop = currentTop + intervalValue;
if (this.Top <= WorkAreaRectangle.Height - this.Height)
{
timer1.Enabled = false;
CurrentState = 2;
timer2.Enabled = true; //显示停留计时
currentTop = 1;
}
}
else if (CurrentState==3)
{
this.SetBounds(WorkAreaRectangle.Width - this.Width, SavedTop + currentTop, this.Width, this.Height);
currentTop = currentTop + intervalValue;
if (this.Top >= WorkAreaRectangle.Height)
{
timer1.Enabled = false;
this.Close();
CurrentState = 0;
currentTop = 1;
}
}
}
/*
上述代码首先返回窗体绘制表面的Graphics并保存在变量grfx中，
* 然后创建一个内存Graphics对象offScreenGraphics和内存位图对象offscreenBitmap，
* 将内存位图对象的引用付值给offScreenGraphics，
* 这样所有对offScreenGraphics的绘制操作也都同时作用于offscreenBitmap，
* 这时就将需要绘制到通知窗体表面的背景图像BackgroundBitmap绘制到内存的Graphics对象上，
* DrawText函数根据需要显示文字的大小和范围调用Graphics.DrawString将文字显示在窗体的特定区域。
* 最后，调用Graphics.DrawImage将内存中已经绘制完成的图像显示到通知窗体表面。
* 我们还需要捕获窗体的鼠标操作，有三个操作在这里进行，
* 1、处理拖动窗体操作，
* 2、处理通知窗体的关闭操作，
* 3、内容区域的单击操作。
* 三个操作都需要检测鼠标的当前位置与每个Rectangle区域的包含关系，
* 只要单击落在特定区域我们就进行相应的处理，代码如下
*/
private void TaskbarForm_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (TitlebarRectangle.Contains(e.Location)) //单击标题栏时拖动
{
ReleaseCapture(); //释放鼠标捕捉
SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0); //发送左键点击的消息至该窗体(标题栏)
}
if (CloseBtnRectangle.Contains(e.Location)) //单击Close按钮关闭
{
this.Close();
currentTop = 1;
}
}
}
private void timer2_Tick(object sender, EventArgs e)
{
timer2.Enabled = false;
CurrentState = 1;
currentTop = 1;
SavedTop = this.Top;
CurrentState = 3;
timer1.Enabled = true;
}
private void TaskbarForm_MouseMove(object sender, MouseEventArgs e)
{
if (ContentRectangle.Contains(e.Location))
{
Cursor = Cursors.Hand;
}
else
Cursor = Cursors.Default;
}
}