最近公司做一个考试系统，需要一个答题栏，要求：占用屏幕上方一部分区域，而且始终置顶，当其他窗口最大化时“答题栏”始终置前并且不遮挡最大化窗口的任何部分！就像windows任务栏一样。
最终效果图如下：
首先，我们必须声明所需的结构和常量。
我们声明RECT WINAPI结构如下：
[StructLayout(LayoutKind.Sequential)]
struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
我们声明APPBARDATA SHELLAPI结构如下：
[StructLayout(LayoutKind.Sequential)]
struct APPBARDATA
{
public int cbSize;
public IntPtr hWnd;
public int uCallbackMessage;
public int uEdge;
public RECT rc;
public IntPtr lParam;
}
然后，我们声明AppBar用到的常量如下：
enum ABMsg : int
{
ABM_NEW=0,
ABM_REMOVE,
ABM_QUERYPOS,
ABM_SETPOS,
ABM_GETSTATE,
ABM_GETTASKBARPOS,
ABM_ACTIVATE,
ABM_GETAUTOHIDEBAR,
ABM_SETAUTOHIDEBAR,
ABM_WINDOWPOSCHANGED,
ABM_SETSTATE
}
enum ABNotify : int
{
ABN_STATECHANGE=0,
ABN_POSCHANGED,
ABN_FULLSCREENAPP,
ABN_WINDOWARRANGE
}
enum ABEdge : int
{
ABE_LEFT=0,
ABE_TOP,
ABE_RIGHT,
ABE_BOTTOM
}
接下来，我们声明需要用到的WIN32和SHELL API接口：
[DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);
[DllImport("USER32")]
static extern int GetSystemMetrics(int Index);
[DllImport("User32.dll", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Auto)]
static extern bool MoveWindow(IntPtr hWnd, int x, int y, int cx, int cy, bool repaint);
[DllImport("User32.dll", CharSet = CharSet.Auto)]
static extern int RegisterWindowMessage(string msg);
下一步，我们创建一个注册AppBar的方法。
private void RegisterBar()
{
APPBARDATA abd = new APPBARDATA();
abd.cbSize = Marshal.SizeOf(abd);
abd.hWnd = this.Handle;
if (!fBarRegistered)
{
uCallBack = RegisterWindowMessage("AppBarMessage");
abd.uCallbackMessage = uCallBack; uint ret = SHAppBarMessage((int)ABMsg.ABM_NEW, ref abd);
fBarRegistered = true; ABSetPos();
}
else
{
SHAppBarMessage((int)ABMsg.ABM_REMOVE, ref abd);
fBarRegistered = false;
}
}
最后，我们创建一个设置AppBar位置的方法。
private void ABSetPos()
{
APPBARDATA abd = new APPBARDATA();
abd.cbSize = Marshal.SizeOf(abd);
abd.hWnd = this.Handle;
abd.uEdge = (int)ABEdge.ABE_TOP; if (abd.uEdge == (int)ABEdge.ABE_LEFT || abd.uEdge == (int)ABEdge.ABE_RIGHT)
{
abd.rc.top = 0;
abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
if (abd.uEdge == (int)ABEdge.ABE_LEFT)
{
abd.rc.left = 0;
abd.rc.right = Size.Width;
}
else
{
abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
abd.rc.left = abd.rc.right - Size.Width;
} }
else
{
abd.rc.left = 0;
abd.rc.right = SystemInformation.PrimaryMonitorSize.Width;
if (abd.uEdge == (int)ABEdge.ABE_TOP)
{
abd.rc.top = 0;
abd.rc.bottom = Size.Height;
}
else
{
abd.rc.bottom = SystemInformation.PrimaryMonitorSize.Height;
abd.rc.top = abd.rc.bottom - Size.Height;
}
} // Query the system for an approved size and position.
SHAppBarMessage((int)ABMsg.ABM_QUERYPOS, ref abd); // Adjust the rectangle, depending on the edge to which the
// appbar is anchored.
switch (abd.uEdge)
{
case (int)ABEdge.ABE_LEFT:
abd.rc.right = abd.rc.left + Size.Width;
break;
case (int)ABEdge.ABE_RIGHT:
abd.rc.left = abd.rc.right - Size.Width;
break;
case (int)ABEdge.ABE_TOP:
abd.rc.bottom = abd.rc.top + Size.Height;
break;
case (int)ABEdge.ABE_BOTTOM:
abd.rc.top = abd.rc.bottom - Size.Height;
break;
} // Pass the final bounding rectangle to the system.
SHAppBarMessage((int)ABMsg.ABM_SETPOS, ref abd); // Move and size the appbar so that it conforms to the
// bounding rectangle passed to the system.
MoveWindow(abd.hWnd, abd.rc.left, abd.rc.top,
abd.rc.right - abd.rc.left, abd.rc.bottom - abd.rc.top, true);
}
参考地址：http://www.codeproject.com/Articles/6741/AppBar-using-C
下载地址：http://pan.baidu.com/s/1qY4HX2c b7nv
