C#Winform实现简单的虚拟键盘

关键技术点有两个：

1.将键盘所在的窗体设置为浮动工具条窗体。只要将窗体的CreateParams重写即可，这样窗体就不会获取焦点，代码如下：

#region 将当前窗体指定为浮动工具条窗体
public enum WindowStyles : uint
{
WS_OVERLAPPED = 0x00000000,
WS_POPUP = 0x80000000,
WS_CHILD = 0x40000000,
WS_MINIMIZE = 0x20000000,
WS_VISIBLE = 0x10000000,
WS_DISABLED = 0x08000000,
WS_CLIPSIBLINGS = 0x04000000,
WS_CLIPCHILDREN = 0x02000000,
WS_MAXIMIZE = 0x01000000,
WS_BORDER = 0x00800000,
WS_DLGFRAME = 0x00400000,
WS_VSCROLL = 0x00200000,
WS_HSCROLL = 0x00100000,
WS_SYSMENU = 0x00080000,
WS_THICKFRAME = 0x00040000,
WS_GROUP = 0x00020000,
WS_TABSTOP = 0x00010000,

WS_MINIMIZEBOX = 0x00020000,
WS_MAXIMIZEBOX = 0x00010000,

WS_CAPTION = WS_BORDER | WS_DLGFRAME,
WS_TILED = WS_OVERLAPPED,
WS_ICONIC = WS_MINIMIZE,
WS_SIZEBOX = WS_THICKFRAME,
WS_TILEDWINDOW = WS_OVERLAPPEDWINDOW,

WS_OVERLAPPEDWINDOW = WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX,
WS_POPUPWINDOW = WS_POPUP | WS_BORDER | WS_SYSMENU,
WS_CHILDWINDOW = WS_CHILD,

//Extended Window Styles

WS_EX_DLGMODALFRAME = 0x00000001,
WS_EX_NOPARENTNOTIFY = 0x00000004,
WS_EX_TOPMOST = 0x00000008,
WS_EX_ACCEPTFILES = 0x00000010,
WS_EX_TRANSPARENT = 0x00000020,

//#if(WINVER >= 0x0400)

WS_EX_MDICHILD = 0x00000040,
WS_EX_TOOLWINDOW = 0x00000080,
WS_EX_WINDOWEDGE = 0x00000100,
WS_EX_CLIENTEDGE = 0x00000200,
WS_EX_CONTEXTHELP = 0x00000400,

WS_EX_RIGHT = 0x00001000,
WS_EX_LEFT = 0x00000000,
WS_EX_RTLREADING = 0x00002000,
WS_EX_LTRREADING = 0x00000000,
WS_EX_LEFTSCROLLBAR = 0x00004000,
WS_EX_RIGHTSCROLLBAR = 0x00000000,

WS_EX_CONTROLPARENT = 0x00010000,
WS_EX_STATICEDGE = 0x00020000,
WS_EX_APPWINDOW = 0x00040000,

WS_EX_OVERLAPPEDWINDOW = (WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE),
WS_EX_PALETTEWINDOW = (WS_EX_WINDOWEDGE | WS_EX_TOOLWINDOW | WS_EX_TOPMOST),

//#endif /* WINVER >= 0x0400 */

//#if(WIN32WINNT >= 0x0500)

WS_EX_LAYERED = 0x00080000,

//#endif /* WIN32WINNT >= 0x0500 */

//#if(WINVER >= 0x0500)

WS_EX_NOINHERITLAYOUT = 0x00100000, // Disable inheritence of mirroring by children
WS_EX_LAYOUTRTL = 0x00400000, // Right to left mirroring

//#endif /* WINVER >= 0x0500 */

//#if(WIN32WINNT >= 0x0500)

WS_EX_COMPOSITED = 0x02000000,
WS_EX_NOACTIVATE = 0x08000000

//#endif /* WIN32WINNT >= 0x0500 */

}
protected override CreateParams CreateParams
{
get
{
CreateParams ret = base.CreateParams;
ret.Style = (int)WindowStyles.WS_THICKFRAME | (int)WindowStyles.WS_CHILD;
ret.ExStyle |= (int)WindowStyles.WS_EX_NOACTIVATE | (int)WindowStyles.WS_EX_TOOLWINDOW;
ret.X = this.Location.X;
ret.Y = this.Location.Y;
return ret;
}
}

#endregion

2. 使用SendKeys方法，将按键发送给应用程序。可参考SendKeys的使用方法。