CSharp扩展TrackBar控件显示不同风格.doc

C# 扩展TrackBar控件显示不同风格. 控件效果. 开发思路TrackBar控件没有像其他控件那样，直接提供给用户重绘的函数，要实现个性化的TrackBar控件直接继承TrackBar控件，利用TrackBar的一些Windows消息，获取TrackBar控件的信息，然后自己完全重绘，这种方法的好处是保留TrackBar控件的标准操作和属性，但是需要比较清楚的了解TrackBar控件的Windows消息。. 源码介绍实现TrackBar控件显示不同风格需要的一些API消息。TrackBar控件相关的一些消息都是以TBM(TackBar Message)开头的,在TrackBar控件的美化中，主要用到了以下三个消息：l TBM_GETCHANNELRECT 获取轨道的位置和大小。l TBM_GETTHUMBRECT 获取滑块的位置和大小。l TBM_GETNUMTICS 获取刻度的总个数。要获取这些信息，只需要向TrackBar控件发送相应的消息即可，例如需要获取取轨道的位置和大小：SendMessage(hWnd, TBM.TBM_GETCHANNELRECT, 0, ref trackRect)。接下来就是重绘TrackBar控件了。重绘TrackBar控件，需要重写WndProc函数，在WM_PAINT消息实现重绘就行了： / / 接收消息 / / protected override void WndProc(ref Message m) switch (m.Msg) case WM.WM_PAINT: if (!_bPainting) _bPainting = true; PAINTSTRUCT ps = new PAINTSTRUCT(); NativeMethods.BeginPaint(m.HWnd, ref ps); DrawTrackBar(m.HWnd); NativeMethods.ValidateRect(m.HWnd, ref ps.rcPaint); NativeMethods.EndPaint(m.HWnd, ref ps); _bPainting = false; m.Result = Result.TRUE; else base.WndProc(ref m); break; default: base.WndProc(ref m); break; DrawTrackBar函数的功能就是获取TrackBar控件的一些信息，然后分别调用四个函数来绘制TrackBar控件： OnRenderBackground函数，绘制TrackBar控件的背景。 OnRenderTick函数，绘制TrackBar控件的刻度。 OnRenderTrack函数，绘制TrackBar控件的轨道。 OnRenderThumb函数，绘制TrackBar控件的滑块。这四个函数都是可以重写的，如果想实现不同样式的TrackBar控件，重写这四个函数，可以相应的绘制。DrawTrackBar函数的具体代码： private void DrawTrackBar(IntPtr hWnd) ControlState state = ControlState.Normal; bool horizontal = base.Orientation = Orientation.Horizontal; ImageDc tempDc = new ImageDc(base.Width, base.Height); TrackRECT trackRect = new TrackRECT(); TrackRECT thumbRect = new TrackRECT(); Graphics g = Graphics.FromHdc(tempDc.Hdc); NativeMethods.SendMessage(hWnd, TBM.TBM_GETCHANNELRECT, 0, ref trackRect); NativeMethods.SendMessage(hWnd, TBM.TBM_GETTHUMBRECT, 0, ref thumbRect); Rectangle trackRectangle = horizontal ? trackRect.Rect : Rectangle.FromLTRB(trackRect.Top, trackRect.Left, trackRect.Bottom, trackRect.Right); if (ThumbHovering(thumbRect) if (Helper.LeftKeyPressed() state = ControlState.Pressed; else state = ControlState.Hover; /绘制TrackBar控件的背景 using (PaintEventArgs pe = new PaintEventArgs(g, ClientRectangle) OnRenderBackground(pe); int ticks = NativeMethods.SendMessage(hWnd, TBM.TBM_GETNUMTICS, 0, 0); int thumbOffset = horizontal ? thumbRect.Rect.Width : thumbRect.Rect.Height; int trackWidth = trackRect.Right - trackRect.Left; if (ticks 0) List tickPosList = new List(ticks); float tickSpace = (trackWidth - thumbOffset) / (float)(ticks - 1); float offset = trackRect.Left + thumbOffset / 2f; for(int pos = 0; pos 0) float rangeSpace = iRange = 1 ? 0 : (trackWidth - thumbOffset) / (float)(iRange - 1); float rangeOffset = trackRect.Left + thumbOffset / 2f; /绘制TrackBar控件的轨道 using (PaintTrackEventArgs pe = new PaintTrackEventArgs(g, trackRectangle, rangeSpace, rangeOffset, rangeMin, rangeMax) OnRenderTrack(pe); /绘制TrackBar控件的滑块 using (PaintThumbEventArgs pe = new PaintThumbEventArgs(g, thumbRect.Rect, state) OnRenderThumb(pe); g.Dispose(); IntPtr hDC = NativeMethods.GetDC(hWnd); NativeMethods.BitBlt(hDC, 0, 0, base.Width, base.Height, tempDc.Hdc, 0, 0, 0xCC0020); NativeMethods.ReleaseDC(hWnd, hD