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This article mainly explains "how to realize the TrackBar drag bar to change the slider color". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "C # how to achieve TrackBar drag bar to change the slider color" bar!

Principle

The default color of the slider of the 1.TrackBar drag bar is blue. Iterate through each pixel in the TrackBar control to get a pixel with a color of (232.23), and use another color to draw a circle with a diameter of 1 on the pixel.

two。 Add a Boolean value to determine whether the mouse is in the TrackBar.

3. In the mouse entry control event, the Boolean value is true;; in the mouse leave control event, the Boolean value is false.

4. The timer added to the 1ms, and in the timer event, if the Boolean value is true, the method to change the color is referenced.

Defect

Positioning is not very accurate, the y direction will be a little lower, when dragging, there will be a small bug. So when applied to the vertical TrackBar drag bar, you need y-(float) 0.5 when drawing. At this point, the bug will not be obvious and will be able to be used. (the small bug that still exists will leave a mark on the tip of the slider and will leave a mixed trace when dragging, which is a small point that can be further improved.)

Code

How to change the color:

Public class ChangeSliderColor {/ / change slider color (landscape control) public void LevelChangeColor (Bitmap bitmap, Rectangle rectangle,Graphics graphics,Color color,TrackBar trackBar) {bitmap = new Bitmap (trackBar.Width, trackBar.Height); rectangle = new Rectangle (0,0, trackBar.Width, trackBar.Height); graphics = trackBar.CreateGraphics (); trackBar.DrawToBitmap (bitmap, rectangle) For (int x = 0; x

< trackBar.Width; x++) { for (int y = 0;y < trackBar.Height; y++) { color = bitmap.GetPixel(x, y); if (color == Color.FromArgb(23,23,23)) { graphics.DrawEllipse(new Pen(Color.Red), x, y, 1, 1);//这里的new Pen即改变后的颜色 } } } } //改变滑块颜色（竖向控件） public void VerticalChangeColor(Bitmap bitmap, Rectangle rectangle, Graphics graphics, Color color, TrackBar trackBar) { bitmap = new Bitmap(trackBar.Width, trackBar.Height); rectangle = new Rectangle(0, 0, trackBar.Width, trackBar.Height); graphics = trackBar.CreateGraphics(); trackBar.DrawToBitmap(bitmap, rectangle); for (int x = 0; x < trackBar.Width; x++) { for (int y = 0; y < trackBar.Height; y++) { color = bitmap.GetPixel(x, y); if (color == Color.FromArgb(23, 23, 23)) { graphics.DrawEllipse(new Pen(Color.Red), x, y - (float)0.5, 1, 1); } } } } } 引用： Bitmap bitmap; Rectangle rectangle; Graphics graphics; Color color; bool isIntrackBar = false;//判断鼠标是否在trackBar中 private void timer_Tick(object sender, EventArgs e) { if (isIntrackBar == true) { ChangeSliderColor csc = new ChangeSliderColor(); csc.LevelChangeColor(bitmap, rectangle, graphics, color, trackBar); } } //鼠标进入trackBar时，布尔值为true private void trackBar_MouseEnter(object sender, EventArgs e) { isIntrackBar = true; } //鼠标从trackBar中出来时，布尔值为false private void trackBar_MouseLeave(object sender, EventArgs e) { isIntrackBar = false; } 如果是纵向TrackBar，则引用ChangeSliderColor的VerticalChangeColor方法。 如果在一个窗体中，存在多个TrackBar，则每个trackBar一个布尔值，并在每个trackBar的MouseEnter事件中加入timer.Start（），在MouseLeave事件中加入timer.Stop（），并在timer_Tick事件中加入判断。 效果

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