一、自定义颜色

this.BackColor = Color.FromArgb(255, 255, 255);//红、绿、蓝

应用于Pen、Brush、SolidBrush等：

private Pen CustomizePenColor = new Pen(Color.FromArgb(0, 0, 0));//自定义RGB

private Brush CustomizeBrushColor = new SolidBrush(Color.FromArgb(0, 0, 0));//自定义RGB

private SolidBrush = new SolidBrush(Color.FromArgb(200, 200, 200))；

//在位置(0,0)处绘制一个宽为40，高为30的rgb色值为(200,200,200)的实心矩形
e.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(200, 200, 200)), 0, 0, 40, 30);

二、Web颜色

this.BackColor = Color.Lime;

三、系统

this.BackColor = System.Drawing.SystemColors.Control;

四、其他

private Pen pencolor = Pens.Red;//系统自带颜色
private Brush brushcolor = Brushes.White;

五、取色

1、Color颜色RGB对照表

https://blog.csdn.net/qq_38974638/article/details/108718402

2、颜色混搭

https://www.runoob.com/tags/colors-mixer.html

3、取色器/拾色器

https://www.runoob.com/tags/html-colorpicker.html

4、颜色值

https://www.runoob.com/html/html-colorvalues.html