C# WinForm 自定义控件，DataGridView背景透明，TabControl背景透明

 注意: 以下代码，属性直接赋值的语法糖要vs2015以上才支持。

 using System.ComponentModel;
 using System.Drawing;
 using System.Windows.Forms;
 namespace RaywindStudio.Components
 {
     public class TabCtrlX : TabControl
     {
         public TabCtrlX()
         {
             InitializeComponent();
             this.SetStyle(ControlStyles.UserPaint, true);//用户自己绘制
             this.SetStyle(ControlStyles.ResizeRedraw, true);
             this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
             this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
             //让控件支持透明色
             this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
         }

         #region designer
         /// <summary>
         /// 必需的设计器变量。
         /// </summary>
         private System.ComponentModel.IContainer components = null;

         /// <summary>
         /// 清理所有正在使用的资源。
         /// </summary>
         /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
         protected override void Dispose(bool disposing)
         {
             if (disposing && (components != null))
             {
                 components.Dispose();
             }
             base.Dispose(disposing);
         }

         #region 组件设计器生成的代码

         /// <summary>
         /// 设计器支持所需的方法 - 不要
         /// 使用代码编辑器修改此方法的内容。
         /// </summary>
         private void InitializeComponent()
         {
             components = new System.ComponentModel.Container();
         }

         #endregion
         #endregion
         //[EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public override Color BackColor {
             get {
                 return Color.FromArgb(Alpha, BgColor);
             }
             set {
                 Alpha = BackColor.A;
                 BgColor = BackColor;
             }
         }

         [DisplayName("Color.Alpha")]
         [CategoryAttribute("Color"), DescriptionAttribute("Opacity不透明度0--255")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public byte Alpha { get; set; } = ;

         [DisplayName("Color.BgColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabControl工作区背景色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color BgColor { get; set; } = Color.White;

         [DisplayName("Color.BordColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabControl边线颜色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color BordColor { get; set; } = Color.LightGray;

         [DisplayName("Color.TitleColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabPage标头背景色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color TitleColor { get; set; } = Color.WhiteSmoke;

         [DisplayName("Color.TitleSeleColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabPage标头选中背景色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color TitleSeleColor { get; set; } = Color.White;

         [DisplayName("Color.TextColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabPage标题颜色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color TextColor { get; set; } = Color.Gray;

         [DisplayName("Color.TextSeleColor")]
         [CategoryAttribute("Color"), DescriptionAttribute("TabPage选中标题颜色")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Color TextSeleColor { get; set; } = Color.Black;

         protected override void OnPaint(PaintEventArgs e)
         {
             this.DrawTitle(e.Graphics);
             base.OnPaint(e);
             DrawBorder(e.Graphics);
         }

         protected void DrawBorder(Graphics g)
         {
             g.DrawRectangle(new Pen(BordColor, 1F), ClientRectangle);
         }

         protected void DrawTitle(Graphics g)
         {
             StringFormat sf = new StringFormat();
             sf.Alignment = StringAlignment.Center;
             sf.LineAlignment = StringAlignment.Center;
             using (SolidBrush sb = new SolidBrush(SystemColors.Control))
             {
                 for (int i = ; i < this.TabPages.Count; i++)
                 {
                     Rectangle rect = this.GetTabRect(i);
                     if (this.SelectedIndex == i)
                     {
                         sb.Color = TitleSeleColor;
                         g.FillRectangle(sb, rect);
                         g.DrawString(this.TabPages[i].Text, this.Font, new SolidBrush(TextSeleColor), rect, sf);
                     }
                     else
                     {
                         sb.Color = TitleColor;
                         g.FillRectangle(sb, rect);
                         g.DrawString(this.TabPages[i].Text, this.Font, new SolidBrush(TextColor), rect, sf);
                     }
                 }
             }
         }
     }
 }

TabCtrlX

 using System.ComponentModel;
 using System.Drawing;
 using System.Windows.Forms;

 namespace RaywindStudio.Components
 {

     public partial class DataGViewX : DataGridView
     {
         public DataGViewX()
         {
             InitializeComponent();
             this.SetStyle(ControlStyles.UserPaint, true);//用户自己绘制
             this.SetStyle(ControlStyles.ResizeRedraw, true);
             this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
             this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
             this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
         }

         private System.ComponentModel.IContainer components = null;
         protected override void Dispose(bool disposing)
         {
             if (disposing && (components != null))
             {
                 components.Dispose();
             }
             base.Dispose(disposing);
         }
         private void InitializeComponent()
         {
             components = new System.ComponentModel.Container();
         }

         [DescriptionAttribute("自定义背景图：当BackTransparent=True时，忽略此设置，直接使用父容器背景")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public Image BackImage { get; set; }

         [DescriptionAttribute("背景透明：当True时，直接使用父容器背景。否则使用BackImage填充背景")]
         [EditorBrowsable(EditorBrowsableState.Always), Browsable(true)]
         public bool BackTransparent { get; set; } = true;

         protected override void PaintBackground(Graphics graphics, Rectangle clipBounds, Rectangle gridBounds)
         {
             base.PaintBackground(graphics, clipBounds, gridBounds);
             if(BackTransparent)
                 BackImage = GetBackImage(this.Parent, this.Left, this.Top, this.Width, this.Height);
             if (BackImage != null)
                 graphics.DrawImage(BackImage, clipBounds);
         }

         public Bitmap GetBackImage(Control parent, int x, int y, int w, int h)
         {
             if (parent.BackgroundImage != null)
             {
                 Bitmap bt = new Bitmap(parent.Width, parent.Height);
                 PictureBox pb = new PictureBox();
                 pb.Size = parent.Size;
                 pb.BackgroundImage = parent.BackgroundImage;
                 pb.BackgroundImageLayout = parent.BackgroundImageLayout;
                 pb.DrawToBitmap(bt, pb.DisplayRectangle);
                 pb.Dispose();
                 Bitmap destBitmap = new Bitmap(w, h);
                 Graphics g = Graphics.FromImage(destBitmap);
                 g.DrawImage(bt, new Rectangle(, , w, h), new Rectangle(x, y, w, h), GraphicsUnit.Pixel);
                 bt.Dispose();
                 g.Dispose();
                 return destBitmap;
             }
             else
                 return null;
         }
     }

 }

DataGViewX