c# - 创建一个透明的图片框类

Question

我的问题是我想在按钮上放置一个带有 png 的图片框，但 WinForms 似乎不支持那里的透明度。1. 是的，我试过 Parent 2. 是的，我试过 Color.Transparent

我最后一次尝试也没有工作，我对此一无所知。也许你可以帮助我。然而，这是我迄今为止最接近的尝试。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace Parameter2
{
    public class TransPicturebox : Control
    {
        public TransPicturebox()
        {
            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.ResizeRedraw | ControlStyles.SupportsTransparentBackColor | ControlStyles.UserPaint, true);
            this.BackColor = Color.Transparent;
        }

        private Image _Image;

        public Image Image
        {
            get
            {
                return _Image;
            }
            set
            {
                _Image = value;
            }
        }

        private bool _autoscale = true;

        public bool AutoScale
        {
            get
            {
                return _autoscale;
            }
            set
            {
                _autoscale = value;
            }
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            if (_Image != null) //keep from crashing if there is no image
            {
                if (_autoscale)
                {
                    //Auto Scale the image to fit in the text box
                    Rectangle rectangle = new Rectangle();
                    Size size = this.Image.Size;
                    float num = Math.Min((float)(((float)base.ClientRectangle.Width) / ((float)size.Width)), (float)(((float)base.ClientRectangle.Height) / ((float)size.Height)));
                    rectangle.Width = (int)(size.Width * num);
                    rectangle.Height = (int)(size.Height * num);
                    rectangle.X = (base.ClientRectangle.Width - rectangle.Width) / 2;
                    rectangle.Y = (base.ClientRectangle.Height - rectangle.Height) / 2;

                    e.Graphics.DrawImage(_Image, rectangle);
                }
                else
                {
                    e.Graphics.DrawImage(_Image, new Point(0, 0));
                }
            }
        }
    }
}