c# - 透明背景显示黑色

Question

我试图让一张图片出现在另一张图片之上，并且仍然通过透明背景显示下方的图片。我明白了，所以新图像出现在另一个图像之上，但是将 BackColor 设置为 Color.Transparent 只会导致黑色背景。

完整代码:

public partial class frm_airportApplication : Form
{
    PictureBox PicBox;
    public frm_airportApplication()
    {
        InitializeComponent();
    }
    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.ExStyle |= 0x000000200;
            return cp;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        AllowTransparency = true;
        plane p = new plane();
        p.getPB().Parent = pb_airport;
        this.Controls.Add(p.getPB());
        this.Update();
    }
    protected void InvalidateEx()
    {
        if (Parent == null)
            return;
        Rectangle rc = new Rectangle(this.Location, this.Size);
        Parent.Invalidate(rc, true);
    }
    protected override void OnPaintBackground(PaintEventArgs pevent)
    {
        //do not allow the background to be painted 
    }

    private void button2_Click(object sender, EventArgs e)
    {
        AllowTransparency = true;
        ResourceManager resourceManager = new ResourceManager("Airport_Application.Properties.Resources", GetType().Assembly); 
        PicBox = new PictureBox();
        PicBox.BackColor = Color.Transparent;
        PicBox.Image = (Bitmap)resourceManager.GetObject("plane_icon");
        PicBox.Top = 100;
        PicBox.Width = 120;
        PicBox.Height = 120;
        PicBox.Left = 10;
        PicBox.SizeMode = PictureBoxSizeMode.Zoom;

        PicBox.Parent = pb_airport;
        Controls.Add(PicBox);
        PicBox.BringToFront();
    }
}
public class plane
{
    PictureBox pb;
    Bitmap image;
    ResourceManager resourceManager;
    public plane()
    {
        resourceManager = new ResourceManager("Airport_Application.Properties.Resources", GetType().Assembly);
        image=(Bitmap)resourceManager.GetObject("plane_icon");
        pb = new PictureBox();
        pb.Image = image;
        pb.Top = 500;
        pb.Width = 100;
        pb.Height = 100;
        pb.Left = 50;
        pb.SizeMode = PictureBoxSizeMode.Zoom;
        pb.BackColor = Color.Transparent;
    }
    public PictureBox getPB()
    {
        return pb;
    }
}

我发现很多人都遇到过类似的问题，但没有一个解决方案有帮助。

Answer 1

已经有一段时间了，但我认为您必须将表单设置为允许透明胶片

this.AllowTransparency = true;
or
YourForm.AllowTransparency = true;

这样可以去掉黑色