覆蓋C＃窗口應用程序窗體中的透明圖片框？

Question

我想提出一個背景圖像和背景圖像上面我想疊加透明圖片框，並試圖把第二個PictureBox的，像這樣：

pictureBox2.BackColor = Color.Transparent; 

但沒有奏效。基本上，我想這樣做：

Answer 1

透明度Windows Forms尚未實現正如人們所期望。具有透明背景實際上意味着控件使用其父項的背景。這意味着你需要讓你的覆蓋控制原始圖片框的子：

PictureBox overlay = new PictureBox(); 

overlay.Dock = DockStyle.Fill; 
overlay.BackColor = Color.FromArgb(128, Color.Blue); 

pictureBox2.Controls.Add(overlay); 

如果你想覆蓋圖片框包含你需要真正改變圖像的透明圖像：

PictureBox overlay = new PictureBox(); 
overlay.Dock = DockStyle.Fill; 
overlay.BackColor = Color.Transparent; 

Bitmap transparentImage = new Bitmap(overlayImage.Width, overlayImage.Height); 
using (Graphics graphics = Graphics.FromImage(transparentImage)) 
{ 
    ColorMatrix matrix = new ColorMatrix(); 
    matrix.Matrix33 = 0.5f; 

    ImageAttributes attributes = new ImageAttributes(); 
    attributes.SetColorMatrix(matrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap); 

    graphics.DrawImage(overlayImage, new Rectangle(0, 0, transparentImage.Width, transparentImage.Height), 0, 0, overlayImage.Width, overlayImage.Height, GraphicsUnit.Pixel, attributes); 
} 

overlay.Image = transparentImage; 

pictureBox2.Controls.Add(overlay);