picShowPDF.Image = Image.FromFile(pathFile);C#怎么把这个图片怎么旋转90°

要旋转图片90度，你可以使用C#中的Graphics类，具体步骤如下：

1. **读取原始图片**[^1]:

   string pathFile = "path_to_your_image.jpg";
   Image originalImage = Image.FromFile(pathFile);

2. **创建一个新的Bitmap来保存旋转后的图像**:

   Bitmap rotatedImage = new Bitmap(originalImage.Width, originalImage.Height);
   Graphics graphics = Graphics.FromImage(rotatedImage);

3. **设置旋转角度并应用到新的Bitmap上**:

   graphics.RotateFlip(RotateFlipType.Rotate180FlipNone, originalImage.Width / 2, originalImage.Height / 2);
   graphics.DrawImage(originalImage, 0, 0);

4. **将旋转后的Bitmap赋值给picShowPDF.Image**:

   picShowPDF.Image = rotatedImage;

完整示例代码：

private void RotateAndDisplayImage(string pathFile)
{
    // Step 1: Read original image
    Image originalImage = Image.FromFile(pathFile);

    // Step 2: Create a new bitmap to hold the rotated image
    Bitmap rotatedImage = new Bitmap(originalImage.Width, originalImage.Height);
    Graphics graphics = Graphics.FromImage(rotatedImage);

    // Step 3: Rotate and flip the image
    graphics.RotateFlip(RotateFlipType.Rotate180FlipNone, originalImage.Width / 2, originalImage.Height / 2);
    graphics.DrawImage(originalImage, 0, 0);

    // Step 4: Assign the rotated image to picShowPDF.Image
    picShowPDF.Image = rotatedImage;
}