C#中 读取图片后不锁定图片的方法

 

            //170216.JJ method that will lock image file:
            //picConn.Image = Image.FromFile(strPath);

            //170216.JJ method that will unlock after read.
            Image img;
            using (var bmpTemp = new Bitmap(strPath))
            {
                img = new Bitmap(bmpTemp);
            }
            picConn.Image = img;

 ----------------------

2018.06.01 今天又有了新的需求，需要加载GIF动画，所以之前的new Bitmap就不行了。

可以通过stream的形式读取.

 using (FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read))
            {
                gifImage = Image.FromStream(stream);
}

但是读取完就不能实时换帧,调用gifImage.SelectActiveFrame(dimension, i)的时候会报错。

只好一次性把所有的帧都读回来，存起来。

代码如下：亲测可用

    public class GifImage
    {
        private Image gifImage;
        private FrameDimension dimension;
        private Image[] imgList;
        private int frameCount;
        private int currentFrame = -1;
        private bool reverse;
        private int step = 1;

        public GifImage(string path)
        {
            //gifImage = Image.FromFile(path);// This method would lock the file

            using (FileStream stream = new FileStream(path, FileMode.Open, FileAccess.Read))
            {
                gifImage = Image.FromStream(stream);

                //initialize
                dimension = new FrameDimension(gifImage.FrameDimensionsList[0]);
                //gets the GUID
                //total frames in the animation
                frameCount = gifImage.GetFrameCount(dimension);

                //Store each frame
                imgList = new Image[frameCount];
                for (int i = 0; i < frameCount; i++)
                {
                    gifImage.SelectActiveFrame(dimension, i);//This action requires the stream opened.
                    imgList[i] = (Image)gifImage.Clone();
                }

            }
        }

        public bool ReverseAtEnd
        {
            //whether the gif should play backwards when it reaches the end
            get { return reverse; }
            set { reverse = value; }
        }

        public Image GetNextFrame()
        {

            currentFrame += step;

            //if the animation reaches a boundary...
            if (currentFrame >= frameCount || currentFrame < 1)
            {
                if (reverse)
                {
                    step *= -1;
                    //...reverse the count
                    //apply it
                    currentFrame += step;
                }
                else
                {
                    currentFrame = 0;
                    //...or start over
                }
            }
            return GetFrame(currentFrame);
        }

        public Image GetFrame(int index)
        {
            return imgList[index];

            // gifImage.SelectActiveFrame(dimension, index);
            // //find the frame
            // return (Image)gifImage.Clone();
            // //return a copy of it
        }
    }

参考文章：

https://stackoverflow.com/questions/13485477/can-a-picturebox-show-animated-gif-in-windows-application

https://stackoverflow.com/questions/6576341/open-image-from-file-then-release-lock