c下载提取的图像

Question

我创建了一个提取图像的表单应用程序，我搜索了很多帖子，直到现在我可以下载到MemoryStream（字节数组）中。我无法将该字节数组保存到文件系统中并检查图像大小。。。。

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    public List<string> FetchImages(string Url)
    {
        List<string> imageList = new List<string>();

        if (!Url.StartsWith("http://") && !Url.StartsWith("https://"))
            Url = "http://" + Url;
        string responseUrl = string.Empty;
        string htmlData = ASCIIEncoding.ASCII.GetString(DownloadData(Url, out responseUrl));
        if (responseUrl != string.Empty)
            Url = responseUrl;
        if (htmlData != string.Empty)
        {
            string imageHtmlCode = "<img";
            string imageSrcCode = @"src=""";
            int index = htmlData.IndexOf(imageHtmlCode);
            while (index != -1)
            {
                htmlData = htmlData.Substring(index);

                int brackedEnd = htmlData.IndexOf('>'); //make sure data will be inside img tag
                int start = htmlData.IndexOf(imageSrcCode) + imageSrcCode.Length;
                int end = htmlData.IndexOf('"', start + 1);
                    if (end > start && start < brackedEnd)
                {
                    string loc = htmlData.Substring(start, end - start);
                        imageList.Add(loc);
                }
                    if (imageHtmlCode.Length < htmlData.Length)
                    index = htmlData.IndexOf(imageHtmlCode, imageHtmlCode.Length);
                else
                    index = -1;
            }
                for (int i = 0; i < imageList.Count; i++)
            {
                string img = imageList[i];
                string baseUrl = GetBaseURL(Url);
                if ((!img.StartsWith("http://") && !img.StartsWith("https://"))
                    && baseUrl != string.Empty)
                    img = baseUrl + "/" + img.TrimStart('/');
                imageList[i] = img;
            }
        }
        return imageList;
    }

    private byte[] DownloadData(string Url)
    {
        string empty = string.Empty;
        return DownloadData(Url, out empty);
    }
    private byte[] DownloadData(string Url, out string responseUrl)
    {
        byte[] downloadedData = new byte[0];
        try
        {
                WebRequest req = WebRequest.Create(Url);
            WebResponse response = req.GetResponse();
            Stream stream = response.GetResponseStream();
            responseUrl = response.ResponseUri.ToString();
                byte[] buffer = new byte[1024];

            MemoryStream memStream = new MemoryStream();
            while (true)
            {
                int bytesRead = stream.Read(buffer, 0, buffer.Length);
                if (bytesRead == 0)
                {
                    break;
                }
                else
                {
                    memStream.Write(buffer, 0, bytesRead);
                }
            }
                downloadedData = memStream.ToArray();
                stream.Close();
            memStream.Close();
        }
        catch (Exception)
        {
            responseUrl = string.Empty;
            return new byte[0];
        }
        return downloadedData;
    }
    private Image ImageFromURL(string Url)
    {
        byte[] imageData = DownloadData(Url);
        Image img = null;
        try
        {
            MemoryStream stream = new MemoryStream(imageData);
            img = Image.FromStream(stream);
            stream.Close();
        }
        catch (Exception)
        {
        }
        return img;
    }
    private string GetBaseURL(string Url)
    {
        int inx = Url.IndexOf("://") + "://".Length;
        int end = Url.IndexOf('/', inx);
        string baseUrl = string.Empty;
        if (end != -1)
            return Url.Substring(0, end);
        else
            return string.Empty;
    }
    private void btnGetImages_Click(object sender, EventArgs e)
    {              
        this.Cursor = Cursors.WaitCursor;
        listImages.Items.Clear();
        foreach (string image in FetchImages(txtURL.Text))
        {
            listImages.Items.Add(image);
        }
        this.Cursor = Cursors.Default;
    }
    private void btnView_Click(object sender, EventArgs e)
    {
        if (listImages.SelectedIndex != -1)
            picImage.Image = ImageFromURL(listImages.SelectedItem.ToString());
    }
    private void btnSave_Click(object sender, EventArgs e)
    {
    }
    private void btnDownload_Click(object sender, EventArgs e)
    {
        DownloadData(txtURL.Text);
    }

我正试图将memroy流保存到硬盘中，但仍然没有得到确切的代码，

我认为这个代码需要一些额外的更改

 MemoryStream memStream = new MemoryStream();
                while (true)
                {
                    //Try to read the data
                    int bytesRead = stream.Read(buffer, 0, buffer.Length);
                    if (bytesRead == 0)
                    {
                        break;
                    }
                    else
                    {
                        //Write the downloaded data
                        memStream.Write(buffer, 0, bytesRead);
                    }
                }

如有任何帮助，我们将不胜感激。

Answer 1

如果要将Byte[]数组保存到文件中，

语法：File.WriteAllBytes(string path, byte[] bytes)

例如：File.WriteAllBytes("Foo.txt", arrBytes); // Requires System.IO

请参阅此链接了解更多信息http://msdn.microsoft.com/en-us/library/system.io.file.writeallbytes.aspx

如果您想将字节转换回图像并保存到驱动器中。例如：

byte[] bitmap = YourImage();
using(Image image = Image.FromStream(new MemoryStream(bitmap)))
{
  image.Save("image.jpg", ImageFormat.Jpeg);
}