windows phone开发之图片上传

最新推荐文章于 2024-12-20 00:00:00 发布

sunshine_sean

最新推荐文章于 2024-12-20 00:00:00 发布

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分类专栏： Windows Phone

本文链接：https://blog.youkuaiyun.com/u012823326/article/details/16106593

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本文介绍了一个用于上传文件的类，并提供了文件压缩、流操作和文件类型识别的功能。

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/// <summary>
/// 上传文件
/// </summary>
public class UploadFile
{
    public UploadFile()
    { }
    /// <summary>
    /// 根据文件名、文件类型与文件流实现化
    /// </summary>
    /// <param name="fileName">文件名</param>
    /// <param name="stream">文件数据流</param>
    public UploadFile(string fileName, Stream stream)
    {
        this.FileName = System.IO.Path.GetFileName(fileName);
        this.ContentType = GetContentType(this.FileName);
        this.FileStream = stream;
    }

    /// <summary>
    /// 文件名称
    /// </summary>
    public string FileName { get; private set; }

    /// <summary>
    /// 文件类型
    /// </summary>
    public string ContentType { get; private set; }

    /// <summary>
    /// 本地文件路径
    /// </summary>
    private string FilePath { get; set; }
    /// <summary>
    /// 文件数据流
    /// </summary>
    public Stream FileStream { get; private set; }

    /// <summary>
    /// 将当前的文件数据写入到某个数据流中
    /// </summary>
    /// <param name="stream"></param>
    public void WriteTo(Stream stream)
    {
        byte[] buffer = new byte[512];
        int size = 0;

        if (this.FileStream != null)
        {
            //写入文件流
            while ((size = this.FileStream.Read(buffer, 0, buffer.Length)) > 0)
            {
                stream.Write(buffer, 0, size);
            }
        }

        if (!string.IsNullOrEmpty(this.FilePath)
            && File.Exists(this.FilePath))
        {
            //写入本地文件流
            using (System.IO.FileStream reader = new FileStream(this.FilePath, FileMode.Open, FileAccess.Read))
            {
                while ((size = reader.Read(buffer, 0, buffer.Length)) > 0)
                {
                    stream.Write(buffer, 0, size);
                }
            }
        }

    }

    /// <summary>
    /// 根据文件扩展名获取文件类型
    /// </summary>
    /// <param name="fileName">文件名</param>
    /// <returns></returns>
    private static string GetContentType(string fileName)
    {
        var fileExt = System.IO.Path.GetExtension(fileName);
        return GetCommonFileContentType(fileExt);
    }
    /// <summary>
    /// 获取通用文件的文件类型
    /// </summary>
    /// <param name="fileExt">文件扩展名.如".jpg",".gif"等</param>
    /// <returns></returns>
    private static string GetCommonFileContentType(string fileExt)
    {
        switch (fileExt)
        {
            case ".jpg":
            case ".jpeg":
                return "image/jpeg";
            case ".gif":
                return "image/gif";
            case ".bmp":
                return "image/bmp";
            case ".png":
                return "image/png";
            default:
                return "application/octetstream";
        }
    }

    /// <summary>
    /// 压缩图片，只调整质量，不调整分辨率
    /// </summary>
    /// <param name="soucre">图片流</param>
    /// <param name="quality">质量1-100</param>
    public static Stream Compression(Stream soucre)
    {
        var quality = 80;
        soucre.Seek(0, SeekOrigin.Begin);
        var p = quality / 100.0;
        var writeableBitmap = PictureDecoder.DecodeJpeg(soucre);
        var width = writeableBitmap.PixelWidth * p;
        var height = writeableBitmap.PixelHeight * p;
        var outstream = new MemoryStream();
        writeableBitmap.SaveJpeg(outstream, (int)width, (int)height, 0, quality);
        outstream.Seek(0, SeekOrigin.Begin);
        return outstream;
    }
}

然后是前台的调用
[csharp]
/// <summary>
       /// 图片上传处理
       /// </summary>
       /// <param name="sender"></param>
       /// <param name="e"></param>
       private void PhotoChooserTask_Completed(object sender, PhotoResult e)
       {
           try
           {
               if (e.ChosenPhoto != null)
               {
                   Stream s = UploadFile.Compression(e.ChosenPhoto);
                   bytepic = StreamToBytes(s);
                   Encoding myEncoding = Encoding.GetEncoding("utf-8");
                   strpic = Convert.ToBase64String(bytepic);
                   ExistsPic = true;
               }
           }
           catch (Exception)
           {
               throw;
           }
       }
       /// <summary>
       /// 字节流转换byte
       /// </summary>
       /// <param name="stream"></param>
       /// <returns></returns>
       public byte[] StreamToBytes(Stream stream)
       {
           byte[] bytes = new byte[stream.Length];
           stream.Read(bytes, 0, bytes.Length);
           // 设置当前流的位置为流的开始
           stream.Seek(0, SeekOrigin.Begin);
           return bytes;
       }