这篇文章主要为大家展示了“C#如何实现文件上传下载功能”，内容简而易懂，条理清晰，希望能够帮助大家解决疑惑，下面让小编带领大家一起研究并学习一下“C#如何实现文件上传下载功能”这篇文章吧。
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具体代码如下所示：
//打开Excel文件，转换为DataTable
DataTable dtExcel;
private void OpenFile()
{
OpenFileDialog dialog = new OpenFileDialog();
dialog.Filter = "Microsoft Excel files(*.xls)|*.xls;*.xlsx"; //筛选打开文件类型 ：图片 *.jpg|*.jpg|*.bmp|*.bmp ;"音频文|*.mp3;*.wma;*.aac;*.midi;*.wav" 等等
if (dialog.ShowDialog() == DialogResult.OK)
{
dialogFileName = dialog.FileName;
dtExcel = ExcelToDataTable(dialogFileName, "sheet1", true);
}
}
///
/// Excel转Datatable
///
/// 文件名含后缀名
/// Excel文件，页名称
/// 是否将第一列作为表头
/// 文件下载：
private void DownLoad()
{
if (impdefineBM != null)
{
FolderBrowserDialog path = new FolderBrowserDialog();
path.ShowDialog();
if (path != null && path.SelectedPath != "")
{
string url = @"http://192.168.1.1/XX.xls"; //下载地址
string name = "FileName"; // 文件名称
string savefilepath = path.SelectedPath + "\\" + name + url.Substring(url.LastIndexOf(".")); //注意：下载文件名的命名 ，可根据实际需求调整调用的文件创建方式
MultiDownload download = new MultiDownload(5, url, savefilepath); //调用多线程下载
download.Start();
}
}
}
#region 多线程下载
public class MultiDownload
{
#region 变量
private int _threadNum; //线程数量
private long _fileSize; //文件大小
private string _fileUrl; //文件地址
private string _fileName; //文件名
private string _savePath; //保存路径
private short _threadCompleteNum; //线程完成数量
private bool _isComplete; //是否完成
private volatile int _downloadSize; //当前下载大小(实时的)
private Thread[] _thread; //线程数组
private List _tempFiles = new List();
private object locker = new object();
#endregion
#region 属性
///
/// 文件名
///
public string FileName
{
get
{
return _fileName;
}
set
{
_fileName = value;
}
}
///
/// 文件大小
///
public long FileSize
{
get
{
return _fileSize;
}
}
///
/// 当前下载大小(实时的)
///
public int DownloadSize
{
get
{
return _downloadSize;
}
}
///
/// 是否完成
///
public bool IsComplete
{
get
{
return _isComplete;
}
}
///
/// 线程数量
///
public int ThreadNum
{
get
{
return _threadNum;
}
}
///
/// 保存路径
///
public string SavePath
{
get
{
return _savePath;
}
set
{
_savePath = value;
}
}
#endregion
///
/// 构造函数
///
/// 线程数量
/// 文件Url路径
/// 本地保存路径
public MultiDownload(int threahNum, string fileUrl, string savePath)
{
this._threadNum = threahNum;
this._thread = new Thread[threahNum];
this._fileUrl = fileUrl;
this._savePath = savePath;
}
public void Start()
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_fileUrl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
_fileSize = response.ContentLength;
int singelNum = (int)(_fileSize / _threadNum); //平均分配
int remainder = (int)(_fileSize % _threadNum); //获取剩余的
request.Abort();
response.Close();
for (int i = 0; i < _threadNum; i++)
{
List range = new List();
range.Add(i * singelNum);
if (remainder != 0 && (_threadNum - 1) == i) //剩余的交给最后一个线程
range.Add(i * singelNum + singelNum + remainder - 1);
else
range.Add(i * singelNum + singelNum - 1);
//下载指定位置的数据
int[] ran = new int[] { range[0], range[1] };
_thread[i] = new Thread(new ParameterizedThreadStart(Download));
_thread[i].Name = System.IO.Path.GetFileNameWithoutExtension(_fileUrl) + "_{0}".Replace("{0}", Convert.ToString(i + 1));
_thread[i].Start(ran);
}
//MessageBox.Show("下载完成！");
}
private void Download(object obj)
{
Stream httpFileStream = null, localFileStram = null;
try
{
int[] ran = obj as int[];
string tmpFileBlock = System.IO.Path.GetTempPath() + Thread.CurrentThread.Name + ".tmp";
_tempFiles.Add(tmpFileBlock);
HttpWebRequest httprequest = (HttpWebRequest)WebRequest.Create(_fileUrl);
httprequest.AddRange(ran[0], ran[1]);
HttpWebResponse httpresponse = (HttpWebResponse)httprequest.GetResponse();
httpFileStream = httpresponse.GetResponseStream();
localFileStram = new FileStream(tmpFileBlock, FileMode.Create);
byte[] by = new byte[5000];
int getByteSize = httpFileStream.Read(by, 0, (int)by.Length); //Read方法将返回读入by变量中的总字节数
while (getByteSize > 0)
{
Thread.Sleep(20);
lock (locker) _downloadSize += getByteSize;
localFileStram.Write(by, 0, getByteSize);
getByteSize = httpFileStream.Read(by, 0, (int)by.Length);
}
lock (locker) _threadCompleteNum++;
}
catch (Exception ex)
{
throw new Exception(ex.Message.ToString());
}
finally
{
if (httpFileStream != null) httpFileStream.Dispose();
if (localFileStram != null) localFileStram.Dispose();
}
if (_threadCompleteNum == _threadNum)
{
Complete();
_isComplete = true;
}
}
///
/// 下载完成后合并文件块
///
private void Complete()
{
Stream mergeFile = null;
BinaryWriter AddWriter = null;
try
{
using (mergeFile = new FileStream(@_savePath, FileMode.Create)) //根据实际情况调整FileMode
{
AddWriter = new BinaryWriter(mergeFile);
foreach (string file in _tempFiles)
{
using (FileStream fs = new FileStream(file, FileMode.Open))
{
BinaryReader TempReader = new BinaryReader(fs);
AddWriter.Write(TempReader.ReadBytes((int)fs.Length));
TempReader.Close();
}
File.Delete(file);
}
}
MyMessageBox.Show("下载完成！");
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (AddWriter != null)
{
AddWriter.Close();
AddWriter.Dispose();
}
if (mergeFile != null)
{
mergeFile.Close();
mergeFile.Dispose();
}
}
}
} 以上是“C#如何实现文件上传下载功能”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注创新互联行业资讯频道！
