Question

C# web 判断下载是否完成

Answer 1

用下列代码可以下载服务器上的一个文件到客户端，并完成下载。
FileInfo DownloadFile = new FileInfo(filePath);

//----可以下载大附件
System.IO.Stream iStream = null;

// Buffer to read 10K bytes in chunk:
byte[] buffer = new Byte[10000];

// Length of the file:
int length;

// Total bytes to read:
long dataToRead;

try
{
// Open the file.
iStream = new System.IO.FileStream(filePath, System.IO.FileMode.Open,
System.IO.FileAccess.Read,System.IO.FileShare.Read);

// Total bytes to read:
dataToRead = iStream.Length;

Response.ContentType = "application/octet-stream; Charset=UTF8";
Response.AddHeader("Content-Disposition", "attachment; filename="+System.Web.HttpUtility.UrlEncode(fileName,System.Text.Encoding.UTF8));
// Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);

// Read the bytes.
while (dataToRead > 0)
{
// Verify that the client is connected.
if (Response.IsClientConnected)
{
// Read the data in buffer.
length = iStream.Read(buffer, 0, 10000);

// Write the data to the current output stream.
Response.OutputStream.Write(buffer, 0, length);

// Flush the data to the HTML output.
Response.Flush();

buffer= new Byte[10000];
dataToRead = dataToRead - length;
}
else
{
//prevent infinite loop if user disconnects
dataToRead = -1;
}
}
}
catch (Exception ex)
{
// Trap the error, if any.
Response.Clear();
Response.Write("<script language='text/javascript'>");
Response.Write("alert(\""+ex.Message+",下载文件时发生错误\");");
Response.Write("window.close();");
Response.Write("</script>");
Response.End();

}
finally
{
if (iStream != null)
{
//Close the file.
iStream.Close();
}
Response.Close();
}