c# - 创建自定义文件下载。 MD5 哈希值不匹配

Question

我使用 Asp.Net MVC 创建了一个文件下载器。内置 Asp.Net MVC 函数的问题在于它们无法处理超大文件下载，并且在某些浏览器中它们不会弹出另存为对话框。所以我使用来自 msdn http://support.microsoft.com/kb/812406 的文章自己滚动.现在的问题是文件下载完美，但 MD5 校验和不匹配，因为服务器上的文件大小与下载的文件大小略有不同(尽管 1000 次测试表明下载执行得很好)。这是代码:

public class CustomFileResult : ActionResult
{
    public string File { get; set; }

    public CustomFileResult(string file)
    {
        this.File = file;
    }

    public override void ExecuteResult(ControllerContext context)
    {
        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;

        // Identify the file name.
        string filename = System.IO.Path.GetFileName(this.File);

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


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

            context.HttpContext.Response.ContentType = "application/octet-stream";
            context.HttpContext.Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);

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

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

                    // Flush the data to the HTML output.
                    context.HttpContext.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.
            context.HttpContext.Response.Write("Error : " + ex.Message);
        }
        finally
        {
            if (iStream != null)
            {
                //Close the file.
                iStream.Close();
            }
            context.HttpContext.Response.Close();
        }
    }
}

和执行:

return new CustomFileResult(file.FullName);

Answer 1

尝试使用

Response.TransmitFile(string fileName) 

方法。

它真的很好，并且有一些东西可以避免 OutOfMemory 预期。

http://msdn.microsoft.com/en-us/library/12s31dhy(v=vs.80).aspx