在浏览器中下载及打开文件的代码

    在asp.net中，下载文件和在浏览器中打开文件是经常使用的一个功能。

    其中的关键点有三个：
        [b] 1 ContentType 
[/b]2 URL
    3Content-disposition

1 ContentType

表示类容类型决定浏览器将以什么形式、什么编码读取这个文件。

例如myimage.gif，表示输出gif图片，application/pdf表示输入pdf文档，application/msword表示输出word文档
常见ContentType

2URL

由于需要用到某一个文件，而文件经常是中文的，这就需要处理url，否则就有可能出现乱码，导致下载打开失败。

3Content-disposition

这则是控制在浏览器中下载还是直接打开文档。需要说明的是，打开的代码，可能由于浏览器的不同，也有可能不会在浏览器中打开，而出现必选在保存再打开的情况。
打开下载代码

/// <summary>
/// 在浏览器中打开文件，由于浏览器的不同，也有可能不会打开文件，而是变成了必须保存后才能打开
/// </summary>
/// <param name="filpath"></param>
/// <param name="filename"></param>
public static void OpenFile(string filpath, string filename)
{
long fileSize = 0;
byte[] fileBuffer;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.CacheControl = "no-cache";
HttpContext.Current.Response.AppendHeader("Pragma", "No-Cache");
HttpContext.Current.Response.ContentType = "application/pdf;";//输出类型
HttpContext.Current.Response.Charset = "charset=utf-8";
HttpContext.Current.Response.AddHeader("Content-Disposition", "inline; filename=\"" + UrlEncode(filename) + "\";");//在浏览器中打开文档，对文件名进行处理

using (FileStream fileStream = new FileStream(filpath, FileMode.Open, FileAccess.Read))
{
fileSize = fileStream.Length;
fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);
fileStream.Close();
}
HttpContext.Current.Response.BinaryWrite(fileBuffer);
HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());//文件大小
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();

}
/// <summary>
/// 在浏览器中下载文件
/// </summary>
/// <param name="filpath"></param>
/// <param name="filename"></param>
public static void DownFile(string filpath, string filename)
{
long fileSize = 0;
byte[] fileBuffer;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.CacheControl = "no-cache";
HttpContext.Current.Response.AppendHeader("Pragma", "No-Cache");
HttpContext.Current.Response.ContentType = "application/pdf;";//输出类型
HttpContext.Current.Response.Charset = "charset=utf-8";//编码
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + UrlEncode(filename) + "\";");//在浏览器中打开文档，对文件名进行处理

using (FileStream fileStream = new FileStream(filpath, FileMode.Open, FileAccess.Read))
{
fileSize = fileStream.Length;
fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);
fileStream.Close();
}
HttpContext.Current.Response.BinaryWrite(fileBuffer);
HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());//文件大小
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();

}
private static string UrlEncode(string filename)
{

return HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8);

}

代码2

public class OpenDownFile
{
/// <summary>
/// 在浏览器中打开文件，由于浏览器的不同，也有可能不会打开文件，而是变成了必须保存后才能打开
/// </summary>
/// <param name="filpath"></param>
/// <param name="filename"></param>
public static void OpenFile(string filpath, string filename,string filetype)
{
long fileSize = 0;
byte[] fileBuffer;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.CacheControl = "no-cache";
HttpContext.Current.Response.AppendHeader("Pragma", "No-Cache");
HttpContext.Current.Response.ContentType = filetype;//输出类型
HttpContext.Current.Response.Charset = "charset=utf-8";
HttpContext.Current.Response.AddHeader("Content-Disposition", "inline; filename=\"" + UrlEncode(filename) + "\";");//在浏览器中打开文档，对文件名进行处理

using (FileStream fileStream = new FileStream(filpath, FileMode.Open, FileAccess.Read))
{
fileSize = fileStream.Length;
fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);
fileStream.Close();
}
HttpContext.Current.Response.BinaryWrite(fileBuffer);
HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());//文件大小
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();

}
/// <summary>
/// 在浏览器中下载文件
/// </summary>
/// <param name="filpath"></param>
/// <param name="filename"></param>
public static void DownFile(string filpath, string filename,string filetype)
{
long fileSize = 0;
byte[] fileBuffer;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.CacheControl = "no-cache";
HttpContext.Current.Response.AppendHeader("Pragma", "No-Cache");
HttpContext.Current.Response.ContentType =filetype;//输出类型
HttpContext.Current.Response.Charset = "charset=utf-8";//编码
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + UrlEncode(filename) + "\";");//在浏览器中打开文档，对文件名进行处理

using (FileStream fileStream = new FileStream(filpath, FileMode.Open, FileAccess.Read))
{
fileSize = fileStream.Length;
fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);
fileStream.Close();
}
HttpContext.Current.Response.BinaryWrite(fileBuffer);
HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());//文件大小
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();

}
private static string UrlEncode(string filename)
{

return HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8);

}
}