mvc 下载示例(from AllInOne Code Framework)

　　本例实现了浏览服务器端文件和选中文件列表中某一文件进行下载。

　　FileController：

　　

public class FileController : Controller
    {
        // Action for list all the files in "~/App_Data/download" directory
        public ActionResult List()
        {

            // Retrive file list
            DirectoryInfo dir = new DirectoryInfo(Server.MapPath("~/App_Data/download/"));

            // Filter it via LINQ to Object
            var files = from f in dir.GetFiles("*.*", SearchOption.TopDirectoryOnly)
                        where f.Extension != "exe"
                        select f;
            
            // Call the corresponding View
            return View(files.ToList());
        }

        // Action for return the binary stream of a specified file
        public ActionResult Download(string fn)
        {
            // Check whether requested file is valid
            string pfn = Server.MapPath("~/App_Data/download/" + fn);
            if (!System.IO.File.Exists(pfn))
            {
                throw new ArgumentException("Invalid file name or file not exists!");
            }

            // Use BinaryContentResult to encapsulate the filecontent and return it
            return new BinaryContentResult()
            {
                FileName = fn,
                ContentType = "application/octet-stream",
                Content = System.IO.File.ReadAllBytes(pfn)
            };

        }
    }

　　BinaryContentResult 类定义：

　　

    public class BinaryContentResult : ActionResult
    {
        // Default constructor
        public BinaryContentResult()
        {
        }

        // Properties for encapsulating http headers
        public string ContentType { get; set; }
        public string FileName { get; set; }
        public byte[] Content { get; set; }

        // Underlying code which set the httpheaders and output file content
        public override void ExecuteResult(ControllerContext context)
        {

            context.HttpContext.Response.ClearContent();
            context.HttpContext.Response.ContentType = ContentType;

            context.HttpContext.Response.AddHeader("content-disposition",

            "attachment; filename=" + FileName);

            context.HttpContext.Response.BinaryWrite(Content);
            context.HttpContext.Response.End();
        }
    }

　　由上面的定义我们可以看到，我们可以重载不同的ActionResult。ActionResult类定义如下：

namespace System.Web.Mvc
{
    // 摘要:
    //     Encapsulates the result of an action method and is used to perform a framework-level
    //     operation on the action method's behalf.
    public abstract class ActionResult
    {
        protected ActionResult();

        // 摘要:
        //     Enables processing of the result of an action method by a custom type that
        //     inherits from System.Web.Mvc.ActionResult.
        //
        // 参数:
        //   context:
        //     The context within which the result is executed.
        public abstract void ExecuteResult(ControllerContext context);
    }
}

　　我感觉这个示例比较好，思路很清晰。此示例对我感觉最深的是提供一个mvc下载文件的解决方案，还有我们可以自己定义一个能满足自己需要的ActionResult类。