How to download/open the file that I retrive by server path?

问题

I am making a module that shows the tree view of documents that are stores on my drive in a folder. It is retrieving well. But the problem is that the documents are in different format like(.pdf, .docx etc). That are not opening in browser on click. There it shows a 404.4 error. So Tell me how can I download/open different format files through button click? The following is my code:

   protected void Page_Load(System.Object sender, System.EventArgs e)
    {
        try
        {
            if (!Page.IsPostBack)
            {
                if (Settings["DirectoryPath"] != null)
                {
                    BindDirectory(Settings["DirectoryPath"].ToString());
                }
                else
                {
                    BindDirectory(Server.MapPath("~/"));
                }
            }
        }
        catch (DirectoryNotFoundException DNEx)
        {
            try
            {
                System.IO.Directory.CreateDirectory("XIBDir");
                BindDirectory(Server.MapPath("XIBDir"));
            }
            catch (AccessViolationException AVEx)
            {
                Response.Write("<!--" + AVEx.Message + "-->");
            }

        }
        catch (Exception exc) //Module failed to load
        {
            Exceptions.ProcessModuleLoadException(this, exc);
        }

    }

    #endregion

    #region Optional Interfaces

    /// -----------------------------------------------------------------------------
    /// <summary>
    /// Registers the module actions required for interfacing with the portal framework
    /// </summary>
    /// <value></value>
    /// <returns></returns>
    /// <remarks></remarks>
    /// <history>
    /// </history>
    /// -----------------------------------------------------------------------------
    public ModuleActionCollection ModuleActions
    {
        get
        {
            ModuleActionCollection Actions = new ModuleActionCollection();
            Actions.Add(this.GetNextActionID(), Localization.GetString(ModuleActionType.AddContent, this.LocalResourceFile), ModuleActionType.AddContent, "", "", this.EditUrl(), false, SecurityAccessLevel.Edit, true, false);
            return Actions;
        }
    }

    #endregion

    private void BindDirectory(string Path)
    {
        try
        {
            System.IO.DirectoryInfo dirRoot = new System.IO.DirectoryInfo(Path);

            TreeNode tnRoot = new TreeNode(Path);
            tvDirectory.Nodes.Add(tnRoot);

            BindSubDirectory(dirRoot, tnRoot);
            tvDirectory.CollapseAll();
        }
        catch (UnauthorizedAccessException Ex)
        {
            TreeNode tnRoot = new TreeNode("Access Denied");
            tvDirectory.Nodes.Add(tnRoot);
        }
    }

    private void BindSubDirectory(System.IO.DirectoryInfo dirParent, TreeNode tnParent)
    {
        try
        {
            foreach (System.IO.DirectoryInfo dirChild in dirParent.GetDirectories())
            {
                //TreeNode tnChild = new TreeNode(dirChild.Name);
                TreeNode tnChild = new TreeNode(dirChild.Name, dirChild.FullName);

                tnParent.ChildNodes.Add(tnChild);

                BindSubDirectory(dirChild, tnChild);
            }
        }
        catch (UnauthorizedAccessException Ex)
        {
            TreeNode tnChild = new TreeNode("Access Denied");
            tnParent.ChildNodes.Add(tnChild);
        }
    }


    private void BindFiles(string Path)
    {
        try
        {
            tvFile.Nodes.Clear();
            System.IO.DirectoryInfo dirFile = new System.IO.DirectoryInfo(Path);

            foreach (System.IO.FileInfo fiFile in dirFile.GetFiles("*.*"))
            {
                string strFilePath = Server.MapPath(fiFile.Name);
                string strFilePaths = "~/" + fiFile.FullName.Substring(15);

                TreeNode tnFile = new TreeNode(fiFile.Name, fiFile.FullName, "", strFilePaths, "_blank");
                tvFile.Nodes.Add(tnFile);
            }
        }
        catch (Exception Ex)
        {
            Response.Write("<!--" + Ex.Message + "-->");
        }
    }
    protected void tvDirectory_SelectedNodeChanged(object sender, EventArgs e)
    {
        try
        {
            string strFilePath = tvDirectory.SelectedNode.Value;
            BindFiles(tvDirectory.SelectedNode.Value);
        }
        catch (Exception Ex)
        {
            Response.Write("<!--" + Ex.Message + "-->");
        }
    }
}

}

回答1:

404.4 means that the web server (IIS presumably) does not now how to serve the file (based on extension). If your code is serving other files correctly, this is a web server configuration issue. Check your servers documentation for adding the appropriate handlers for the file extensions that aren't working.

回答2:

I would use a hyperlink in your treeview that opens the link: openfile.ashx?path=[insertpathhere] (make sure that your link opens in target="_blank")

within your Generic Handler (ASHX) you have access to load a file from Disk, and stream its bytes into the responseStream. and that will cause the file to download at the browser. You should also set the content-type where applicable.

Code Sample Requested...

Preface: There are some "extra" things going on here... I base64 Encoded the path in my example because I didnt want the path to be 'human-readable'. Also, when I handed it off to the browser I am pre-pending 'export-' plus a timestamp... but you get the idea...

public class getfile : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        var targetId = context.Request.QueryString["target"];
        if (string.IsNullOrWhiteSpace(targetId))
        {
            context.Response.ContentType = "text/plain";
            context.Response.Write("Fail: Target was expected in querystring.");
            return;
        }
        try
        {
            var url = new String(Encoding.UTF8.GetChars(Convert.FromBase64String(targetId)));
            var filename = url.Substring(url.LastIndexOf('\\') + 1);
            filename = "export-" + DateTime.Now.ToString("yyyy-MM-dd-HHmm") + filename.Substring(filename.Length - 4);
            context.Response.ContentType = "application/octet-stream";
            context.Response.AppendHeader("Content-Disposition", String.Format("attachment;filename={0}", filename));
            var data = File.ReadAllBytes(url);
            File.Delete(url);
            context.Response.BinaryWrite(data);
        }
        catch (Exception ex)
        {
            context.Response.Clear();
            context.Response.Write("Error occurred: " + ex.Message);
            context.Response.ContentType = "text/plain";
            context.Response.End();
        }
    }
    public bool IsReusable { get { return false; } }
}

来源：https://stackoverflow.com/questions/6543673/how-to-download-open-the-file-that-i-retrive-by-server-path