文件内容查看器在浏览器上使用asp.net

您将无法看到任何文件的内容，因为这将要求有关浏览器具有显示特定文件的插件。以MS项目文件、Corel绘图文件、Auto CAD等为例。浏览器不会显示这些文件，因为AFAIK，没有为这些文件提供插件，可以被浏览器用来嵌入一个查看器。

一般来说，浏览器会很高兴地显示pdf(如果安装了Acrobat Reader)、图像、TXT文件和其他一些文件。

因此，您可以执行以下操作来读取所有文件:

DirectoryInfo info = new DirectoryInfo("PhysicalPathToFiles");
GridView1.DataSource=info.GetFiles();
GridView1.DataBind();

并设置GrdiView1标记，仅绑定FileName属性和所需的其他所有内容。您可能希望在该列上构造一个超链接，以便在单击文件名时，根据文件类型要求用户下载/查看该文件。

假设您将所有文件绑定到Gridview，就像我上面解释的那样。有了这样一个GridViewColumn，应该允许用户点击任何文件并在浏览器中看到它。

<asp:HyperLinkColumn
                 HeaderText="File Name"
                 DataNavigateUrlField="Name"
                 DataNavigateUrlFormatString="UploadedFiles/{0}"
                 DataTextField="Name"
                 />

其中UploadedFiles是应用程序中保存这些文件的虚拟目录

为了允许用户查看内联文件，您需要将文件流式传输给用户并在header中设置一些值。

我们通常使用映射到"虚拟"页面(即Download.aspx)的HTTP处理程序来执行此操作，以便可以在弹出窗口中从客户端调用它，而不会影响调用页面。

此机制可用于下载或查看内联文件。

下面是在类的StreamFileToUser方法中实现的下载过程的描述:

如果调用者请求下载，则检查mime类型集合以确定文件是否包含受支持的mime类型，这意味着它有机会内联显示给用户。

如果找到mime类型，我们使用内联指令要求浏览器将文件显示给用户。如果浏览器不支持此mime类型的内联，则会提示用户下载。

如果没有找到mime类型，则直接发出下载命令。

打开IIS管理器，选择web服务器图标，双击mime类型图标，可以获得IIS内mime类型的完整列表(假设为7+)。

下面是一个HTTP处理程序类的例子:

public class DownloadRequestHandler : System.Web.IHttpHandler, System.Web.SessionState.IRequiresSessionState
{
    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
    /// <summary>
    /// This method is used to process the incoming request
    /// </summary>
    /// <param name="oContext"></param>
    /// <remarks></remarks>
    public void ProcessRequest(HttpContext oContext)
    {
        try
        {
            string sFileName = null;
            string sSourceFilePath = null;
            // Should add existence checking here
            sFileName = oContext.Request.QueryString["FileName"];
            // Assume that the files are stored in the relative directory Files. Should add existence checking here
            sSourceFilePath = System.IO.Path.Combine(oContext.Server.MapPath("Files"), sFileName);
            StreamFileToUser(GenerateStandardMimeList(), sSourceFilePath, sFileName, oContext.Response, false, false);
        }
        catch (System.Threading.ThreadAbortException theException)
        {
            // Do nothing
        }
        catch (Exception theException)
        {
            SendErrorToUser(oContext.Response, theException.Message);
        }
    }
    /// <summary>
    /// This method streams a file to a user
    /// </summary>
    /// <param name="cMimeTypes">The set of known mimetypes. This is only needed when the file is not being downloaded.</param>
    /// <param name="sFileName"></param>
    /// <param name="sFileNameForUser"></param>
    /// <param name="theResponse"></param>
    /// <param name="fDownload"></param>
    /// <returns></returns>
    /// <remarks></remarks>
    public bool StreamFileToUser(System.Collections.Generic.Dictionary<string, string> cMimeTypes, string sFileName, string sFileNameForUser, HttpResponse theResponse, bool fDownload = true, bool fOkToDeleteFile = false)
    {
        // Exceptions are handled by the caller
        bool fDontEndResponse = false;
        sFileNameForUser = CleanFileName(sFileNameForUser);
        // Ensure there is nothing else in the response
        try
        {
            try
            {
                // Remove what other controls may have been put on the page
                theResponse.ClearContent();
                // Clear any headers
                theResponse.ClearHeaders();
            }
            catch (System.Web.HttpException theException)
            {
                // Ignore this exception, which could occur if there were no HTTP headers in the response
            }
            bool fFoundIt = false;
            if (!fDownload)
            {
                string sExtension = null;
                sExtension = System.IO.Path.GetExtension(sFileNameForUser);
                if (!(string.IsNullOrEmpty(sExtension)))
                {
                    sExtension = sExtension.Replace(".", "");
                    if (cMimeTypes.ContainsKey(sExtension))
                    {
                        theResponse.ContentType = cMimeTypes[sExtension];
                        theResponse.AddHeader("Content-Disposition", "inline; filename=" + sFileNameForUser);
                        fFoundIt = true;
                    }
                }
            }
            if (!fFoundIt)
            {
                theResponse.ContentType = "application/octet-stream";
                theResponse.AddHeader("Content-Disposition", "attachment; filename=" + sFileNameForUser);
            }
            theResponse.TransmitFile(sFileName);
            // Ensure the file is properly flushed to the user
            theResponse.Flush();
        }
        finally
        {
            // If the caller wants, delete the file before the response is terminated
            if (fOkToDeleteFile)
            {
                System.IO.File.Delete(sFileName);
            }
        }
        // Ensure the response is closed
        theResponse.Close();
        if (!fDontEndResponse)
        {
            try
            {
                theResponse.End();
            }
            catch
            {
            }
        }
        return true;
    }
    /// <summary>
    /// This method generates a standard list of extension to content-disposition tags
    /// The key for each item is the file extension without the leading period. The value 
    /// is the content-disposition.
    /// </summary>
    /// <returns></returns>
    /// <remarks></remarks>
    public System.Collections.Generic.Dictionary<string, string> GenerateStandardMimeList()
    {
        // Exceptions are handled by the caller.
        System.Collections.Generic.Dictionary<string, string> cItems = new Dictionary<string, string>();
        cItems.Add("jpeg", "image/jpeg");
        cItems.Add("jpg", "image/jpeg");
        cItems.Add("pdf", "application/pdf");
        cItems.Add("csv", "application/vnd.ms-excel");
        cItems.Add("doc", "application/msword");
        cItems.Add("docx", "application/vnd.ms-word.document.12");
        cItems.Add("xls", "application/vnd.ms-excel");
        cItems.Add("xlsx", "application/vnd.ms-excel.12");
        return cItems;
    }
    /// <summary>
    /// This method removes all invalid characters from the specified file name.
    /// Note that ONLY the file name should be passed, not the directory name.
    /// </summary>
    /// <param name="sFileName"></param>
    /// <returns></returns>
    /// <remarks></remarks>
    public string CleanFileName(string sFileName)
    {
        // Exceptions are handled by the caller
        // If there are any invalid characters in the file name
        if (sFileName.IndexOfAny(System.IO.Path.GetInvalidFileNameChars()) >= 0)
        {
            // Strip them out (split to remove the characters, then rejoin the pieces into one string)
            return string.Join("", sFileName.Split(System.IO.Path.GetInvalidFileNameChars()));
        }
        else
        {
            return sFileName;
        }
    }
    public void SendErrorToUser(HttpResponse theResponse, string sError)
    {
        // Note that errors are handled by the caller
        sError = "<script>alert('"" + sError.Replace("'"", "").Replace(Environment.NewLine, "''n") + "'");</script>";
        // Ensure there is nothing else in the response
        theResponse.Clear();
        theResponse.Write(sError);
        theResponse.Flush();
    }
}

在你的网页。配置，将以下行添加到httphandlers部分，并根据需要替换名称空间:

    <add path="download.aspx" verb="*" type="MyWebApp.DownloadRequestHandler, MyWebApp" validate="false" />

那么你的下载请求是:

download.aspx?FileName=thefile.pdf

和上面的代码假设文件存储在网站的files子目录中