我查看了许多在线资源并构建了我的脚本，但它似乎仍然没有给我这个文件。它只是加载页面“client-home2.aspx / downloadAttachment”而不是执行代码并传递文件。
这是我背后的代码：
[WebMethod]
public void downloadAttachment(string id)
{
DbProviderFactory dbf = DbProviderFactories.GetFactory();
using (IDbConnection con = dbf.CreateConnection())
{
string sSQL;
sSQL = "select top 1 " + ControlChars.CrLf
+ " FILENAME, FILE_MIME_TYPE, ATTACHMENT" + ControlChars.CrLf
+ " from vwATTACHMENTS_CONTENT" + ControlChars.CrLf
+ " where 1 = 1 " + ControlChars.CrLf;
//Debug.Print(sSQL);
using (IDbCommand cmd = con.CreateCommand())
{
cmd.CommandText = sSQL;
Sql.AppendParameter(cmd, id.ToString(), "ATTACHMENT_ID");
cmd.CommandText += " order by DATE_ENTERED desc" + ControlChars.CrLf;
using (DbDataAdapter da = dbf.CreateDataAdapter())
{
((IDbDataAdapter)da).SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
da.Fill(dt);
if (dt.Rows.Count > 0)
{
foreach (DataRow r in dt.Rows)
{
string name = (string)r["FILENAME"];
string contentType = (string)r["FILE_MIME_TYPE"];
Byte[] data = (Byte[])r["ATTACHMENT"];
// Send the file to the browser
Response.AddHeader("Content-type", contentType);
Response.AddHeader("Content-Disposition", "attachment; filename=" + name);
Response.BinaryWrite(data);
Response.Flush();
Response.End();
}
}
else
{
}
}
}
}
}
}
这是我的jQuery：
$('.attachmentLink').click(function () {
var id = $(this).attr('id');
/*
$.ajax({
type: "POST",
url: "client-home2.aspx/downloadAttachment",
data: '{id:\'' + id + '\'}',
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
//alert(msg.d);
}
});
*/
$.download('client-home2.aspx/downloadAttachment', 'id=' + id);
return false;
});
我正在使用此功能http://filamentgroup.com/lab/jquery_plugin_for_requesting_ajax_like_file_downloads/
问题是，它永远不会给我文件;它只是导航到client-home2.aspx/downloadAttachment。
如何解决此问题以便我可以下载文件？
谢谢。
答案 0 :(得分：2)
每个WebMethod调用只能发送一个HTTP响应。这意味着一次只能有一个文件。使用Response.End()阻止其他任何东西返回到Web浏览器，并且第二次通过foreach循环可能会抛出异常。解决这个问题的唯一方法是从你的jQuery代码中调用WebMethod 20次，并且如果查询中有多个结果，则每次都要知道要返回哪个文件。即使这可能也行不通。
但我怀疑你真的打算让ID字段只产生一条记录。在这种情况下，您需要了解两件事。第一个是当您更改CommandText属性时，SqlCommand类型会重置它的Parameters集合。因此，您需要在添加ID参数之前完成创建整个sql字符串文本。第二个是你的ID参数现在甚至都不重要，因为你的sql代码从不引用那个参数。
我对发布这段代码犹豫不决，因为还有其他一些东西也可能出错，但这应该是对你所拥有的东西的改进。请注意，我最终也做了同样的工作，但是少了很少的代码：
[WebMethod]
public void downloadAttachment(string id)
{
string SQL =
"select top 1 FILENAME, FILE_MIME_TYPE, ATTACHMENT" + ControlChars.CrLf
+ " FROM vwATTACHMENTS_CONTENT" + ControlChars.CrLf
+ " where ID = @ATTACHMENT_ID" + ControlChars.CrLf
+ " order by DATE_ENTERED desc";
//Debug.Print(SQL);
DbProviderFactory dbf = DbProviderFactories.GetFactory();
using (IDbConnection con = dbf.CreateConnection())
using (IDbCommand cmd = con.CreateCommand())
{
cmd.CommandText = SQL;
Sql.AppendParameter(cmd, id, "ATTACHMENT_ID");
using (IDataReader rdr = cmd.ExecuteReader())
{
if (rdr.Read())
{
// Send the file to the browser
Response.AddHeader("Content-type", r["FILE_MIME_TYPE"].ToString());
Response.AddHeader("Content-Disposition", "attachment; filename=" + r["FILENAME"].ToString());
Response.BinaryWrite((Byte[])r["ATTACHMENT"]);
Response.Flush();
Context.ApplicationInstance.CompleteRequest();
}
}
}
}
答案 1 :(得分：0)
以下是我过去的做法，但我的方式不同：
查看：
foreach (var file in foo.Uploads)
{
<tr>
<td>@Html.ActionLink(file.Filename ?? "(no filename)", "Download", "Upload", new { id = file.UploadId }, null)</td>
</tr>
}
我的UploadConroller中的代码：
public ActionResult Download(Guid id)
{
var upload = this.GetUpload(id);
if (upload == null)
{
return NotFound();
}
return File(upload.Data, upload.ContentType, upload.Filename);
}
private Upload GetUpload(Guid id)
{
return (from u in this.DB.Uploads
where u.UploadId == id
select u).SingleOrDefault();
}
随意对货物进行崇拜，这非常简单。
答案 2 :(得分：0)
我明白了。我必须创建一个单独的文件，因为标题已经被发送。因此，我的单独文件名为“downloadAttachment”，如下所示：
using System;
using System.Data;
using System.Data.Common;
using System.Configuration;
using System.Drawing;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Xml;
using System.Globalization;
using System.Threading;
using System.Diagnostics;
using System.Net;
using System.Net.Mail;
using System.Data.SqlClient;
using System.Web.Services;
using System.Text;
using System.Web.Script.Services;
using System.Text.RegularExpressions;
using System.IO;
namespace SplendidCRM.WebForms
{
public partial class downloadAttachment : System.Web.UI.Page
{
string HostedSite;
protected DataView vwMain;
protected void Page_Load(object sender, EventArgs e)
{
if (Sql.IsEmptyGuid(Security.USER_ID))
Response.Redirect("~/Webforms/client-login.aspx");
HostedSite = Sql.ToString(HttpContext.Current.Application["Config.hostedsite"]);
string id = Request.QueryString["ID"].ToString();
DbProviderFactory dbf = DbProviderFactories.GetFactory();
using (IDbConnection con = dbf.CreateConnection())
{
string sSQL;
sSQL = "select top 1 " + ControlChars.CrLf
+ " FILENAME, FILE_MIME_TYPE, ATTACHMENT" + ControlChars.CrLf
+ " from vwATTACHMENTS_CONTENT" + ControlChars.CrLf
+ " where 1 = 1 " + ControlChars.CrLf;
//Debug.Print(sSQL);
using (IDbCommand cmd = con.CreateCommand())
{
cmd.CommandText = sSQL;
Sql.AppendParameter(cmd, id.ToString(), "ATTACHMENT_ID");
cmd.CommandText += " order by DATE_ENTERED desc" + ControlChars.CrLf;
using (DbDataAdapter da = dbf.CreateDataAdapter())
{
((IDbDataAdapter)da).SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
da.Fill(dt);
if (dt.Rows.Count > 0)
{
foreach (DataRow r in dt.Rows)
{
string name = (string)r["FILENAME"];
string contentType = (string)r["FILE_MIME_TYPE"];
Byte[] data = (Byte[])r["ATTACHMENT"];
// Send the file to the browser
Response.AddHeader("Content-type", contentType);
Response.AddHeader("Content-Disposition", "attachment; filename=" + MakeValidFileName(name));
Response.BinaryWrite(data);
Response.Flush();
Response.End();
}
}
else
{
}
}
}
}
}
}
public static string MakeValidFileName(string name)
{
string invalidChars = Regex.Escape(new string(System.IO.Path.GetInvalidFileNameChars()));
string invalidReStr = string.Format(@"[{0}]+", invalidChars);
string replace = Regex.Replace(name, invalidReStr, "_").Replace(";", "").Replace(",", "");
return replace;
}
}
}