使用AJAX调用在javascript中下载文件

问题描述

这是我的java脚本代码，用于从按钮点击的数据库中下载文件，当按钮点击此功能调用。使用ajax调用我已经移动到处理程序。

This is my java script code for downloading the file from database on button click, when the button clicks this function calls. using ajax call i have moved to handler.

function DownloadDocument() {
    var CurrentUserEmpId = CurrentSelectedUser;
    Ext.Ajax.request({
        url: "UploadAttachment.ashx?mode=DownloadDocument&EmployeeId=" + CurrentUserEmpId,
        success: function (response) {
            var data = response.responseText;
        },
        failure: function (form, action) {
        }
    });
}

这里是处理程序页面，我有文件的字节为 byte [] buffer 。这里的问题是下载不起作用。我不知道这个问题，因为Iam是初学者。请帮助，谢谢。

Here comes the handler page, I have got bytes of my file to byte[] buffer. The problem here is download not working. I could't figure out the problem, since Iam a beginner. Please help with this, Thankyou.

case "DownloadDocument":

            WebClient web = new WebClient();
            try
            {
                byte[] buffer;

                var query2 = @"select LLD_Decleration_doc from (select  instance, Employee_id, lld_Decleration_doc, ROW_NUMBER() OVER(PARTITION BY Employee_id ORDER BY Update_Date DESC) Latest from [EManager].[dbo].[tax_benefit_declaration]) a where latest = 1 And Employee_id = @EmployeeId";

                using (SqlConnection con = new SqlConnection(db.ConnectionString))
                using (SqlCommand cmd = new SqlCommand(query2, con))
                {
                    SqlParameter param = cmd.Parameters.Add("@EmployeeId", SqlDbType.Int);
                    param.Value = EmployeeId;
                    con.Open();

                    buffer = (byte[])cmd.ExecuteScalar();
                    con.Close();
                }

                HttpResponse response = HttpContext.Current.Response;
                response.Clear();
                response.ClearContent();
                response.ClearHeaders();
                response.Buffer = true;
                response.ContentType = "APPLICATION/OCTET-STREAM";
                String Header = "Attachment; Filename=NewFile";
                response.AppendHeader("Content-Disposition", Header);
                context.Response.BinaryWrite(buffer);
                response.End();
            }
            catch { }
            break;
    }

推荐答案

多次说您可以通过Ajax调用来执行此操作。

This is something that it was said many times. You cant do this with Ajax call.

您可以通过调用隐藏的 iframe 来实现此目的：

You can achive this by invoke hidden iframe for example:

                var body = Ext.getBody();
                var comp = body.getById('hiddenform-iframe-download');
                if (!Ext.isEmpty(comp)) {
                    comp.remove();
                }
                body.createChild({
                    tag: 'iframe',
                    cls: 'x-hidden',
                    id: 'hiddenform-iframe-download',
                    name: 'iframe',
                    src: "yourContextToDownload?param1="+something
                });

这篇关于使用AJAX调用在javascript中下载文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！