How to download a file through ajax request in asp

问题:

Below is my code :

ActionResult DownloadAttachment(student st)
{          
    var file = db.EmailAttachmentReceived.FirstOrDefault(x => x.LisaId == st.Lisaid);

    byte[] fileBytes = System.IO.File.ReadAllBytes(file.Filepath);
    return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, file.Filename);                 
}

This is the script which i'm using

$(function () {
    $("#DownloadAttachment").click(function () {
        $.ajax({
            url: '@Url.Action("DownloadAttachment", "PostDetail")',
            contentType: 'application/json; charset=utf-8',
            datatype: 'json',
            type: "GET",
            success: function () {
                alert("sucess");
            }
        });    
    });
});      

How to return the file for download pursing above code?

回答1:

Please, try this in ajax success

success: function () {
    window.location = '@Url.Action("DownloadAttachment", "PostDetail")';
}

Updated answer:

public ActionResult DownloadAttachment(int studentId)
{          
    // Find user by passed id
    // Student student = db.Students.FirstOrDefault(s => s.Id == studentId);

    var file = db.EmailAttachmentReceived.FirstOrDefault(x => x.LisaId == studentId);

    byte[] fileBytes = System.IO.File.ReadAllBytes(file.Filepath);

    return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, file.Filename);                       

}

Ajax request:

$(function () {
        $("#DownloadAttachment").click(function () {
            $.ajax(
            {
                url: '@Url.Action("DownloadAttachment", "PostDetail")',
                contentType: 'application/json; charset=utf-8',
                datatype: 'json',
                data: {
                    studentId: 123
                },
                type: "GET",
                success: function () {
                    window.location = '@Url.Action("DownloadAttachment", "PostDetail", new { studentId = 123 })';
                }
            });

        });
    });

回答2:

I think there is no need of Ajax call you can do simply using hyperlink as below example.

View Code

<a href="@Url.Action("DownloadAttachment", "PostDetail", new { studentId = 123 })">Download Form</a>

Controller Method

public ActionResult DownloadAttachment(int studentId)
{          
    // Find user by passed id
    var file = db.EmailAttachmentReceived.FirstOrDefault(x => x.LisaId == studentId);    
    byte[] fileBytes = System.IO.File.ReadAllBytes(file.Filepath);    
    return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, file.Filename);                           
}

回答3:

Below method would helps calling action from Ajax request from jQuery dialog window and it executes the action and can be closed dialog window as soon the action return success result

Controller

    [HttpGet]
    public ActionResult DownloadCampaign(string filePath, string mode)
    {
        string contentType = string.Empty;
        var sDocument = filePath;
        if (!System.IO.File.Exists(sDocument))
        {
            return HttpNotFound();
        }

        if (mode == "action")
            return Json(new {fileName = filePath}, JsonRequestBehavior.AllowGet);

        if (sDocument.Contains(".pdf"))
        {
            contentType = "application/pdf";
        }
        else if (sDocument.Contains(".docx"))
        {
            contentType = "application/docx";
        }
        else if (sDocument.Contains(".xls"))
        {
            contentType = "application/xlsx";
        }

        return File(sDocument, contentType, sDocument);
    }

JQuery - Ajax Request

$(document)
    .ready(function() {
        $("#btnDownload").click(function () {
            var file = $("#FilePath").val();
            $.ajax({
                url: '@Url.Action("DownloadCampaign", "FileList")',
                data: { filePath: file, mode:'action' },
                method: 'GET',
                dataType: 'json',
                //contentType: 'application/json; charset=utf-8',

                success: function(data) {
                    @*window.location = '@Url.RouteUrl("DownloadCampaign", "FileList", new { filePath = data1.fileName })';*@
                    window.location.href = "@Url.RouteUrl(new
                    { Controller = "FileList", Action = "DownloadCampaign" })/?filePath=" + data.fileName + "&mode=download";
                    $("#downloadFile_dialog").dialog("close");
                },
                error: function (req, status, errorObj) {
                    alert("Error");
                }
            });

        });
});

Please reach out to me if you need more information about this.

回答4:

public FileResult DownloadGeneralDocs(string docName)
    {
        string fileName = docName+".pdf";           
        var path = _globalWebSettings.Value.DownloadGeneralDocsPath;
        string filePath = "";
        if (fileName!="")
        {
            filePath = (_env.WebRootPath + string.Format("{0}{1}",path, fileName));
        }
        FileInfo file1 = new FileInfo(filePath);            
        byte[] fileBytes = System.IO.File.ReadAllBytes(file1.FullName);
        return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, fileName);            
    }

view.cshtml:
<script>
$(document).ready(function () {
    $("#docTable tbody tr td button").click(function (e) {
        var docName = $(this).closest("tr").find(".document_td_data").text();
        $.ajax({
            url: '@Url.Action("DownloadGeneralDocs", "Documents")',                    
                dataType: "html",
                cache:false,
                data: { 'docName': docName },
                success: function (data) {                     
                    window.location.href = "@Url.RouteUrl(new
                { Controller = "Documents", Action = "DownloadGeneralDocs" })/?docName=" + docName ;

                },
                error: function (err, response) {
                    console.log(err, response);
                    alert(err, response.responseText);
                }
            })

    });
});