How to implement file download with AJAX and MVC

Question

I would like to provide a file download operation by using the jQuery AJAX call with some params under MVC

Example

(javascript)
function DoDownload(startDate) {

  $.ajax({ 
     url:"controller/GetFile/",
     data: {startDate:startDate}
     ...
  });

}

C# Controller Code

 public void GetFile(string startDate) {

  var results = doQueryWith(startDate);

   // Create file based on results
   ....
   // How do I tell the server to make this a file download??
 }

I typically would just make my file download a link such as:

<a h r e f="mycontroller/getfile/1"/>Download</a>

but in the case above the date will be dynamic.

If I don't use ajax, what would be a preferred way to pass in the params to the MVC controller using javascript?

Example:

window.location  = "mycontroller/GetFile/" + $("#fromDate").val();

assuming the date is 12-25-2012

Would this produce

mycontroller/GetFile/12/25/2012

would MVC treat this as three params?

Answer 1

You can use the File method of controller class to return a file back to the browser.

The below sample returns a pdf file.

public ActionResult GetFile(int id)
{
  var fileInfo=repositary.GetFileDedetails(id);
  var byteArrayOFFile=fileInfo.FileContentAsByteArray();
  return File(byteArrayOFFile,"application/pdf","yourFriendlyName.pdf");
}

Assuming repositary.GetFileDedetails method returns the details of the file from the id.

You may also return the file from a physical location(a path) or a stream. Check all the overloads of the File method and use appropriate one.

This has nothing to do with ajax. this is normal GET request over a browser.