I finally got a way to do this.
Actually rotativa's method "return new ViewAsPdf(model)" returns HttpResponseStream. Where we can hardly do something. But we can modify/alter the response once the action get executed by using custom attribute. We can override OnResultExecuted() method of action filter.
Controller's action
[HttpGet]
[ActionDownload] //here a custom action filter added
public ActionResult DownloadDocument()
{
var htmlContent = "<h1>sachin Kumar</hi>";
var model = new PdfInfo {FtContent = htmlContent, FtName = "Populate Form"};
return new ViewAsPdf(model);
}
Custom Action filter:
public class ActionDownloadAttribute : ActionFilterAttribute
{
public override void OnResultExecuted(ResultExecutedContext filterContext)
{
//Add content-disposition header to response so that browser understand to download as an attachment.
filterContext.HttpContext.Response.AddHeader("content-disposition", "attachment; filename=" + "Report.pdf");
base.OnResultExecuted(filterContext);
}
}