ASP.NET MVC - conditionally open PDF / image in new tab
Here I have a filtering report page where I can filter some information for the report (RDLC, returning a PDF or image file). Today this page returns files always in a new tab because I use this:
@using (Html.BeginForm("Report", "ReportController", FormMethod.Post, new { target = "_blank" }))
and my ReportController returns a FileContentResult like below:
return File(renderedBytes, mimeType, fileName + "." + fileNameExtension);
However, this page has some server side validation and the postback always happens on the newly created tab and not the original where the submit button was clicked. Is there a way to return a new page (target = "_blank", generated PDF or image) only if the ModelState has no errors? I want to use the report filtering page if there are errors.
Thanks in advance.
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You can split report generation into two separate steps.
1. Extend your view model with new Target, Action properties (this will help you dynamically change form attributes).
[HttpGet]
function ActionResult Report()
{
var model = new ReportViewModel{ Target = "_self", DownloadFile = false, Action = "Report" };
return View(model);
}
2.Inject your model and set these properties to new values in case of valid model state
[HttpPost]
function ActionResult Report(ReportViewModel model)
{
if (ModelState.IsValid)
{
model.DownloadFile = true;
model.Action = "DownloadReport";
model.Target = "_blank";
return View(model);
}
else
{
// server side error occurred
return View(model);
}
}
3.Use jquery to automatically execute the second form submission for the new target action
@using (Html.BeginForm(Model.Action, "ReportController", FormMethod.Post, new { target = Model.Target, id = "MyForm" }))
{
@Html.HiddenFor(m => m.Action);
@Html.HiddenFor(m => m.Target);
@if(Model.DownloadFile)
{
<script>$(document).ready(function () { $("#MyForm").submit(); }</script>
}
// other form elements
}
3. Submitting the second form:
[HttpPost]
function ActionResult DownloadReport(ReportViewModel model)
{
// generate file
return File(renderedBytes, mimeType, fileName + "." + fileNameExtension);
}
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