Develop Reference

Looking for ideas to solve issue with WEBAPI style controller in ASP.NET site

I was tasked with implementing a file upload utility to our existing ASP.NET corporate site. This 3rd party utility (Uppy.js) works great but it calls a controller to upload a file and I have a traditional ASP.NET site. So I added a controller to our ASP.NET Website application and created a JavaScript function which POSTs an image or PDF to the end point /api/docfile.
This code works without issue locally in my DEV environment, however, when I load to a QA box I get an Internal Server Error (500) and I am at a loss as to why. This is what I am hoping someone might have an idea that can help.
JavaScript
var uppy = Uppy.Core({
locale: localeLib,
restrictions: {
maxFileSize: 20971520,
maxNumberOfFiles: 5,
allowedFileTypes: ['application/pdf', 'image/jpeg', 'image/jpg']}
})
.use(Uppy.Dashboard, {
inline: true,
target: '#drag-drop-area',
replaceTargetContent: true,
showProgressDetails: true,
note: uploadMsg,
proudlyDisplayPoweredByUppy: false,
width: "auto",
browserBackButtonClose: true
})
.use(Uppy.ProgressBar, {
target: Uppy.Dashboard,
hideAfterFinish: false
})
.use(Uppy.XHRUpload, {
fieldName: 'document_contents',
endpoint: 'api/docfile'
})})
ASP.NET Controller called from Uppy.js function above
[Route("post")]
public HttpStatusCode Post()
{
HttpResponseMessage result = null;
var httpRequest = HttpContext.Current.Request;
if (httpRequest.Files.Count > 0)
{
var docfiles = new List<string>();
foreach (string file in httpRequest.Files)
{
var postedFile = httpRequest.Files[file];
var filePath = ConfigurationManager.AppSettings["FileShare"] + postedFile.FileName;
postedFile.SaveAs(filePath);
docfiles.Add(filePath);
}
result = Request.CreateResponse(HttpStatusCode.Created, docfiles);
}
return result.StatusCode;
}
Global.asax file to allow a Controller to be used within a traditional ASP.NET Website (not WebAPI)
public class Global : HttpApplication
{
internal static HttpClient httpClientInstance;
protected void Application_Start()
{
RouteTable.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = System.Web.Http.RouteParameter.Optional
});
}
}

ASP.NET MVC 3 routes with backbone views

I'm pretty new to the web and am trying to understand what happens on our current project. For one of our single page apps, the Controller returns a single view for the whole area.
[HttpGet]
[Url("admin")]
public virtual ActionResult Index()
{
return View(Admin);
}
In the actual Admin.cshtml, we create a backbone router that gets initialized for that section of the page and has the different views for that single page app section. My question is, I want to create an action on the route
admin/import/upload
How would that look? I don't want to actually return a View, but I want to call a function when that route gets hit to validate the uploaded file and return JSON info about the file.

You need to define a model that has a property for your uploaded file like so, it should be of type HttpPostedFileBase.
public class UploadModel
{
[Required(ErrorMessage="Please choose a file to upload.")]
public HttpPostedFileBase Photo { get; set; }
}
Then you need to make your action that accepts the specified model and returns JavaScript instead of View.
public ActionResult Upload(UploadModel model)
{
//only continue if the model is valid (i.e. all the required fields have been set)
if (ModelState.IsValid)
{
string json = "";//build your JSON here
//return the JSON as a javascript response (with the correct headers, etc)
return JavaScript(json);
}
return View(model);
}

(function() {
window.App = {
Router: {}
View: {}
};
App.Router = Backbone.Router.extend({
routes: {
'*AreaName/admin/import/upload': 'upload'
},
upload: function() {
var upload= new App.View.upload();
},
});
$(document).ready(function() {
window.routes = new App.Router;
Backbone.history.start({ pushState: true });
});
})();

How to call a C# function from JavaScript?

I want to call CsharpFunction, a C# function in code-behind, from JavaScript. I tried the code below but whether the JavaScript condition is True or False, CsharpFunction was called regardless!
JavaScript code:
if (Javascriptcondition > 0) {
<%CsharpFunction();%>
}
C# code behind:
protected void CsharpFunction()
{
// Notification.show();
}
How do I call a C# function from JavaScript?

You can use a Web Method and Ajax:
<script type="text/javascript"> //Default.aspx
function DeleteKartItems() {
$.ajax({
type: "POST",
url: 'Default.aspx/DeleteItem',
data: "",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
$("#divResult").html("success");
},
error: function (e) {
$("#divResult").html("Something Wrong.");
}
});
}
</script>
[WebMethod] //Default.aspx.cs
public static void DeleteItem()
{
//Your Logic
}

.CS File
namespace Csharp
{
public void CsharpFunction()
{
//Code;
}
}
JS code:
function JSFunction() {
<%#ProjectName.Csharp.CsharpFunction()%> ;
}
Note :in JS Function when call your CS page function.... first name of project then name of name space of CS page then function name

A modern approach is to use ASP.NET Web API 2 (server-side) with jQuery Ajax (client-side).
Like page methods and ASMX web methods, Web API allows you to write C# code in ASP.NET which can be called from a browser or from anywhere, really!
Here is an example Web API controller, which exposes API methods allowing clients to retrieve details about 1 or all products (in the real world, products would likely be loaded from a database):
public class ProductsController : ApiController
{
Product[] products = new Product[]
{
new Product { Id = 1, Name = "Tomato Soup", Category = "Groceries", Price = 1 },
new Product { Id = 2, Name = "Yo-yo", Category = "Toys", Price = 3.75M },
new Product { Id = 3, Name = "Hammer", Category = "Hardware", Price = 16.99M }
};
[Route("api/products")]
[HttpGet]
public IEnumerable<Product> GetAllProducts()
{
return products;
}
[Route("api/product/{id}")]
[HttpGet]
public IHttpActionResult GetProduct(int id)
{
var product = products.FirstOrDefault((p) => p.Id == id);
if (product == null)
{
return NotFound();
}
return Ok(product);
}
}
The controller uses this example model class:
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public string Category { get; set; }
public decimal Price { get; set; }
}
Example jQuery Ajax call to get and iterate over a list of products:
$(document).ready(function () {
// Send an AJAX request
$.getJSON("/api/products")
.done(function (data) {
// On success, 'data' contains a list of products.
$.each(data, function (key, item) {
// Add a list item for the product.
$('<li>', { text: formatItem(item) }).appendTo($('#products'));
});
});
});
Not only does this allow you to easily create a modern Web API, you can if you need to get really professional and document it too, using ASP.NET Web API Help Pages and/or Swashbuckle.
Web API can be retro-fitted (added) to an existing ASP.NET Web Forms project. In that case you will need to add routing instructions into the Application_Start method in the file Global.asax:
RouteTable.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = System.Web.Http.RouteParameter.Optional }
);
Documentation
Tutorial: Getting Started with ASP.NET Web API 2 (C#)
Tutorial for those with legacy sites: Using Web API with ASP.NET Web Forms
MSDN: ASP.NET Web API 2

Use Blazor
http://learn-blazor.com/architecture/interop/
Here's the C#:
namespace BlazorDemo.Client
{
public static class MyCSharpFunctions
{
public static void CsharpFunction()
{
// Notification.show();
}
}
}
Then the Javascript:
const CsharpFunction = Blazor.platform.findMethod(
"BlazorDemo.Client",
"BlazorDemo.Client",
"MyCSharpFunctions",
"CsharpFunction"
);
if (Javascriptcondition > 0) {
Blazor.platform.callMethod(CsharpFunction, null)
}

Server-side functions are on the server-side, client-side functions reside on the client.
What you can do is you have to set hidden form variable and submit the form, then on page use Page_Load handler you can access value of variable and call the server method.
More info can be found here
and here

If you're meaning to make a server call from the client, you should use Ajax - look at something like Jquery and use $.Ajax() or $.getJson() to call the server function, depending on what kind of return you're after or action you want to execute.

You can't. Javascript runs client side, C# runs server side.
In fact, your server will run all the C# code, generating Javascript. The Javascript then, is run in the browser. As said in the comments, the compiler doesn't know Javascript.
To call the functionality on your server, you'll have to use techniques such as AJAX, as said in the other answers.

what is the return statement in server side for Kendo UI uploader

I am using Kendo UI upload for uploading single/multiple files.
I have implemented it like,
<input name="file" id="files" type="file" />
<script type="text/javascript">
$(document).ready(function () {
$("#files").kendoUpload({
async: {
saveUrl: "/NewFile/upload",
autoUpload: false,
},
});
});
</script>
In the controller,I gave like,
public ActionResult upload(HttpPostedFileBase file)
{
//Code for saving in DB
return???
}
I am able to save record in database,but It is displaying like,"Retry" and showing not successfully uploaded.so Can you tell me what is the return statement I have to use to display proper status upload.

You should return empty response:
public ActionResult upload(HttpPostedFileBase file)
{
// Code to save in DB
// Return an empty string to signify success
return Content("");
}

In the controller,I gave like
public ActionResult upload(HttpPostedFileBase file)
{
var s = new { st = "successfully uploaded" };
//Code for save in DB
return json(s,JsonRequestBehavior.AllowGet);
}

ASP.net MVC put complex data (array) to controller method

I'm porting an ASP.net Web Forms application to MVC.
The application uses AJAX, by means of Ajax-enabled WCF Web service and asp:ScriptManager. I send an array of objects for service, it handles it just great. Code example,
<script type="text/javascript">
$().ready(function () {
var ser = new Services.TasksService();
$('#tasks').tasksgrid(
'newTaskName',
'createTask',
'submitData',
loadData,
submitData,
deleteData
);
function loadData(callback) {
return ser.GetAllTasks(callback, null, null);
}
function submitData(data, callback) {
return ser.Submit(data, callback, null, null);
}
function deleteData(data, callback) {
return ser.Delete(data, callback, null, null);
}
}
);
</script>
WCF service side code:
[ServiceContract(Namespace = "Services")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class TasksService
{
[OperationContract]
public IList<Task> GetAllTasks()
{
//Code..
}
[OperationContract]
public void Submit(IList<Task> tasks)
{
//Code..
}
[OperationContract]
public void Delete(IList<Task> tasks)
{
//Code..
}
}
The Submit/Delete method, recieves Array of Tasks objects. I create those array dynamically in client side script and just put it to corresponding Services.TasksService (no $.toJSON or JSON.stringly call, nothing like that). WCF infrastucture handles it greacefully and I always get a correct object on server.
Now, I'm getting rid of WCF service and try to do the same with Controller class. GetAllTasks were fine.. but I totally missed with 'recieving' data methods.
In controller I have,
[HttpPost]
public JsonResult Submit(IList<Task> tasks)
{
On client,
function submitData(data, callback) {
$.post('/Tasks/Submit', JSON.stringify(data), callback, 'json');
}
But anything I tried, I always recieve null as tasks object (so, data is not binded).
I've seen Phil Haack post on that, but would like to avoid using of any additional assemblies, if possible.

MVC needs to be told what variable on the server side to bind the data to. In your example you could do the following:
function submitData(data, callback) {
$.post('/Tasks/Submit', { tasks: data }, callback, 'json');
}

Look here http://theycallmemrjames.blogspot.com/2010/05/aspnet-mvc-and-jquery-part-4-advanced.html