I have a WP8 Pivot application which contains a Model that is meant to automatically bind against the View/Page.xaml. This is done by the auto-generated NotfifyPropertyChanged code which I have assigned to all of the properties that are spat out on to the page.
The problem as I see it is when the application is installed for the first time, the Model is obviously empty as the application is completely fresh. At this point, I call a web service which successfully retrieves data. Once retrieved, I save the data and assign the data to the Model.
Although I assign the data to the model, the View doesn't update itself. I also noticed that the NotifyPropertyChanged code doesn't fire when doing:
App.ViewModel.Signs = results.Signs
The code for the Model looks like this:
public int ID
{
get { return _id; }
set
{
if (value != _id)
{
_id = value;
NotifyPropertyChanged("ID");
}
}
}
The rest of the properties have the same notion, i.e. NotifyPropertyChanged("objectName");.
When I relaunch the application, the information on the screen successfully appears. It is only when the application fires from beginning or when the user manually asks for the latest data that it fails to update the View/Page.xaml.
Any ideas what I could do to fix this?
Maybe your NotifyPropertyChanged method is broken, or the Signs property does not call the method correctly.
Related
So, I wanted to create Post which can be subscribed by multiple users (Some kind of "looking for group to play with" site). And, after 4 hours passed, I want the author to be able to Upvote the participants, and after 24 Hours passed, the post should be automatically deleted from the database.
To make it, i've added a constructor to my Post.cs
public Post()
{
Subscribers = new List<ApplicationUser>(); //This part is not important
int timeToRateInt = Convert.ToInt32(AddedOn.Hour) + 4;
int timeToDeleteInt = Convert.ToInt32(AddedOn.Hour) + 24;
int now = Convert.ToInt32(DateTime.Now.Hour);
if(now>=timeToRateInt)
{
CanRate = true;
}
if(now>=timeToDeleteInt)
{
ToDelete = true;
}
}
The CanRate and ToDelete Are properties which i use later, but that is not that important, because program does not work properly at this point. (Later everything works perfectly fine if I manually change the database table data). So, CanRate and ToDelete Are still set to false. What is the issue? And if it should be assigned through controller, how to make sure it will change after user refreshes the site(Any page)?
Okay, so thing I've done is cutting the code and pasting it into my Action in Controller responsible for partial view. So this way everything works perfectly fine. I'll keep this question and answer here if anyone will have this issue.
I'm working on a ASP.NET Core MVC web app. I have a Model that includes a Dictionary. In one Action I'm adding a new element to it. Then I have other actions supposed to use the object from the Dictionary that was just added. But as it turns out - the dictionary is empty after the first action finished executing. Is there a way to fix it, so that the object is added permanently to the dictionary?
Update:
Well, the object I need to store is basically a virtual medical slide with a Deep Zoom tile generator. The flow is as follows: user click on the link to open the slide -> the ViewSlide Action creates the slide object -> then the OpenSeadragon viewer on the corresponding view sends requests to get XML metadata and JPEG tiles (256x256) on various Deep Zoom levels (based on mouse cursor position). So there's going to be a lot of requests for the tiles and I'm looking for a way to optimize the time needed to create them.
Here's a code snippet of the said actions:
[Route("[controller]/{slug}")]
public IActionResult ViewSlide(string slug)
{
try
{
var currentSlide = slideSet.Get(slug);
return View(currentSlide);
}
catch (Exception)
{
return RedirectToAction("Index");
}
}
public Slide Get(string slideUrl)
{
if (Slides.ContainsKey(slideUrl))
return Slides[slideUrl];
var pathToSlide = FilePaths[slideUrl];
Slides[slideUrl] = new Slide(pathToSlide);
return Slides[slideUrl];
}
[Produces("application/xml")]
[Route("[controller]/{slug}.dzi")]
public string Dzi(string slug)
{
try
{
return slideSet.Get(slug).DeepZoomGenerator.GetDziMetadataString(DEEPZOOM_FORMAT);
}
catch (Exception)
{
RedirectToAction("Index");
return "";
}
}
If you want to add the item permanently you can store it in:
Session (will not work in a web farm)
Cookie
Database
File
Here is how to store it in session:
// Place something in session
System.Web.HttpContext.Current.Session["whatever"] = value;
// Read from session
var whatever = System.Web.HttpContext.Current.Session["whatever"];
MVC also provides TempData which is basically a session which lives during the lifecycle of the trip on the server.
Depending on how you want to use this data, you have different options:
You can store it in the Session, Cookie, or TempData, if it's tied to the client, and no one else will need it. How long do you want to store the data? Cookies can be cleared, and you don't want to hold too much data in the Session either for a long time.
If the data does not belong to specific users, you can use a repository (e.g. singleton dictionary / database / HttpCache), but the first two needs to be cleaned regularly, while the HttpCache is not guaranteed to hold the data until it's requested.
And you could also rethink this concept, and stay stateless. This also makes it easier to scale your application horizontally, as well as adding HTTP cache, or even reverse proxy.
So basically it depends on what kind of data would you like to persist between action calls.
I am trying to move the content of a textbox on the from StudentRegistration to the form MyProfile by following a tutorial on YouTube. However when I try to reference the StudentRegitration Page in my code, I get the error that the type or namespace cannot be found.
In the tutorial I can see that in their code they have a namespace, however my website does not. Could anyone tell me what to do in order to be able to reference StudentRegistration without getting an error?
I should have stated that I have a website not a web app. I have found that websites do not have a default namespace. How would I go about accessing the StudentRegistration without referencing a namespace?
public partial class MyProfile : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (PreviousPage != null)
{
StudentRegistration LastPage = (StudentRegistration)Context.Handler;
lblEmail.Text = StudentRegistration.STextBoxEm;
}
}
}
Rather than answer your question directly, I'd like to point out another issue with your code that will probably prevent it from working. You should refer to the documentation on the PreviousPage property at: http://msdn.microsoft.com/en-us/library/system.web.ui.page.previouspage%28v=vs.110%29.aspx
It does NOT work like this:
user visits /StudentRegistration.aspx
user does stuff
user submits the form on /StudentRegistration.aspx
server redirects the user to /MyProfile.aspx
MyProfile class knows that PreviousPage = the class from /StudentRegistration.aspx
Instead, the description from the msdn reference page linked above stipulates that the PreviousPage property only works on this scenario:
user visits /StudentRegistration.aspx
user does some stuff
user submits form on /StudentRegistration.aspx
server transfers request to the MyProfile class
this does not mean that the url has changed to /MyProfile.aspx for the user, this means that the server is going to treat the current request to /StudentRegistration.aspx as if it were actually a request to /MyProfile.aspx
the user ends up seeing the result of what would normally be /MyProfile.aspx on /StudentRegistration.aspx
Now, your code may actually want that, but the fact that you have:
if (PreviousPage != null)
{
StudentRegistration LastPage = (StudentRegistration)Context.Handler;
// this should be
// StudentRegistration LastPage = (StudentRegistration)PreviousPage;
}
makes me think that you have misinterpreted the somewhat misleadingly named PreviousPage property. For a sample of how to persist state across multiple page loads in .NET, I would recommend reading up on SessionState. It has a somewhat complicated name, but does more of what you would want in this scenario:
http://msdn.microsoft.com/en-us/library/ms178581%28v=vs.100%29.aspx
An added bonus is that you do not need to reference one class from another, so you fix your current bug later on. Additionally, even if you did resolve your potential namespace error, the issue that I outlined earlier will cause the value of the text field to be blank if your code is working as I suspect.
You are sending data from a source to a target - e.g. StudentRegistration -> MyProfile
You have options because at the end of the day, it is HTTP. Aside from "persistence" (Session), and the tutorial you are following, a "simpler" way is to use ButtonPostBackUrl.
All it means is that you are POSTing data to the target page. The target page (MyProfile) will have to validate and parse the posted data (Request.Form). This way you don't have to manage things like Session state.
I am trying to get a listview selected item to work. I am trying to see if I can pass the selected value to a wcf and query the database from a selected county to a town. I am just wondering how I can do this?
Here is my onitem click event that I am building at the minute:
public void OnItemClick(AdapterView parent, View view, int position, long id)
{
var selectedValue = parent.GetItemAtPosition(position);
var Intent = new Intent(this, typeof(SelectLocationActivity));
// selectedValue should already be a string but...
Intent.PutExtra("Name", selectedValue.ToString());
StartActivity(Intent);
}
I am just wondering how I can implement the calling of the wcf service app and post the selected value to it. I am using Xamarin by the way
If you have set up your webservice, then just add a Service Reference in your project and all the exposed functions of your ws will be available through the proxy class which will be created when you added the reference.
I need to somehow attach my custom data to the HttpRequest being handled by my IIS custom modules - so that code that runs in earlier stages of IIS pipeline attaches an object and code that runs in later stages can retrieve the object and use it and no other functionality of IIS pipeline processing is altered by adding that object.
The data needs to persist within one HTTP request only - I don't need it to be stored between requests. I need it to be "reset" for each new request automatically - so that when a new request comes it doesn't contain objects my code attached to the previous request.
Looks like HttpContext.Items is the way to go, although MSDN description of its purpose is not very clear.
Is using HttpContext.Current.Items the way to solve my problem?
This should work - I have done this in a project before.
I have a class which has a static property like this -
public class AppManager
{
public static RequestObject RequestObject
{
get
{
if (HttpContext.Current.Items["RequestObject"] == null)
{
HttpContext.Current.Items["RequestObject"] = new RequestObject();
}
return (RequestObject)HttpContext.Current.Items["RequestObject"];
}
set { HttpContext.Current.Items["RequestObject"] = value; }
}
}
And then RequestObject contains all my custom data so then in my app I can do
AppManager.RequestObject.CustomProperty
So far I have not come across any issues in the way HttpContext.Items works.