I am upgrading a web site from MVC3 to MVC5. I simply used NuGet to install Microsoft.AspNet.Mvc version 5.2.3 and everything seemed to be working fine. But upon closer examination I noticed that this code was no longer running:
public abstract class BaseController : System.Web.Mvc.Controller
{
protected override void Execute(RequestContext requestContext)
{
LogRequest();
UpdateUserSession();
base.Execute(requestContext);
}
}
I found this lifecycle documentation (linked from here) which seems to confirm that Execute is no longer called by MVC.
However, this documentation is unclear, saying
This method is an implementation of Execute. You typically do not have to override this method. Override Initialize or ExecuteCore instead.
I would expect it to say "This method is no longer called by the MVC framework as of version 5 (or maybe 4)." Perhaps even mark it [Obsolete], although there may have been good reasons not to do that.
Furthermore, my testing shows that ExecuteCore does not get called either! It looks like OnActionExecuting is the best place to move the code that used to live in Execute, is that correct?
Maybe it helps to anybody:
Old version:
errorManagerController.Execute(requestContext);
New version:
Response.RedirectToRoute(routeData.Values);
Related
I've been tasked with maintaining a Xamarin native project using MvvmCross 5.6.2. Not knowing exactly how to approach this, I've decided to update to one major version at a time (6 first, then 7 and 8). I'm not sure why I specifically have chosen 6.4.2, but it was maybe because this was the latest version of the majority of the plugins I was using on Nuget.
So far, the update has been a success and I have been able to fix all build errors. However, when running the application, I've been getting a null reference exception which I can't fully trace.
Based on the limited application output, I've been able to determine that the problem lies somewhere in my Android's setup.cs class (I think). I've been following Nick's .NET Travels advice on MvvmCross debugging. From viewing the MvvmCross 6.4.2. source and pasting in the following code in my own overrides:
public virtual void LoadPlugins(IMvxPluginManager pluginManager)
{
Type pluginAttribute = typeof(MvxPluginAttribute);
IEnumerable<Assembly> pluginAssemblies = GetPluginAssemblies();
foreach (Assembly item in pluginAssemblies)
{
IEnumerable<Type> enumerable = item.ExceptionSafeGetTypes();
foreach (Type item2 in enumerable)
{
if (TypeContainsPluginAttribute(item2))
{
pluginManager.EnsurePluginLoaded(item2);
}
}
}
bool TypeContainsPluginAttribute(Type type)
{
object[] customAttributes = type.GetCustomAttributes(pluginAttribute, inherit: false);
return ((customAttributes != null && customAttributes.Length != 0) ? 1 : 0) > (false ? 1 : 0);
}
}
public virtual IEnumerable<Assembly> GetPluginAssemblies()
{
string mvvmCrossAssemblyName = typeof(MvxPluginAttribute).Assembly.GetName().Name;
Assembly[] assemblies = AppDomain.CurrentDomain.GetAssemblies();
var test = from asmb in assemblies.AsParallel()
where AssemblyReferencesMvvmCross(asmb, mvvmCrossAssemblyName)
select asmb;
return test;
}
I'm able to see that GetPluginAssemblies doesn't return any enumerable, and the LoadPlugins method then produces the NullReferenceException. But I can't see what this NullReference actually is.
I followed the upgrading from 5 to 6 guide https://www.mvvmcross.com/documentation/upgrading/upgrade-to-mvvmcross-60.
I looked at the MvvmCross 6 and 6.4.0 release pages:
https://www.mvvmcross.com/mvvmcross-6.0.0-release/
https://www.mvvmcross.com/mvvmcross-6.4.0-release/
And I followed Benjamin Mayrargue's guide: https://medium.com/#bigoudi/upgrading-from-mvvmcross-5-to-mvvmcross-6-7ded83ecb69d
But I have been unable to load my plugins (previously they were bootstraps, but most of the guides say these can be discarded now and that loading plugins is easier).
I also attempted the answer suggested in this question How to use an mvvmcross plugin such as the file plugin.
But to no avail.
So I am asking if anyone knows a good guide or how to use plugins in MvvmCross 6.4.2.
Thank you.
Plugins are just a way to register things in the IoC Container. This is done by MvvmCross during startup using the LoadPlugins method in your Setup file.
Most of the time it should just work. However, there are some caveats.
If the Linker has gone ahead and linked away some of the plugins code, you will have a bad time. What you can do about that is to hint the mono linker to not strip the code away.
Add a LinkerPleaseInclude class and add a Include method in it that looks something like:
new MvvmCross.Plugin.Color.Platforms.Ios.Plugin().Load();
You can do that for every plugin you may want to use.
If LoadPlugins doesn't find the entry Assembly, sometimes it also does not register the plugins. You can override LoadPlugins in your Setup class and just call EnsurePluginLoaded:
public override void LoadPlugins(IMvxPluginManager pluginManager)
{
base.LoadPlugins(pluginManager);
pluginManager.EnsurePluginLoaded<MvvmCross.Plugin.Color.Platforms.Ios.Plugin>();
}
I want to thank Cheesebaron for his plugin support. I think I've fixed my issue and as it turned out, I don't think there is a plugin issue after all (yet).
Thanks to Toolmakersteve also. His suggestion for using a try catch in the OnCreate of my overridden MvxSplashScreenAppCompatActivity surfaced an issue with setting a theme for this activity. In actuality, this class was initially a MvxSplashScreenActivity.
Reverting this line, I then started getting NullReferenceExceptions on specific lines, all relating to IoC and lazy construction of singletons. The class Mvx seemed to be throwing up this error. On a sort of hunch from previous experience with my updating, I removed the MvvmCross.Platform using statement and checked what suggestions Mvx had available to it. It suggested MvvmCross and MvvmCross.Platform, so I tried the former instead. Sure enough, this moved my execution further, throwing up more Null Reference Exceptions. I also encountered one instance of failing to resolve IMvxResourceLoader from MvvmCross.Platform.Platform. Switching that to MvvmCross.Base did the trick.
This was only a chance fix through a bit of guess work. #CheeseBaron, should I add this as a note to this bit of documentation https://www.mvvmcross.com/documentation/upgrading/upgrade-to-mvvmcross-60? As mentioned, I'm as far as 6.4.2 now, so I'm not certain this is the right place for it.
I've got a few bugs with embedded resources to fix now, but if I encounter any more that are relevant to my question, I'll list them here.
I'm trying to scaffold a new razor view using Visual Studio. I select a template, my model and my DbContext, then I get the error message shown below.
Things to note. My models, my DbContext and my website are all in different projects. From the message below I am using AddDbContext and I have a constructor that accepts a DbContextOptions<TContext> parameter.
I read a comment on a blog post that the issue is because my context is in another project. The comment referenced something about the need to inject the Configuration into the DbContext to get the connection string and manually add it in the OnConfiguring override.
I can't find any examples if this is correct or how to set it up. Any help would be appreciated.
EDIT:
Testing out the theory from the blog comment I mentioned above, I added this section into my DbContext. ConnectionString is a hardcoded string constant with my connection information. This does work and allow me to scaffold, so the question still remains. How can I inject this connection string into my DbContext to allow the scaffolding to work?
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseSqlServer(ConnectionString);
}
else
{
base.OnConfiguring(optionsBuilder);
}
}
EDIT: So after making this change, I checked in the code and had another developer pick it up. It appears this section above just needs to be there to allow scaffolding to work. He never changed the connection string to point to his environment. He no longer got the error above it just worked.
I am not sure about what is the actual problem but it seems like we were having problems creating DbContext at design time. I manually added the code below and it's working now. It's just a temporary solution tho.
public AppDbContext CreateDbContext(string[] args)
{
var optionsBuilder = new DbContextOptionsBuilder<AppDbContext>();
optionsBuilder.UseSqlServer("Data Source=.;Initial Catalog=JwtTemplate;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False");
return new AppDbContext(optionsBuilder.Options);
}
Reference: https://stackoverflow.com/a/70559350
I started using MVVMCross several weeks ago and so far I love it, but I've noticed that whenever I'm working on the UI and making changes in the XAML and pressing save which activates the Hot Reload in Visual Studio 2019, I'm getting Null Reference Exceptions.
This is down to the fact that the MVVMCross' Prepare method is not getting called. According to their doc's this method is used to pass a parameter to the VM which can then be used throughout the VM.
public override void Prepare(MyClass param)
{
MyClass = param;
}
public override Task Initialize()
{
MyClass.DoSomething();
return base.Initialize();
}
So this is the basic usage (I think). However when I Hot Reload the XAML changes Prepare isn't called but Initialize is, which causes the Exception.
Is this a bug ?
Prepare in normal cases will only be called when calling NavigationService.Navigate.
What Hot Reload actually does is unclear. This use case is currently not officially supported by MvvmCross.
We are evaluating FiddlerCore for a use-case. Basically, for now we just want to catch all of the endpoints/urls being requested on a system. This works fine in Fiddler, no issues. But we only want to catch them while a certain vendor software is open. So we want to write a plugin to that software that will run when it launches, and then exit when it exits. Hence, using FiddlerCore (hopefully).
As proof-of-concept, I just made a simple app, one form with a textbox, that it should just append each url into the textbox. Simple as simple can be. However, it's not doing anything. I run the app, then refresh a page in my browser, and ... nothing.
Here is the entire (non-generated) code of my program...
using Fiddler;
using System;
using System.Windows.Forms;
namespace ScratchCSharp {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
FiddlerApplication.AfterSessionComplete += FiddlerApplication_AfterSessionComplete;
FiddlerApplication.Startup(8888, FiddlerCoreStartupFlags.Default);
}
private void FiddlerApplication_AfterSessionComplete(Session s) {
textBox1.Invoke((Action)delegate () {
AddText(s.fullUrl);
});
}
public void AddText(string text) {
textBox1.Text += $"{text}\n";
}
}
}
After a little more poking around, I see that FiddlerApplication.IsSystemProxy is returning false. Seems to have to do with that the Startup flag to set as system proxy is no longer honored, and it tells you now to use the Telerik.NetworkConnections.NetworkConnectionManager to set it as the system proxy. But I can't find anywhere that actually says how to do that. The closest thing I could find is this thread which seems to be their official answer to this question. However, it only goes into a lot of talk about WHY they deprecated the flag, and what their thinking was in how they designed its replacement, but not actually into HOW TO USE the replacement. The Demo app also does NOT use these libraries (probably why it doesn't catch anything either).
The biggest problem though, is that the NetworkConnectionsManager class has no public constructor, so you can't create an instance. It is not inheritable, so you can't make a subclass instance. All of the methods on it are instance methods, not static/shared. And there seems to be no method in the libraries which will create an instance of NetworkConnectitonsManager for you.
So while the class is clearly designed to be used as an instance (hence the methods not being static/shared, there doesn't actually seem to be any way to create an instance.
Any help on how to set this thing up to catch all the outgoing URLs on the system?
You can use the following code for starting Fiddler Core and registering it as a system proxy:
FiddlerCoreStartupSettings startupSettings =
new FiddlerCoreStartupSettingsBuilder()
.ListenOnPort(fiddlerCoreListenPort)
.RegisterAsSystemProxy()
.ChainToUpstreamGateway()
.DecryptSSL()
.OptimizeThreadPool()
.Build();
FiddlerApplication.Startup(startupSettings);
Some of the methods are obsolete for now, but I would recommend to stick with them until the NetworkConnectionManager API is improved and finalized.
Also, there is a sample application (that FiddlerCore installer installs on the Desktop), which is useful for a starting point with the development.
I have installed Glimpse (Glimpse MVC4) and MiniProfiler (with EF support).
I also installed the MiniProfiler plugin for Glimpse.
I have that all wired up and working. I want to allow the configuration of Glimpse to determine if MiniProfiler should start profiling. That is, if Glimpse is enabled (through Glimpse.axd not via a config setting) I want to call MiniProfiler.Start() in the Application_BeginRequest() method. So, something like this:
protected void Application_BeginRequest()
{
if (Glimpse.IsRunning)
{
MiniProfiler.Start();
}
}
Is there a way to determine if Glimpse is enabled?
Technically there is a way, but I'd call it hacky at best. I'll let you decide if it is a good fit for your purposes.
var policyString = HttpContext.Current.Items["__GlimpseRequestRuntimePermissions"].ToString();
RuntimePolicy glimpsePolicy;
RuntimePolicy.TryParse(policyString, out glimpsePolicy);
if (!glimpsePolicy.HasFlag(RuntimePolicy.Off))
{
MiniProfiler.Start();
}
The reason I call it a hack is because while Glimpse may be On at the beginning of request, it may be later turned Off.
An example of this behavior is when Glimpse automatically shuts off once ASP.NET begins to report an unsupported media type, like an image. ASP.NET does not have the ability to know the media type until after the HTTP Handler has run. In this case, Glimpse will say that it is on at the beginning of the request, but then will be off at the end of it.