How can I create a global variable in an ASP.NET Core Web API application? In ASP.NET MVC, I could do it like:
Application["<variableName>"] = <value>
I tried the same in my web API application, but was unable to find an equivalent for this. I saw some solutions which suggested me to store the data appsettings.json, but since the data I want to store in the global variable is not static, I cannot use that setup. I need to set different data during runtime. How can I do that? Please help me.
somewhere in project
public static class Config{
public static Dictionary<string,string> Application = new Dictionary<string,string>();
}
elsewhere
Config.Application["froop"] = "noodle";
of course you will have to deal with race conditions, etc
We could use Singleton_pattern , creating an Application static object in .net core.
we can also try to use Depend Injection, register a singleton object as below in your code.
Writing a property ConcurrentDictionary in ApplicationInstance class.
public class ApplicationInstance {
public ConcurrentDictionary<string,object> Application { get; } = new ConcurrentDictionary<string, object>();
}
public void ConfigureServices(IServiceCollection services){
services.AddSingleton<ApplicationInstance>();
}
Then we might use this object
public class HomeController : ControllerBase
{
private readonly ApplicationInstance _application;
public HomeController(ApplicationInstance application)
{
this._application = application;
}
//use _application["test"] instance in your code
}
I would use ConcurrentDictionary to help us avoid racing-condition which will be happened on multiple-thread accessing the same object concurrently.
First of all thank you all for finding some time to help me. I took @pm100's solution and made a slight modification to suit my purpose. I could not use it directly as I am using SonarLint, and it had some issues, so I used a KeyValuePair instead of Dictionary like this:
public static class GlobalData
{
public static KeyValuePair<string,object> Application { get; set; }
}
and I used it in my code like:
string value = GlobalData.Application.Value
and luckily it works without any issue.
public static KeyValuePair<string,object> Application suited my purpose " and marking @pm100 answer gives you a few points :)
KeyValuePair will allow you to store only one variable at a time. Is this what you were looking for? If you want to store list of variables, consider using List<KeyValuePair<string, object>>, or as @pm100 suggested - Dictionary, which has easier to use API than List<KeyValuePair>. (I'm not sure why SonarLint would allow you to use KeyValuePair, but not Dictionary)
IOptions<T>doesn't require anything inappsettings.json. Instead you can populate constants withservices.Configure<Type>(o => { o.Prop = "value"; });. Which would make it easier to change to json config later.