C#•12mo ago

Blazor Services

I dont know too much blazor, but I have a .cs file in a /Settings folder, in which I would like to access a service which is storing state. (The service called State is stored in /Appearance). In razor components, i can just use @inject State state, and then access and modify it using state.<prop> How can i do the same inside of a standard c# file?

4 Replies

deathlybower959•12mo ago

(ping if replying)

x0rld 👻 🎃•12mo ago

you want to change a property in your State right ? 🤔 @DeathlyBower959 just add in any ctor your State to inject it and modify it

deathlybower959•12mo ago

i think so yea this is my ThemeState.cs

public class ThemeState
{
    public CssBuilder ThemeCSS { get; set; }
    public event Action OnChange;

    public ThemeState() { ThemeCSS = CssBuilder.FromFile(ThemePath, ":root"); }

    public static readonly string WWWRootPath = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)!, "wwwroot");

    public static readonly string ThemePath = Path.Combine(WWWRootPath, "css", "theme.css");

    public void ApplyTheme(CssBuilder css)
    {
        ThemeCSS = css;
        OnChange?.Invoke();
    }

    public void UpdateTheme(string property, string value)
    {
        ThemeCSS.SetProperty(property, value);
        OnChange?.Invoke();
    }
}

public class ThemeState
{
    public CssBuilder ThemeCSS { get; set; }
    public event Action OnChange;

    public ThemeState() { ThemeCSS = CssBuilder.FromFile(ThemePath, ":root"); }

    public static readonly string WWWRootPath = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)!, "wwwroot");

    public static readonly string ThemePath = Path.Combine(WWWRootPath, "css", "theme.css");

    public void ApplyTheme(CssBuilder css)
    {
        ThemeCSS = css;
        OnChange?.Invoke();
    }

    public void UpdateTheme(string property, string value)
    {
        ThemeCSS.SetProperty(property, value);
        OnChange?.Invoke();
    }
}

its a simple state and i have added it to my services in MainWindow.xaml.cs

services.AddSingleton<ThemeState>();

        Resources.Add("services", services.BuildServiceProvider());

services.AddSingleton<ThemeState>();

        Resources.Add("services", services.BuildServiceProvider());

Im trying to access it in a .cs file, but im having some trouble

private readonly ThemeState _state;

public MyClass(ThemeState state = null)
{
    _state = state;
}

private readonly ThemeState _state;

public MyClass(ThemeState state = null)
{
    _state = state;
}

i tried this but its always null (i have to set a default value because i initialize this class to get default values)

Joschi•12mo ago

If you initialize a class yourself like with new MyClass() you would need to provide the dependency yourself. Automated DI only works if the framework creates something for your, like a razor component. So you would need access to the underlying service provider and use something like public static T? GetService<T> (this IServiceProvider provider);

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