How Can I Declare A Global Variables Model In BLAZOR?

Question

How Can I Declare A Global Variables Model In BLAZOR WASM? Let's say I have the following model and I want to be able to access every variable from the model anywhere in my entire project (pages, services, components, anywhere). Can you help me, please ?

public class UserInfoGlobalClass
{
    public string User_Name { get; set; } = "JOHN SMITH";
    public string User_Email { get; set; } = "JOHNSMITH@gmail.com";
    public string User_Role { get; set; } = "Administrator";
    public string USER_ID { get; set; } = "85f04683-0d37-4947-a09d-bbb464a92480";

}

Answer 1

You can inject your class as a singleton service:

builder.Services.AddSingleton<UserInfoGlobalClass>();

In a service include the class as a ctor paramater.

In a component or page: @inject UserInfoGlobalClass UserInfoGlobalClass

For this to be dynamic though. You will need to embellish your class with an event to notify pages and components to call StateHasChanged() when the contents are updated. I normally set the properties to private set and expose a method to change them that finally invokes the event to notify listeners.

public class UserInfoGlobalClass
{
    public string User_Name { get; private set; } = "JOHN SMITH";
    public string User_Email { get; set; } = "JOHNSMITH@gmail.com";
    public string User_Role { get; set; } = "Administrator";
    public string USER_ID { get; set; } = "85f04683-0d37-4947-a09d-bbb464a92480";
    
    public event EventHandler UserChangedEvent;

    public void SetUser(User user)
    {
        User_Name = user.Name;
        ... repeat for properties.
        UserChangedEvent?.Invoke();
    }
}

Use in another service.

builder.Services.AddScoped<SomeOtherService>();

public class SomeOtherService : IDisposable
{

    private readonly UserInfoGlobalClass userInfoGlobalClass;

    public SomeOtherService(UserInfoGlobalClass userInfoGlobalClass)
    {
        this.userInfoGlobalClass = userInfoGlobalClass;
        userInfoGlobalClass.UserChangedEvent += UserChanged;
    }

    public void UserChanged(object sender, EventArgs e)
    {
        // Process user details change.
    }

    public void SetNewUserMethod()
    {
         userInfoGlobalClass.SetUser(new User { ... });
    }

    
    public void Dispose() => userInfoGlobalClass.UserChangedEvent -= UserChanged;
}

In a page or component:

@implements IDisposable
@inject UserInfoGlobalClass UserInfoGlobalClass

...

@code {
    protected override void OnInitialized()
    {
        userInfoGlobalClass.UserChangedEvent += StateHasChanged;  
    }
    
    public void public void Dispose() => userInfoGlobalClass.UserChangedEvent -= StateHasChanged;
}