CODEWITHSUNDEEP
c#singleton
Wesley
Wesley

Reputation: 5621

Instantiate Singleton with Variables

I'm using Jon Skeet's great guide on Singletons in C# found here:

Implementing the Singleton Pattern in C# (Sixth version - using .NET 4's Lazy type)

What I'm trying to do is create a reference class that contains configuration materials used by other classes throughout the program. (settings, themes, etc...)

That reference class has a dependence on a few variables that are provided by a ClientContext object (Scope, TenantID, etc)

For example, there is a settings object that is stored in a database, and needs the TenancyID to pull out the settings for the current scope.

How do I properly use the Singleton pattern, but delay instantiation until a variable is passed to it?

Addendum

In Jon's example, it instantiates itself based on a private static class that cannot be fed a variable.

private static readonly Lazy<Singleton> lazy =
    new Lazy<Singleton>(() => new Singleton());

public static Singleton Instance { get { return lazy.Value; } }

How do I feed a GUID representing an TenantID to a private static readonly variable?

Upvotes: 1

Views: 1791

Answers (1)

Adam Modlin
Adam Modlin

Reputation: 3024

You could make your singleton instance a Lazy<T>. This won't instantiate until you attempt to access it. For more examples, look here.

Edit: I just realized Jon Skeet even calls this out specifically in his guide.

Upvotes: 1

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