Why can't I use instance methods in a dictionary field initializer in C#?

I'm trying to initialize a dictionary that stores functions using a collection initializer, but I'm running into a compiler error. The error says:

CS1950 The best overloaded Add method 'Dictionary<Func, string>.Add(Func, string)' for the collection initializer has some invalid arguments FuncDictonaryTest

The code works if I move the initialization to the constructor. Here’s the code that demonstrates the issue:

CSHARPCopied
test
namespace FuncDictonaryTest
{
    internal class Program
    {
        private Dictionary<Func<bool>,
                           string> FunctionDictonary = new()
                           {
                                { TestA, "Hello" },
                                { TestB, "Byebye" }, // Not working
                            };

        private Dictionary<Func<bool>,
                           string> FunctionDictonaryTwo;

        Program()
        {
            FunctionDictonaryTwo = new() // Working
            {   
                { TestA, "Hello" },
                { TestB, "Byebye" }
            };
        }

        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }

        private bool TestA()
        {
            return true;
        }

        private bool TestB()
        {
            return false;
        }
    }
}

This happens because instance field initializers run before the constructor is executed, meaning the instance ("this") isn't available yet. As a result, referencing non‑static methods like TestA and TestB in the field initializer is not allowed. Initializing the dictionary inside the constructor or making these methods static resolves the error.