private static void ProblemWhenNotOverrideHashcode()
{
// Problem when not override GetHashcode
var pe1 = new PersonE {
FirstName = "Jeffrey", LastName = "Ye"
};
var pe2 = new PersonE {
FirstName = "Jeffrey", LastName = "Ye"
};
Dictionary <PersonE, string> PersonPositionDic = new();
PersonPositionDic.Add(pe1, "Software Engineer");
PersonPositionDic.Add(pe2, "Mechanical Engineer"); // NOT report duplicate key error!
string pos = PersonPositionDic[new PersonE {
FirstName = "Jeffrey", LastName = "Ye"
}]; // Will throw KeyNotFoundException
Console.WriteLine(pos);
Console.WriteLine();
}
private static void OverrideEqualOperator()
{
// How == will act when not override
var pc1 = new PersonC {
FirstName = "Jeffrey", LastName = "Ye"
};
var pc2 = new PersonC {
FirstName = "Jeffrey", LastName = "Ye"
};
Console.WriteLine($"pc1.Equals(pc2): {pc1.Equals(pc2)}");
Console.WriteLine($"pc1 == pc2: {pc1 == pc2}");
Console.WriteLine();
// Wrong implementation lead to infinite loop
var pd1 = new PersonD {
FirstName = "Jeffrey", LastName = "Ye"
};
var pd2 = new PersonD {
FirstName = "Jeffrey", LastName = "Ye"
};
Console.WriteLine($"pc1 == pc2: {pd1 == pd2}"); // this will be a infinite loop
Console.WriteLine();
// Correct implementation
var pe1 = new PersonE {
FirstName = "Jeffrey", LastName = "Ye"
};
var pe2 = new PersonE {
FirstName = "Jeffrey", LastName = "Ye"
};
Console.WriteLine($"pe1.Equals(pe2): {pe1.Equals(pe2)}");
Console.WriteLine($"pc1 == pc2: {pe1 == pe2}");
Console.WriteLine();
}