When I change the value of a variable which is a copy of another, it changes the original variable also

Question

public class TestClass
{
    public int TestNumber;
    public string TestName;

    public TestClass(string name, int number)
    {
        TestName   = name;
              


        

Answer 1

C# is a pass by reference language, when dealing with objects. So when you say Var2 = Var, you're saying that Var2 now holds the address of whatever address Var1 was holding, effectively making them point to the same object.

One work around is to turn it into a pass by value, like so:

public void Start()
{
    Var1 = new TestClass("Me", 1);
    Var2 = new TestClass();           // You would need a default constructor, and to use it to prevent the null exception error

    Var2.TestNumber = Var1.TestNumber;
    Var2.TestName   = "aaa";

}

Or, if you will be using more values and this is an overly simplified example, you can use another approach:

public void Start()
{
    Var1 = new TestClass("Me", 1);
    Var2 = Var1.GetValues();
}

And in your test class:

public testClass GetValues() => return new testClass(TestNumber, TestName);