【转】C#中的implicit 和 explicit

The implicit and explicit keywords in C# are used when declaring conversion operators. Let's say that you have the following class:

public class Role
{
    public string Name { get; set; }
}

If you want to create a new Role and assign a Name to it, you will typically do it like this:

Role role = new Role();
role.Name = "RoleName";

Since it has only one property, it would perhaps be convenient if we could instead do it like this:

Role role = "RoleName";

This means that we want to implicitly convert a string to a Role (since there is no specific cast involved in the code). To achieve this, we add an implicit conversion operator:

public static implicit operator Role(string roleName)
{
    return new Role() { Name = roleName };
}

Another option is to implement an explicit conversion operator:

public static explicit operator Role(string roleName)
{
    return new Role() { Name = roleName };
}

In this case, we cannot implicitly convert a string to a Role, but we need to cast it in our code:

Role r = (Role)"RoleName";