Is there any generic Parse() function that will convert a string to any type using parse?

System.Convert.ChangeType

As per your example, you could do:

int i = (int)Convert.ChangeType("123", typeof(int));
DateTime dt = (DateTime)Convert.ChangeType("2009/12/12", typeof(DateTime));

To satisfy your “generic return type” requirement, you could write your own extension method:

public static T ChangeType<T>(this object obj)
{
    return (T)Convert.ChangeType(obj, typeof(T));
}

This will allow you to do:

int i = "123".ChangeType<int>();