Precautions for enumeration Enum in C #

Some time ago, the project compilation was normal because two different items in the same enumeration were accidentally written as the same value in the project. As follows:

Enum MyEnum
{
A = 1,
B = 1
}
With curiosity, I wrote code for verification:

Enum MyEnum
{
A,
B = 2,
C,
D = 2,
E,
F = 1,
G
}
I found that:

First:

Int a = (int) MyEnum. A; // a = 0
Int c = (int) MyEnum. C; // c = 3
Int e = (int) MyEnum. E; // e = 3
Int g = (int) MyEnum. G; // g = 2
(1) If no value is specified for the first item, the default value is 0.

(2) The value of an item is not necessarily unique in enumeration.

(2) If no value is specified, the value of the following item is "always" (for no reason, if a value already exists) equal to the value of the preceding item plus 1.

(3) Enumeration items are not necessarily sorted in ascending order.
 

Second point:

Bool result1 = (MyEnum. C = MyEnum. E); // true
Bool result2 = (MyEnum. B = MyEnum. G); // true
MyEnum myE = (MyEnum) 2; // MyEnum. B
(1) enumeration is a value type. During calculation, "value" is used for calculation.

(2) When the value is converted to enumeration, search from front to back.

 

I am sorry for writing too much. Please give me some comments and give me some advice.