C ＃ method of obtaining a unique identification number (ID) based on the current time

In software development , We often have to distinguish between similar objects , For example, multiple variables generated in batch , Multiple annotations, etc . stay PLC-Recorder In the process of development ,ID The generation method of No. has also been optimized many times , Finally stabilized , Can be based on the current time , Generate non-repeating ID Number （ It is effective when the sudden demand is not very large ）, Share with you , Let friends also take fewer detours .

1、 Based on the current time

Because the software may restart , therefore , Will the history of ID Write it all down , It will be a great burden . therefore , Based on the current time ID Generate , Can avoid with history ID The conflict of .

Int64 ID = DateTime.Now.Ticks;

2、 Find out ID Repetition of No

Only use the above statement to generate ID Number is not enough , because , Batch generation , They are the same , therefore , Need to double check .

Will be effective ID Deposit in dictionary , You can check the duplicate quickly . The program generates itself ID after , Will be immediately stored in the dictionary . If it is generated by other programs , Pay attention to also store in the dictionary .

Of course , It may be easier to use a hip-hop watch , You can improve , I generate ID Your actions are not frequent , therefore , It doesn't matter .

3、 Handling when duplicate is found

If you find a repetition , Will ID++, Until you find something that doesn't repeat . Then the new ID Deposit in dictionary , And feedback out .

        /// <summary>
        ///  Use dictionary 
        /// </summary>
        /// <returns> new ID</returns>
        public static Int64 IDGetNew()
        {
            // confirm ID No repetition 
            Int64 ID = DateTime.Now.Ticks;
            while (LibID.ContainsKey(ID))
            {
                ID++;// Get a new ID
            }
            LibID.Add(ID, ID);
            
            return ID;
        }
        public static void IDAdd(long ID)
        {
            if (LibID.ContainsKey(ID)) return;
            LibID.Add(ID, ID);
        }
        private static Dictionary<long, long> LibID = new Dictionary<long, long>();

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