Implement AutoIncrement ID in Table without setting Identity Column in SQL Server

Hi! Ihave table person:

ID              FirstName                  Name

1                Asrori                       Yatim

2                Safarov                     Sarabek

3                Malaev                      Nurullo

But I want create auto_increment in the procedure sql or in asp.net for automaticaly insert id.

Before insert id first of all check sort id and insert id. If id not by sort such:

Id

1

3

4

6

Then sort it’s id such:

Id

1

2

3

4

5

6

Then insert 7,8 and ect.