Asp.net obtains the ID of the inserted record.

Your SQL statement
String sqlstr = @ "insert into table (......) Values (......) Select scope_identity () as 'mynewid '";
Execute SQL
Sqldatareader mydr = use the executereader method to execute your SQL statement
Get ID
Mydr. getvalue (0). tostring ()

Note:
/* It is best to use ident_current ('tbname ')*/
Insert into table (field1, field2,...) values ("field1value", "field2value",...) Select ident_current ('recordid') as newidvalue

/* Use scope_identity () for the newly inserted Record ID that is used immediately */
Insert into table (field1, field2,...) values ("field1value", "field2value",...) Select scope_identity () as newidvalue

/* It is best to use @ identity */for the auto-increment ID obtained in a series of operations */
Insert into table (field1, field2,...) values ("field1value", "field2value",...) Select @ identity as newidvalue