How to generate Custom ID - vb.net

Question

I want to create a custom value for the ID. For example, it will start with "CR00001" and after that it will increment the numerical portion (e.g. CR00002) when I save the data for the second time.
Here is the code I am using:
Dim cr_id As String
cr_id = "CR00001"
Dim iReturn As Boolean
Using SQLConnection As New MySqlConnection(strConnectionString)
Using sqlCommand As New MySqlCommand()
sqlCommand.Connection = SQLConnection
With sqlCommand
.CommandText = "INSERT INTO cr_record(idcr_record,Emplid,isu,Nama,date1,DeptDesc,email,change1,reasonchange,problem,priority,reasondescription,systemrequest,attachment) VALUES (#cr_id,#Emplid,#isu,#Nama,#date1,#DeptDesc,#email,#change1,#reasonchange,#problem,#priority,#reasondescription,#systemrequest,#attachment)"
.CommandType = Data.CommandType.Text
.CommandTimeout = 5000
.Parameters.AddWithValue("#cr_id", cr_id)

Answer 1

When you want to generate a new ID, write one function for generating the ID, and copy this code there. Keep the return type as String to return newId.
Dim newId As String
Dim stringId As String
Dim intId As Integer
Dim conn As New System.Data.SqlClient.SqlConnection("Your database query string")
Dim adpt As New System.Data.SqlClient.SqlDataAdapter("Select id from tableName Where date = (SELECT max(date) from tableName)", conn) 'Where tableName is you table
Dim ds As New DataSet
adpt.Fill(ds)
If ds.Tables(0).Rows.Count = 0 Then 'This will check whether any records are there or not
newId = "CR00001" ' If records are not there then this id will be returned
Else
stringId = ds.Tables(0).Rows(0).Item(0).ToString 'This will store your id in string format
intId = stringId.Substring(2) ' This will store only integer values from that id
intId += 1 ' Increment id by 1
newId = String.Concat("CR", intId) ' Creating new Id incremented by 1
End If
Return newId