ช่วยหน่อยค่ะมีปัญหาเกี่ยวกับ AutoNumber ค่ะ (หัดใช้ Asp.Net ครั้งแรกเลยยังไม่ค่อยเข้าใจค่ะ)

Public Function KeyStore() As String
        Dim intNum, strSQL As String
        Dim sqlCon As New SqlConnection(con)
        'strSQL = "SELECT COUNT(*) FROM Store"
        strSQL = "SELECT replace(max(storeID),'ST','') AS storeID FROM Store"
        Dim cmd As New SqlCommand(strSQL, sqlCon)
        sqlCon.Open()
        intNum = cmd.ExecuteScalar()

        intNum += 1
        If intNum <= 9 Then
            intNum = "ST" & "0" & intNum
        ElseIf intNum > 9 Then
            intNum = "ST" & intNum

        End If
        sqlCon.Close()
        Return intNum

    End Function

Public Function KeyStore() As String
        Dim intNum, strSQL As String
        Dim sqlCon As New SqlConnection(con)
        strSQL = "SELECT MAX(storeID)  AS storeID FROM Store"
        Dim cmd As New SqlCommand(strSQL, sqlCon)
        sqlCon.Open()
        intNum = cmd.ExecuteScalar()
        sqlCon.Close()
        Return intNum

    End Function

        public string KeyStore() {
        string intNum, strSQL;
        SqlConnection sqlCon = new SqlConnection(con);
        strSQL = "SELECT MAX(storeID)  AS storeID FROM Store";
        SqlCommand cmd = new SqlCommand(strSQL, sqlCon);
        sqlCon.Open();
        intNum = (String)cmd.ExecuteScalar();
        sqlCon.Close();
        return intNum;

        }//End Function