table column accepting "0" as a member Id
- by user682417
I have two tables one is members table  with columns member id , member first name, member last name. I have another table guest passes with columns guest pass id and  member id  and issue date  .
I have a list view that will displays guest passes details (I.e) like member name and  issue date and I have two text boxes those are for entering member name and issue date .
member name text box is auto complete text box that working fine....
but the problem is when I am entering the name that is not in member table at this time it will accept and displays a blank field in list view in  member name  column and member id is stored as "0" in guest pass table ......
I don't want to display the member name empty  blank and  I don t want to store "0" in guest pass table 
and this is the insert statement 
          sql2 = @"INSERT INTO guestpasses(member_Id,guestPass_IssueDate)";
          sql2 += " VALUES(";
          sql2 += "'" + tbCGuestPassesMemberId.Text + "'";
          sql2 += ",'" + tbIssueDate.Text + "'";
guestpassmemberId = memberid
is there any validation that need to be done 
can any one suggestions on this pls...
and this is the auto complete text box statement 
           sql = @"SELECT member_Id FROM members WHERE  concat(member_Firstname,'',member_Lastname) ='" + tbMemberName.Text+"'";
         if (dt != null)
         {
            if (dt.Rows.Count > 0)
            {
                tbCGuestPassesMemberId.Text  = Convert.ToInt32(dt.Rows[0]  ["member_Id"]).ToString();
            }
         }
can any one help me on this ...
  is there any type of validation with sql query
pls help me .....