Database

private void btnLogin_Click(object sender, System.EventArgs e) <br />
          { <br />
            //The connection string is used to describe the type of database, the security information and the location to the database. <br />
            string ConString = "Data Source=porky;Initial Catalog=IS3_sysdev;Integrated Security=True"; <br />
            //Create a new connection object and assign the ConString Connection String above <br />
            OleDbConnection DBCon = new OleDbConnection(ConString); <br />
            // g_login is a global variable defined in a Module that captures the login name and passes it from form to form. To create this, just create a Module, say Module1.vb and in it put "Public g_login as String" {g meaning global and login to represent the global login} <br />
            GlobalVariables.g_login = this.textBox1.Text; <br />
            <br />
            string strPassword = this.textBox2.Text;<br />
<br />
            if (GlobalVariables.g_login == "" || strPassword == "")<br />
            { <br />
                MessageBox.Show("You are missing information. Please make sure that both the username and password fields are filled out.", "Missing Info"); <br />
                this.textBox1.Focus(); <br />
                return; <br />
            } <br />
            // The database has two fields in the Users table. A UserID field, which is the primary key and declared as a text. The other field is Password, which is a text as well. <br />
            string strsql = "SELECT [UserID], [Password] FROM Users WHERE [UserID]='" + GlobalVariables.g_login + "' "; <br />
            <br />
            OleDbCommand cm = new OleDbCommand(strsql, DBCon); <br />
            OleDbDataReader dr; <br />
            bool valid = false; <br />
            bool HasRows = false; <br />
            try { <br />
                DBCon.Open();<br />
                dr = cm.ExecuteReader(); <br />
                if (dr.HasRows) { <br />
                    while (dr.Read()) { <br />
                        if (strPassword == dr.GetString(1)) { <br />
                            valid = true; <br />
                        } <br />
                    } <br />
                    HasRows = true; <br />
                } <br />
                dr.Close(); <br />
            } <br />
            catch (OleDbException exO) { <br />
                MessageBox.Show(exO.Message); <br />
            } <br />
            catch (Exception ex) { <br />
                MessageBox.Show(ex.Message); <br />
            } <br />
         //   finally { <br />
           //     if (DBCon.State == ConnectionState.Open) { <br />
             //       DBCon.Close(); <br />
               // } <br />
           /*     cm = null; <br />
                dr = null; <br />
                DBCon.Dispose(); <br />
                GC.Collect(); */<br />
           // } <br />
            iCount = iCount + 1; <br />
            if (valid == true) {<br />
                Form n = new Form4();<br />
                n.Show();<br />
                this.Hide();<br />
            } <br />
            else if (iCount == 3) { <br />
                MessageBox.Show("Contact Developers!", "Invalid Info"); <br />
                this.Close(); <br />
            } <br />
            else if (HasRows == false) { <br />
                MessageBox.Show("Invalid user name, try again!", "Invalid Info"); <br />
                this.textBox1.Focus(); <br />
                this.textBox1.Text = ""; <br />
                this.textBox2.Text = ""; <br />
            } <br />
            else { <br />
                MessageBox.Show("Invalid password, try again!", "Invalid Info"); <br />
                this.textBox2.Focus(); <br />
                this.textBox2.Text = ""; <br />
            } <br />
            <br />
       }