ExecuteNonQuery Overflow Error ?

Question

I've been trying to figure what is wrong with the code.

What I'm trying to do is that there are two Radiobuttons for gender, Male & Female...

I want that when Male radiobutton is clicked, the text MALE is saved into the database in the gender field which if of type text, but instead I'm getting an overflow error...

Before adding the radiobuttons and the [GENDER] field, everything was working fine...

So any help with it?

    using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;

namespace OfflineRF
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        string gender;

        private void button1_Click(object sender, EventArgs e)
        {
            string ORF1 = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source = C:\\OfflineRF.mdb";
            OleDbConnection conn = new OleDbConnection(ORF1);
            conn.Open();
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandText = "INSERT INTO OFFRF([Fname], [Lname], [NIC], [Gender], [HomeTel], [Cellphone], [Passengers], [From], [To])VALUES('" + textBox1.Text + "','" + textBox2.Text + "','" + textBox3.Text + textBox7.Text + textBox8.Text +"','"+gender+"','" + textBox4.Text + "','" + textBox5.Text + "','" + textBox6.Text + "','" + comboBox1.Text + "','" + comboBox2.Text + "')";
            cmd.ExecuteNonQuery();
            conn.Close();
            System.Windows.Forms.MessageBox.Show("Form Saved Successfully !", "Caption", MessageBoxButtons.OKCancel, MessageBoxIcon.Information);

            textBox1.Text = "";
            textBox2.Text = "";
            textBox3.Text = "";
            textBox4.Text = "";
            textBox5.Text = "";
            textBox6.Text = "";
            textBox7.Text = "";
            textBox8.Text = "";
            comboBox1.SelectedIndex = -1;
            comboBox2.SelectedIndex = -1;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox1.Text == "Karachi")
            {
                comboBox2.Items.Clear();
                comboBox2.Items.Add("Sukkur");
                comboBox2.Items.Add("Hyderabad");
            }
            else if (comboBox1.Text == "Sukkur")
            {
                comboBox2.Items.Clear();
                comboBox2.Items.Add("Karachi");
                comboBox2.Items.Add("Hyderabad");
            }
            else
            {
                comboBox2.Items.Clear();
                comboBox2.Items.Add("Karachi");
                comboBox2.Items.Add("Sukkur");
            }
        }

        private void Male_CheckedChanged(object sender, EventArgs e)
        {
            if (Male.Checked)
                gender = "Male";
            else
                gender = "Female";
        }

    }
}

Answer 1

Aside from the possibility of SQL-Injection by adding your values in a concatenated string, you could also be failing if someone were to put in a name value like "O'Conner" where the quote in the name would terminate the string and throw the rest off.

Look into OleDbParameter object and setting them. Without exact syntax you would do something like

string ORF1 = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source = C:\\OfflineRF.mdb";
OleDbConnection conn = new OleDbConnection(ORF1);
conn.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = conn;
cmd.CommandText = "INSERT INTO OFFRF( Fname, Lname, NIC, Gender, HomeTel, "
           + "Cellphone, Passengers, [From], [To] ) VALUES "
           + "(  ?, ?, ?, ?, ?, ?, ?, ?, ? )";
// Add parameters in same ordinal position as the "?" place-holders
// the first parameter is more of generic description of WHAT it is for and 
// does NOT have to exactly match the column name, the second parameter is
// the actual value that should be put into the database.  This same context
// is used for performing other SQL actions (select, delete, update, etc)
// to help prevent SQL injection.
cmd.Parameters.Add( "valForFName", textBox1.Text );
cmd.Parameters.Add( "valForLName", textBox2.Text );
cmd.Parameters.Add( "valForNIC", textBox3.Text + textBox7.Text + textBox8.Text );
// Not sure of syntax here, but get proper text from your radio choice of gender into string
gender = YourForm.RadioForGender.SelectedItem.Text;  
cmd.Parameters.Add( "valForGender", gender );
cmd.Parameters.Add( "valHomePhone", textBox4.Text );
cmd.Parameters.Add( "valCell", textBox5.Text );
cmd.Parameters.Add( "howmany", textBox6.Text );
cmd.Parameters.Add( "forFromValue", comboBox1.Text );
cmd.Parameters.Add( "forToValue",  comboBox2.Text );
cmd.ExecuteNonQuery();
conn.Close();

Answer 2

You have an infinite loop. When the combo box changes the selectedindex event is raised, then you change the combo box and the event fires again.

Edited...

At the end of the button event handler you are changing the combo box Indexes again causing an endless loop of event firing and the ensuing stackoverflow