Btukfyl

This is my first time attempting to read an Access database and write each row to the console. When I execute the application I get thrown an exception that says, "No value given for one or more required parameters" on the following statement:

OleDbDataReader reader = cmd.ExecuteReader();

I'm relatively new to c# programming and after hours of research, I can't figure out what I'm doing wrong. Here's my code:

private void maintenanceToolStripMenuItem_Click(object sender, EventArgs e)

    {

        //Use a variable to hold the SQL statement.

        string inputString = "SELECT Full_Name, First_Name, Last_Name, Company FROM CONTACTS";



        try

        {

            //Create an OleDbCommand object and pass in the SQL statement and OleDbConnection object

            OleDbCommand cmd = new OleDbCommand(inputString, conn);



            //Send the CommandText to the connection, and then build an OleDbDataReader.

            OleDbDataReader reader = cmd.ExecuteReader();



            while (reader.HasRows)

            {

                while (reader.Read())

                {

                    Console.WriteLine("t{0}t{1}", reader.GetString(1));

                    reader.NextResult();

                }

            }

            reader.Close();

        }

        catch (Exception ex)

        {

            error_message = ex.Message;

            MessageBox.Show(error_message);

        }

In response to the commenters, I'm posting a larger piece of code to eliminate any assumptions and give a better overall picture of what I'm trying to do:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Data.OleDb;

using System.IO;



namespace AzFloodSquad

{

    public partial class frm1DefaultScreen : Form

    {

        //Initialize the application

        String conn_string = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source = C:\Databases\AzFloodSquad\AzFloodSquad.accdb;Persist Security Info=False;";

        OleDbConnection conn = null;

        String error_message = "";

        String q = "";

        string varReportId = "";



    public frm1DefaultScreen()

    {

        InitializeComponent();

    }



    //Load the default form

    private void frm1DefaultScreen_Load(object sender, EventArgs e)

    {

        connectToolStripMenuItem.PerformClick();

        contactsToolStripMenuItem.PerformClick();

    }



    //Exit the application

    private void exitToolStripMenuItem_Click(object sender, EventArgs e)

    {

        Application.Exit();

    }



    //Start the database

    private void connectToolStripMenuItem_Click(object sender, EventArgs e)

    {

        try

        {

            conn = new OleDbConnection(conn_string);

            conn.Open();

            disconnectToolStripMenuItem.Enabled = true;

            connectToolStripMenuItem.Enabled = false;

        }

        catch (Exception ex) { MessageBox.Show(ex.Message); }

    }



    //Stop the database

    private void disconnectToolStripMenuItem_Click(object sender, EventArgs e)

    {

        try

        {

            conn.Close();

            disconnectToolStripMenuItem.Enabled = false;

            connectToolStripMenuItem.Enabled = true;

        }

        catch (Exception ex) { MessageBox.Show(ex.Message); }

    }



    //Clean up database whem form close button clicked

    private void frm1DefaultScreen_FormClosing(object sender, FormClosingEventArgs e)

    {

        disconnectToolStripMenuItem.PerformClick();

    }



    private void contactsToolStripMenuItem_Click(object sender, EventArgs e)

    {

        varReportId = "Contacts";

        q = "SELECT * " +

                "FROM CONTACTS WHERE CONTACTS.CONTACT_TYPE = 'CUSTOMER' " +

                    "OR CONTACTS.CONTACT_TYPE = 'HOMEOWNER' OR CONTACTS.CONTACT_TYPE = 'HOME OWNER' " +

                    "OR CONTACTS.CONTACT_TYPE = 'TENANT'" +

                        "ORDER BY FULL_NAME";



        this.Cursor = Cursors.WaitCursor;

        run_Query_Parm(q);

        this.Cursor = Cursors.Default;

    }



    //Pull data from the database using the parameter field

    private void run_Query_Parm(String q)

    {

        error_message = "";

        try

        {

            OleDbCommand cmd = new OleDbCommand(q, conn);

            OleDbDataAdapter a = new OleDbDataAdapter(cmd);



            DataTable dt = new DataTable();



            a.SelectCommand = cmd;

            a.Fill(dt);



            results.DataSource = dt;

            results.AutoResizeColumns();

        }

        catch (Exception ex)

        {

            error_message = ex.Message;

            MessageBox.Show(error_message);

        }

    }



    //Clear all data from the screen

    private void clearFormToolStripMenuItem_Click(object sender, EventArgs e)

    {

        varReportId = "";

        if (this.results.DataSource != null)

        {

            this.results.DataSource = null;

        }

        else

        {

            this.results.Rows.Clear();

        }

    }



    private void maintenanceToolStripMenuItem_Click(object sender, EventArgs e)

    {

        //Use a variable to hold the SQL statement.

        string inputString = "SELECT Full_Name, First_Name, Last_Name, Company FROM CONTACTS";



        try

        {

            //Create an OleDbCommand object and pass in the SQL statement and OleDbConnection object

            OleDbCommand cmd = new OleDbCommand(inputString, conn);



            //Send the CommandText to the connection, and then build an OleDbDataReader.

            OleDbDataReader reader = cmd.ExecuteReader();



            while (reader.HasRows)

            {

                while (reader.Read())

                {

                    Console.WriteLine("t{0}t{1}", reader.GetString(1));

                    reader.NextResult();

                }



            }

            reader.Close();

        }

        catch (Exception ex)

        {

            error_message = ex.Message;

            MessageBox.Show(error_message);

        }

    }

Any help provided would be greatly appreciated. Thanks in advance.

I found the problem. Apparently, I had improper syntax on my SELECT statement. When I replaced my SELECT, (shown in the first code example I posted), with the following, it worked fine:

string inputString = "SELECT Contacts.[Account_Number], " +

            "Contacts.[Full_Name], Contacts.[ID], Contacts.[Street], " +

            "Contacts.[City], Contacts.[State], Contacts.[Zip] FROM Contacts";