Data Checker : TextBox : GUI Windows Form C# Source Code

    

/*
Professional Windows GUI Programming Using C#
by Jay Glynn, Csaba Torok, Richard Conway, Wahid Choudhury, 
   Zach Greenvoss, Shripad Kulkarni, Neil Whitlow

Publisher: Peer Information
ISBN: 1861007663
*/
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
using System.Threading;


namespace DataChecker
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class DataChecker : System.Windows.Forms.Form
    {
        private System.Windows.Forms.TextBox txtCoffeePrice;
        private System.Windows.Forms.TextBox txtTeaPrice;
        private System.Windows.Forms.TextBox txtGoldPrice;
        private System.Windows.Forms.Label lblCoffeePrice;
        private System.Windows.Forms.Label lblTeaPrice;
        private System.Windows.Forms.Label lblGoldPrice;

        private int lastCoffeePrice = 0;
        private int lastTeaPrice = 0;
        private int lastGoldPrice = 0;
        private int allUpdates = 0;

        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;
        private System.Threading.Timer t1 = null;
        private System.Threading.Timer t2 = null;
        private System.Threading.Timer t3 = null;

        public DataChecker()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

            //
            // TODO: Add any constructor code after InitializeComponent call
            //

            t1 = new System.Threading.Timer(new TimerCallback(Timer_Callback), 'C', 0, 500);
            t2 = new System.Threading.Timer(new TimerCallback(Timer_Callback), 'T', 1, 500);
            t3 = new System.Threading.Timer(new TimerCallback(Timer_Callback), 'G', 2, 500);        

            /*WaitOrTimerCallback wotc = new WaitOrTimerCallback(GetData);
            AutoResetEvent are = new AutoResetEvent(false);
            ThreadPool.RegisterWaitForSingleObject(are, new WaitOrTimerCallback(GetData), 'C', 500, false);*/

        }

        protected void Timer_Callback(object state)
        {
            ThreadPool.QueueUserWorkItem(new WaitCallback(GetData), state);
        }


        int retVal;
        private void GetData(object type)
        {
            char priceType = (char)type;
            string sql = null;

            sql = "SELECT Price FROM tblPrices WHERE Type='"+priceType.ToString()+"'";

            SqlConnection cn = new SqlConnection("Server=localhost; Database=Prices; Integrated Security=SSPI");
            cn.Open();

            SqlCommand cmd = new SqlCommand(sql, cn);

            
            lock(this)
            {
                retVal = (int)cmd.ExecuteScalar(); 
                switch(priceType) 
                {
                    case 'C':
                        lastCoffeePrice = Convert.ToInt32(txtCoffeePrice.Text);
                        txtCoffeePrice.Text = retVal.ToString();
                        break;
                    case 'T':
                        lastTeaPrice = Convert.ToInt32(txtTeaPrice.Text);
                        txtTeaPrice.Text = retVal.ToString();
                        break;
                    case 'G':
                        lastGoldPrice = Convert.ToInt32(txtGoldPrice.Text);
                        txtGoldPrice.Text = retVal.ToString();
                        break;
                }
            }
            

            allUpdates++;
            cn.Close();
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.txtCoffeePrice = new System.Windows.Forms.TextBox();
            this.txtTeaPrice = new System.Windows.Forms.TextBox();
            this.txtGoldPrice = new System.Windows.Forms.TextBox();
            this.lblCoffeePrice = new System.Windows.Forms.Label();
            this.lblTeaPrice = new System.Windows.Forms.Label();
            this.lblGoldPrice = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // txtCoffeePrice
            // 
            this.txtCoffeePrice.Location = new System.Drawing.Point(72, 24);
            this.txtCoffeePrice.Name = "txtCoffeePrice";
            this.txtCoffeePrice.TabIndex = 0;
            this.txtCoffeePrice.Text = "0";
            // 
            // txtTeaPrice
            // 
            this.txtTeaPrice.Location = new System.Drawing.Point(192, 24);
            this.txtTeaPrice.Name = "txtTeaPrice";
            this.txtTeaPrice.TabIndex = 1;
            this.txtTeaPrice.Text = "0";
            // 
            // txtGoldPrice
            // 
            this.txtGoldPrice.Location = new System.Drawing.Point(312, 24);
            this.txtGoldPrice.Name = "txtGoldPrice";
            this.txtGoldPrice.TabIndex = 2;
            this.txtGoldPrice.Text = "0";
            // 
            // lblCoffeePrice
            // 
            this.lblCoffeePrice.Location = new System.Drawing.Point(72, 0);
            this.lblCoffeePrice.Name = "lblCoffeePrice";
            this.lblCoffeePrice.TabIndex = 3;
            this.lblCoffeePrice.Text = "Coffee Price";
            // 
            // lblTeaPrice
            // 
            this.lblTeaPrice.Location = new System.Drawing.Point(192, 0);
            this.lblTeaPrice.Name = "lblTeaPrice";
            this.lblTeaPrice.TabIndex = 4;
            this.lblTeaPrice.Text = "Tea Price";
            // 
            // lblGoldPrice
            // 
            this.lblGoldPrice.Location = new System.Drawing.Point(320, 0);
            this.lblGoldPrice.Name = "lblGoldPrice";
            this.lblGoldPrice.TabIndex = 5;
            this.lblGoldPrice.Text = "Gold Price";
            // 
            // DataChecker
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(424, 54);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                          this.lblGoldPrice,
                                                                          this.lblTeaPrice,
                                                                          this.lblCoffeePrice,
                                                                          this.txtGoldPrice,
                                                                          this.txtTeaPrice,
                                                                          this.txtCoffeePrice});
            this.MaximizeBox = false;
            this.Name = "DataChecker";
            this.Text = "Data Checker";
            this.ResumeLayout(false);

        }
        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() 
        {
            Application.Run(new DataChecker());
        }

        
    }
}