Access Web Services Asynchronously in .NET Design Patterns

using System;
using System.Windows.Forms;
using System.Net;
using System.Runtime.Remoting.Messaging;
using WsClient1.WsTestRef1;

namespace WsClient1
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Button buttonCancel;
        private System.Windows.Forms.Button buttonGetQuote;
        private System.Windows.Forms.TextBox textBoxResult;
        private System.Windows.Forms.ComboBox comboBoxSymb;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.TextBox textBoxTimeout;
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;

        long _tmStart;
        private Service _wsProxy1;

        public Form1()
        {
            InitializeComponent();
            comboBoxSymb.SelectedIndex = 0;
        }

        /// <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.label1 = new System.Windows.Forms.Label();
			this.buttonCancel = new System.Windows.Forms.Button();
			this.comboBoxSymb = new System.Windows.Forms.ComboBox();
			this.buttonGetQuote = new System.Windows.Forms.Button();
			this.textBoxResult = new System.Windows.Forms.TextBox();
			this.label2 = new System.Windows.Forms.Label();
			this.textBoxTimeout = new System.Windows.Forms.TextBox();
			this.SuspendLayout();
			// 
			// label1
			// 
			this.label1.Location = new System.Drawing.Point(8, 16);
			this.label1.Name = "label1";
			this.label1.Size = new System.Drawing.Size(80, 16);
			this.label1.TabIndex = 0;
			this.label1.Text = "Stock Symbol:";
			// 
			// buttonCancel
			// 
			this.buttonCancel.Location = new System.Drawing.Point(176, 40);
			this.buttonCancel.Name = "buttonCancel";
			this.buttonCancel.Size = new System.Drawing.Size(80, 24);
			this.buttonCancel.TabIndex = 4;
			this.buttonCancel.Text = "Cancel";
			this.buttonCancel.Click += new System.EventHandler(this.buttonCancel_Click);
			// 
			// comboBoxSymb
			// 
			this.comboBoxSymb.Items.AddRange(new object[] {
															  "ELNK",
															  "MSFT",
															  "IBM",
															  "GOOG",
															  "SUNW"});
			this.comboBoxSymb.Location = new System.Drawing.Point(88, 11);
			this.comboBoxSymb.Name = "comboBoxSymb";
			this.comboBoxSymb.Size = new System.Drawing.Size(80, 21);
			this.comboBoxSymb.TabIndex = 5;
			this.comboBoxSymb.TextChanged += new System.EventHandler(this.comboBoxSymb_TextChanged);
			this.comboBoxSymb.SelectedIndexChanged += new System.EventHandler(this.comboBoxSymb_SelectedIndexChanged);
			// 
			// buttonGetQuote
			// 
			this.buttonGetQuote.Location = new System.Drawing.Point(176, 8);
			this.buttonGetQuote.Name = "buttonGetQuote";
			this.buttonGetQuote.Size = new System.Drawing.Size(80, 24);
			this.buttonGetQuote.TabIndex = 6;
			this.buttonGetQuote.Text = "Get Quote";
			this.buttonGetQuote.Click += new System.EventHandler(this.buttonGetQuote_Click);
			// 
			// textBoxResult
			// 
			this.textBoxResult.BackColor = System.Drawing.Color.FromArgb(((System.Byte)(255)), ((System.Byte)(255)), ((System.Byte)(192)));
			this.textBoxResult.BorderStyle = System.Windows.Forms.BorderStyle.None;
			this.textBoxResult.Location = new System.Drawing.Point(8, 72);
			this.textBoxResult.Name = "textBoxResult";
			this.textBoxResult.Size = new System.Drawing.Size(248, 13);
			this.textBoxResult.TabIndex = 7;
			this.textBoxResult.Text = "";
			// 
			// label2
			// 
			this.label2.Location = new System.Drawing.Point(8, 40);
			this.label2.Name = "label2";
			this.label2.Size = new System.Drawing.Size(80, 16);
			this.label2.TabIndex = 8;
			this.label2.Text = "Timeout (ms):";
			// 
			// textBoxTimeout
			// 
			this.textBoxTimeout.Location = new System.Drawing.Point(88, 40);
			this.textBoxTimeout.Name = "textBoxTimeout";
			this.textBoxTimeout.Size = new System.Drawing.Size(64, 20);
			this.textBoxTimeout.TabIndex = 9;
			this.textBoxTimeout.Text = "3000";
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(264, 92);
			this.Controls.Add(this.textBoxTimeout);
			this.Controls.Add(this.textBoxResult);
			this.Controls.Add(this.label2);
			this.Controls.Add(this.buttonGetQuote);
			this.Controls.Add(this.comboBoxSymb);
			this.Controls.Add(this.buttonCancel);
			this.Controls.Add(this.label1);
			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Fixed3D;
			this.Name = "Form1";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "Web Service Client1";
			this.ResumeLayout(false);

		}
		#endregion

        [STAThread]
        static void Main() 
        {
            Application.Run(new Form1());
        }

        private void comboBoxSymb_TextChanged(object sender, EventArgs e)
        {
            textBoxResult.Text = "";
        }

        private void comboBoxSymb_SelectedIndexChanged(object sender, EventArgs e)
        {
            textBoxResult.Text = "";
        }

        private void buttonGetQuote_Click(object sender, System.EventArgs e)
        {
			buttonGetQuote.Enabled = false;
            textBoxResult.Text = "";
            _tmStart = DateTime.Now.Ticks;

            string symbol = comboBoxSymb.Text.ToUpper();
            int timeout = int.Parse(textBoxTimeout.Text);
    
            _wsProxy1 = new Service();
            _wsProxy1.BeginGetStock(symbol, timeout, new AsyncCallback(OnGetStock), symbol);    
        }

        private void OnGetStock(IAsyncResult ar)
        {
            string symbol = (string)ar.AsyncState;
            string result;
            
            try 
            {
                double value = _wsProxy1.EndGetStock(ar);
                if (value ==0)
                    result = "Invalid, " + "'" +symbol +"'";
                else
                if (value <0)
                    result = "TimeOut, " + "[" +symbol +"]";
                else
                    result = "OK, " + value.ToString("F");
            }
            catch (WebException e)
            {
                if (e.Status == WebExceptionStatus.RequestCanceled)
                    result = "Cancelled, " + "<" +symbol +">";
                else
                    result = "Exception, " + e.Message;
            }
            catch (Exception e)
            {
                result = "Exception, " + e.Message;
            }

            //textBoxResult.Text = result + ",  (" + (DateTime.Now.Ticks -	 _tmStart) / 10000 + " ms)";
            textBoxResult.Invoke(new ShowResultDelegate(ShowResult), new object[] { result });
            _wsProxy1 = null;
			buttonGetQuote.Enabled = true;
		}
            
        private void buttonCancel_Click(object sender, System.EventArgs e)
        {
            if (_wsProxy1 != null)
                _wsProxy1.Abort();
        }

        private delegate void ShowResultDelegate(string str);
        private void ShowResult(string str)
        {
            textBoxResult.Text = str + ",  (" + (DateTime.Now.Ticks - _tmStart) / 10000 + " ms)";
        }
    }
}