?using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class chat : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            Application.Lock();
            string[] user = (string[])Application["user"];
            Application.UnLock();
            for (int i = 0; i < user.Length; i++)
            {

                this.lbUser.Items.Add(user[i]);
            }
            Application.Lock();
            string[] user1 = (string[])Application["user"];
            Application.UnLock();
            int k = 0;
            int length = 0;
            while (user1[k] != null)
            {
                length++;
                k++;

            }
            for (int j = 0; j < length; j++)
            {
                this.ddlUser.Items.Add(user1[j]);
            }
            Application.Lock();
            string[] message = (string[])Application["message"];
            int a = 0;
            int b = 0;
            while (message[a] != null)
            {
                b++;
                a++;

            }
            string info = null;
            for (int c = 0; c < b; c++)
            {
                info =  info + message[c] + "\n";

            }
            Application.UnLock();
            this.txtInfo.Text = info;
            
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string userName = (string)Session["userName"];
        Session.Clear();
        Application.Lock();
        string[] user = (string[])Application["user"];
        int i = 0;
        int length = 0;
        while (user[i] != null)
        {
            length++;
            i++;
        }
        for (i = 0; i < length; i++)
        {
            if (user[i].Equals(userName))
            {
                for (int j = i; j < length; j++)
                {
                    user[j] = user[j + 1];
                }
            }
        }
        Application.Add("user", user);
        Application.UnLock();
        this.lbUser.Items.Remove(userName);
    }
    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        string message = (string)Session["userName"] + "對" + this.ddlUser.Text + "說:" + txtMessage.Text;
        Application.Lock();
        string[] message1 = (string[])Application["message"];
        int i = 0;
        int length = 0;
        while (message1[i] != null)
        {
            length++;
            i++;

        }
        message1[i] = message;
        Application.Add("message", message);
        Application.UnLock();
        Application.Lock();
        string[] message2 = (string[])Application["message"];
        int a = 0;
        int b = 0;
        while (message2[a] != null)
        {
            b++;
            a++;

        }
        string info = null;
        for (int c = 0; c < b; c++)
        {
            info = info + message2[c] + "\n";

        }
        Application.UnLock();
        this.txtInfo.Text = info;
        

    }
}