http://www.junnark.com/Articles/Build-a-Web-Chat-Application-Using-ASP-Net-LINQ-and-AJAX-CS.aspx
chatroom.aspx.cs
ublic partial class ChatRoom : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler
{
Class1 obj = new Class1();
private string _callBackStatus;
// this.InsertMessage(ConfigurationManager.AppSettings["ChatLoggedInText"] + " " + DateTime.Now.ToString());
private void GetLoggedInUsers()
{
LinqChatDataContext db = new LinqChatDataContext();
// let's check if this authenticated user exist in the
// LoggedInUser table (means user is logged-in to this room)
var user = (from u in db.LoggedInUsers
where u.UserID == Convert.ToInt32(Session["ChatUserID"])
&& u.RoomID == Convert.ToInt32(lblRoomId.Text)
select u).SingleOrDefault();
// if user does not exist in the LoggedInUser table
// then let's add/insert the user to the table
if (user == null)
{
LoggedInUser loggedInUser = new LoggedInUser();
loggedInUser.UserID = Convert.ToInt32(Session["ChatUserID"]);
loggedInUser.RoomID = Convert.ToInt32(lblRoomId.Text);
db.LoggedInUsers.InsertOnSubmit(loggedInUser);
db.SubmitChanges();
}
string userIcon;
StringBuilder sb = new StringBuilder();
// get all logged in users to this room
var loggedInUsers = from l in db.LoggedInUsers
where l.RoomID == Convert.ToInt32(lblRoomId.Text)
select l;
// list all logged in chat users in the user list
foreach (var loggedInUser in loggedInUsers)
{
// show user icon based on sex
if (loggedInUser.Usertab.Sex.ToString().ToLower() == "m")
userIcon = "<img src='Images/manIcon.gif' style='vertical-align:middle' alt=''> ";
else
userIcon = "<img src='Images/womanIcon.gif' style='vertical-align:middle' alt=''> ";
if (loggedInUser.Usertab.Username != (string)Session["ChatUsername"])
sb.Append(userIcon + "<a href=#>" + loggedInUser.Usertab.Username + "</a><br>");
else
sb.Append(userIcon + "<b>" + loggedInUser.Usertab.Username + "</b><br>");
}
// holds the names of the users shown in the chatroom
litUsers.Text = sb.ToString();
}
private void InsertMessage(string text)
{
LinqChatDataContext db = new LinqChatDataContext();
Message message = new Message();
message.RoomID = Convert.ToInt32(lblRoomId.Text);
message.UserID= Convert.ToInt32(Session["ChatUserID"]);
if (String.IsNullOrEmpty(text))
{
message.Text = txtMessage.Text.Replace("<", "");
message.Color = ddlColor.SelectedValue;
}
else
{
message.Text = text;
message.Color = "gray";
}
message.ToUserID = null; // in the future, we will use this value for private messages
message.TimeStamp = DateTime.Now;
db.Messages.InsertOnSubmit(message);
db.SubmitChanges();
}
private void GetRoomInformation()
{
// get the room information from the database
// we're going to set this up so that we can use
// many rooms if we want to
LinqChatDataContext db = new LinqChatDataContext();
var room = (from r in db.Rooms
where r.RoomID == Convert.ToInt32(lblRoomId.Text)
select r).SingleOrDefault();
lblRoomId.Text = room.RoomID.ToString();
lblRoomName.Text = room.Name;
}
//this.InsertMessage(ConfigurationManager.AppSettings["ChatLoggedInText"] + " " + DateTime.Now.ToString())
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string roomId = (string)Request["roomId"];
lblRoomId.Text = roomId;
this.GetRoomInformation();
this.GetLoggedInUsers();
this.InsertMessage(ConfigurationManager.AppSettings["ChatLoggedInText"] + " " + DateTime.Now.ToString());
this.GetMessages();
// create a call back reference so we can log-out user when user closes the browser
string callBackReference = Page.ClientScript.GetCallbackEventReference(this, "arg", "LogOutUser", "");
string logOutUserCallBackScript = "function LogOutUserCallBack(arg, context) { " + callBackReference + "; }";
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "LogOutUserCallBack", logOutUserCallBackScript, true);
}
}
void System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent(string eventArgument)
{
_callBackStatus = "failed";
// log out the user by deleting from the LoggedInUser table
string callBackReference = Page.ClientScript.GetCallbackEventReference(this, "arg", "LogOutUser", "");
string logOutUserCallBackScript = "function LogOutUserCallBack(arg, context) { " + callBackReference + "; }";
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "LogOutUserCallBack", logOutUserCallBackScript, true); LinqChatDataContext db = new LinqChatDataContext();
var loggedInUser = (from l in db.LoggedInUsers
where l.UserID == Convert.ToInt32(Session["ChatUserID"])
&& l.RoomID == Convert.ToInt32(lblRoomId.Text)
select l).SingleOrDefault();
db.LoggedInUsers.DeleteOnSubmit(loggedInUser);
db.SubmitChanges();
// insert a message that this user has logged out
this.InsertMessage("Just logged out! " + DateTime.Now.ToString());
_callBackStatus = "success";
}
private void GetMessages()
{
LinqChatDataContext db = new LinqChatDataContext();
var messages = (from m in db.Messages
where m.RoomID == Convert.ToInt32(lblRoomId.Text)
orderby m.TimeStamp descending
select m).Take(20).OrderBy(m => m.TimeStamp);
if (messages != null)
{
StringBuilder sb = new StringBuilder();
int ctr = 0; // toggle counter for alternating color
foreach (var message in messages)
{
// alternate background color on messages
if (ctr == 0)
{
sb.Append("<div style='padding: 10px;'>");
ctr = 1;
}
else
{
sb.Append("<div style='background-color: #EFEFEF; padding: 10px;'>");
ctr = 0;
}
if (message.Usertab.Sex.ToString().ToLower() == "m")
sb.Append("<img src='Images/manIcon.gif' style='vertical-align:middle' alt=''> " + message.Text + "</div>");
else
sb.Append("<img src='Images/womanIcon.gif' style='vertical-align:middle' alt=''> " + message.Text + "</div>");
}
litMessages.Text = sb.ToString();
}
}
protected void BtnSend_Click(object sender, EventArgs e)
{
if (txtMessage.Text.Length > 0)
{
this.InsertMessages(null);
this.GetMessages();
txtMessage.Text = String.Empty;
ScriptManager1.SetFocus(txtMessage.ClientID);
}
}
private void InsertMessages(string text)
{
LinqChatDataContext db = new LinqChatDataContext();
Message message = new Message();
message.RoomID = Convert.ToInt32(lblRoomId.Text);
message.UserID = Convert.ToInt32(Session["ChatUserID"]);
if (String.IsNullOrEmpty(text))
{
message.Text = txtMessage.Text.Replace("<", "");
message.Color = ddlColor.SelectedValue;
}
else
{
message.Text = text;
message.Color = "gray";
}
message.ToUserID = null; // in the future, we will use this value for private messages
message.TimeStamp = DateTime.Now;
db.Messages.InsertOnSubmit(message);
db.SubmitChanges();
}
protected void Timer1_OnTick(object sender, EventArgs e)
{
this.GetLoggedInUsers();
this.GetMessages();
if ((string)Session["IsChatroomInFocus"] == null)
ScriptManager1.SetFocus(txtMessage);
}
protected void BtnLogOut_Click(object sender, EventArgs e)
{
LinqChatDataContext db = new LinqChatDataContext();
var loggedInUser = (from l in db.LoggedInUsers
where l.UserID == Convert.ToInt32(Session["ChatUserID"])
&& l.RoomID == Convert.ToInt32(lblRoomId.Text)
select l).SingleOrDefault();
db.LoggedInUsers.DeleteOnSubmit(loggedInUser);
db.SubmitChanges();
// insert a message that this user has logged out
this.InsertMessage("Just logged out! " + DateTime.Now.ToString());
// clean the session
Session.RemoveAll();
Session.Abandon();
// redirect the user to the login page
Response.Redirect("Default.aspx");
}
string System.Web.UI.ICallbackEventHandler.GetCallbackResult()
{
return _callBackStatus;
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
//obj.gettable("select * from Usertab where UserID=" + DropDownList1.SelectedItem.Value + "");
//if(obj.dt.Rows.Count>0)
//{
//}
}
}
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