Re: delegate thru an interface - C# Discussion Boards

Ankit Aneja9-Mar-06 19:33

9-Mar-06 19:33

<%@ Import Namespace="System.Data" %>

DataView CartView;
Double runningTotal = 0;

//Cart is a property on the Page
DataTable Cart {
get {
if (Session["DGC_ShoppingCart"] == null) {
DataTable tmpCart = new DataTable();
tmpCart.Columns.Add(new DataColumn("Qty", typeof(string)));
tmpCart.Columns.Add(new DataColumn("Product", typeof(string)));
tmpCart.Columns.Add(new DataColumn("Price", typeof(Double)));
tmpCart.Columns.Add(new DataColumn("GiftWrap", typeof(bool)));
Session["DGC_ShoppingCart"] = tmpCart;

// first load -- prepopulate with some data
for (int i=1; i<=6; i++) {
DataRow dr = tmpCart.NewRow();
dr[0] = "1";
dr[1] = "Product " + i.ToString();
dr[2] = 1.23 * (i+1);
dr[3] = false;
tmpCart.Rows.Add(dr);
}
return tmpCart;
}
else
return (DataTable)Session["DGC_ShoppingCart"];
}
}

void Page_Init(Object sender, EventArgs e) {
MyDataGrid.EnableViewState=true;
}

void Page_Load(Object sender, EventArgs e) {
CartView = Cart.DefaultView;
if (!IsPostBack)
BindGrid();
}

void BindGrid() {
MyDataGrid.DataSource = CartView;
MyDataGrid.DataBind();
}

void btnUpdate_click(Object sender, EventArgs e) {

for (int i=0; i<MyDataGrid.Items.Count; i++) {

DataGridItem _item = MyDataGrid.Items[i];
TextBox qtyTextBox = (TextBox)_item.FindControl("txtQty");
CheckBox giftCheckBox = (CheckBox)_item.FindControl("chkGift");

// with a database, we'd use an update command.
// since this is an in-memory datatable, we'll just change the in-memory row.
DataRow dr = Cart.Rows[i];
dr[0] = qtyTextBox.Text;
dr[3] = giftCheckBox.Checked;
}
BindGrid();
}

Double CalcTotal (int count, Double price) {
Double total = count * price;
runningTotal += total;

return(total);
}

Custom Editing with DataGrid

<asp:datagrid id="MyDataGrid" runat="server"
="" bordercolor="black" borderwidth="1" gridlines="none" cellpadding="4" font-name="Verdana" font-size="8pt" headerstyle-backcolor="#aaaadd" autogeneratecolumns="false">
<columns>
<asp:templatecolumn headertext="Quantity">
<itemtemplate>
<asp:textbox id="txtQty" runat="server"
="" text="<%# DataBinder.Eval(Container, "DataItem.Qty") %>" width="40px">

<asp:boundcolumn headertext="Product" datafield="Product">
<asp:boundcolumn headertext="Price" datafield="Price" dataformatstring="{0:c}">
<asp:templatecolumn headertext="Gift Wrap?">
<itemtemplate>

<asp:checkbox id="chkGift" runat="server"
="" checked="<%# (bool)(((DataRowView)Container.DataItem)["GiftWrap"]) %>">

<asp:templatecolumn headertext="SubTotal">
<itemtemplate>

<asp:label runat="server"
="" text="<%# String.Format("{0:c}",CalcTotal((Int32.Parse((string)(((DataRowView)Container.DataItem)["Qty"]))),((Double)(((DataRowView)Container.DataItem)["Price"])))) %>">

<asp:label runat="server"
="" text="<%# String.Format("{0:c}", runningTotal) %></b>">

<asp:linkbutton id="btnUpdate" runat="server"
="" text="Update Totals" font-name="Verdana" font-size="8pt" onclick="btnUpdate_click">

Ankit Aneja
"Nothing is impossible. The word itself says - I M possible"

Clear buffer

hung_ngole9-Mar-06 4:32

hung_ngole

9-Mar-06 4:32

Console.Write(".............");
x = Console.Read();
Console.Write(".............");
y = Console.Read();

When using above code, the second Console.Read() has been done automatically caused by the "Enter key" of the first one.

How can I solve this problem? How can I clear buffer of keyboard??

Hung

Re: Clear buffer

leppie9-Mar-06 4:34

leppie

9-Mar-06 4:34

Use Console.ReadLine()

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Re: Clear buffer

hung_ngole9-Mar-06 4:52

hung_ngole

9-Mar-06 4:52

I appreciate your solution, but I want to use the Console.Read() for some purposes.
Do you have others solution???????

Hung

where to download Longhorn SDK

Sheel Gohe9-Mar-06 3:27

Sheel Gohe

9-Mar-06 3:27

Can anyone plz tell me where can i download "longhorn SDK" not Longhorn OS.
Plz give me any link if you have. Unsure | :~

Thanks in advance
Sheel

Sheel Gohe

Re: where to download Longhorn SDK

gnjunge9-Mar-06 3:35

gnjunge

9-Mar-06 3:35

Longhorn is now called Vista and you can get its SDK at http://msdn.microsoft.com/windowsvista/getthebeta/[^]

delegate thru an interface

spin vector9-Mar-06 3:17

spin vector

9-Mar-06 3:17

I am defining an interface to a real-time engine. Based on inputs to the engine the engine may fire events. How do I build the code so that the eventhandler is on the other side of the interface from the engine? That is, my subscriber(s) is external to the engine. Seems to me I have to declare something in the interface specification.

Thanks.

Re: delegate thru an interface

leppie9-Mar-06 4:42

leppie

9-Mar-06 4:42

If you are already defining an interface, events arent necessary. You simply call the methods on the interface and let the implemeter handle them. IMO better than the event approach, and alot faster due to direct calls. Smile | :)

Events in an interface is normally so the interface can 'notify' to the interface user.

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Re: delegate thru an interface

spin vector9-Mar-06 5:02

spin vector

9-Mar-06 5:02

Consider this diagram:

user <- interface -> engine

Based on your last e-mail, the target of the event within the engine is on the interface. How is it that the user is notified?

Re: delegate thru an interface

vineas9-Mar-06 8:26

vineas

9-Mar-06 8:26

I think he's confused about your use of the word interface - he's thinking of an interface such as IDisposable, or ISerializable (though obviously defined by you), and it sounds like you mean interface as object layer that hides the engine.

Off the top of my head, I can think of two ways to do this:

1) Cascading events - When the interface is loaded, it subscribes to events in the engine. When the user connects to the interface, it then subscribes to events in the interface. When the engine raises the event, the interface gets notified to it's handler. It then raises the event the user subscribed to.

These cascading events will work, though performance may be a concern to you. It wasn't in an app I'm working on (at least in this area), and the events needed to be bubbled up quite a few layers, with each layer doing something with the event, so this mechanism worked fairly well.

2) Have a method defined in your interface that takes in a delegate as a parameter of the correct delegate type to the event you want to subscribe to. This interface method will use this delegate to subscribe to the engine event. When the engine raises the event, the user is notified without the interface getting in the way.

<br />
// in interface<br />
public void ConnectEvent(EventHandler h)<br />
{<br />
  engine->TheEvent += h;<br />
}<br />
<br />
...<br />
// in user<br />
  interface->ConnectEvent(new EventHandler(user_EventHandler));<br />

I did something like this a while ago, but I don't remember why or how well it worked out.

-----
In the land of the blind, the one eyed man is king.

How to get window's size and position to javascript?

jzb9-Mar-06 3:05

jzb

9-Mar-06 3:05

How to get window's size and position to javascript?

BreakPoint

Areff9-Mar-06 2:29

Areff

9-Mar-06 2:29

Hi, evrybody
---------
what is doing BreakPoint In C# Code?
Why we use BreakPoint ?
---------

---------------------
Areff Bahrami(KAVEH)
Areff.HB@Gmail.com
---------------------

Re: BreakPoint

Dan Neely9-Mar-06 3:03

Dan Neely

9-Mar-06 3:03

it's used for debugging. You put one prior to where you have a peice of code that isn't working. When the program gets to that point it stops running and goes to the IDE where you can step through the code one line at a time to see what's going on.

Re: BreakPoint

Areff9-Mar-06 19:58

Areff

9-Mar-06 19:58

thanks

---------------------
Areff Bahrami(KAVEH)
Areff.HB@Gmail.com
---------------------

socket programming

eey569-Mar-06 0:52

eey56

9-Mar-06 0:52

make socket programming to use fifo (first in first out) and round robin algorithm.(lots of client and one destination)(source code)

Re: socket programming

Divyang Mithaiwala9-Mar-06 2:50

Divyang Mithaiwala

9-Mar-06 2:50

Is it question of advertize if any article?

Divyang Mithaiwala
System Engineer & Software Developer

Re: socket programming

eey569-Mar-06 3:20

eey56

9-Mar-06 3:20

question,how do I make socket programming to use fifo and round robin algorithm for one destination to lots of clients.if you know source code and send me,I will be very happy Smile | :)

.Or an internet address about its source code.
Thank you...

Re: socket programming

Divyang Mithaiwala9-Mar-06 4:10

Divyang Mithaiwala

9-Mar-06 4:10

Hello eey56,

See some links if you found usefull.

http://www.codeproject.com/csharp/testingsocketservers.asp[^]
http://www.codeproject.com/csharp/socketsincsharp.asp[^]
http://www.codeproject.com/csharp/binarydatausingsocket.asp[^]
http://www.codeproject.com/csharp/chandrasekar.asp[^]

Divyang Mithaiwala
System Engineer & Software Developer

Re: socket programming

eey569-Mar-06 10:20

eey56

9-Mar-06 10:20

thank you for your helpfulness Smile | :)

Re: socket programming

eey569-Mar-06 3:17

eey56

9-Mar-06 3:17

question,how do I make socket programming to use fifo and round robin algorithm for one destination to lots of clients.if you know source code and send me,I will be very happy Smile | :)

.Or an internet address about its source code.
Thank you...

What C# compiler does?

Chandana Subasinghe9-Mar-06 0:40

Chandana Subasinghe

9-Mar-06 0:40

Does any body know what tasks do C# compiler when compile code in to the MSIL?
Thank you.

Re: What C# compiler does?

leppie9-Mar-06 4:33

leppie

9-Mar-06 4:33

There are 3 open source C# compilers, why dont you look?

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MultiThreading

AB77719-Mar-06 0:24

AB7771

9-Mar-06 0:24

HI all,

i have created an MDI Application
i have created some threads in one of the forms
now when all the threads finish their processing
an exception is thrown by the application saying
"System.NullReferenceException
Object reference not set to an instance of an object"

and this exception is thrown by the main MDI form

i don't know what's going wrong where.

It will be great if some one could tell me the solution to this problem

Thanks,
Pramod

Re: MultiThreading

Steve Hansen9-Mar-06 0:42

Steve Hansen

9-Mar-06 0:42

It would be usefull to post some code, run in debug and see where it happens.
At least check the Stack Trace in the exception and show the code from the method where it happens.

Re: MultiThreading

AB77719-Mar-06 1:07

AB7771

9-Mar-06 1:07

i have created all the threads on the click of a button
when the control returns after finishing all the threads
the exception is raised

Why is this exception raised?
is there anything to be done when the threads are finished with processing
and the control is returned from where they were spawned?

Thanks,
Pramod

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.