Re: Tele-type screen saver - C# Discussion Boards

19-Jun-08 9:32

So I've been trying to create a screen saver where the contents of a file will be read and displayed on the screen - but not having much success.

I want the text to appear one character at a time (like a typewriter) but the problem is the flicker! I've tried labels, multi-line textboxes and richtextboxes and they all have ridiculous amounts of flicker. Labels are better if I don't set the FlatStyle to System but then I can't see the tabs, so I don't want that.

Another issue is I'm not able to scroll along with the text as it progresses down the control. I tried the ScrollToCaret trick and that works but first it has to jump to the start of the control which causes another undesirable effect.

Here's the method that does the typewriter thing:

public void TW()
{
try
{
char[] myChars = msg.ToCharArray();
lbl.Text = "";
for(int i = 0; i < myChars.Length; i++)
{
lbl.Text += myChars[i].ToString();
System.Threading.Thread.Sleep(0);
}

}
catch(Exception)
{

}
}

Spacix One19-Jun-08 9:42

Spacix One

19-Jun-08 9:42

Have you tried GDI+ and/or direct draw

-Spacix
All your skynet questions[^] belong to solved

I dislike the black-and-white voting system on questions/answers. Dead | X|

Elvis_Pretzelator19-Jun-08 9:47

19-Jun-08 9:47

No I haven't. I think once I made a triangle in some tutorial somewhere, but that's it. Would this work for text pulled from a file?

Spacix One19-Jun-08 10:19

Spacix One

19-Jun-08 10:19

yep, you can read the text into a string and load string builder then draw is one char at a time, or any other goodies you wish to manipulate it with.

-Spacix
All your skynet questions[^] belong to solved

I dislike the black-and-white voting system on questions/answers. Dead | X|

Elvis_Pretzelator25-Jun-08 10:02

25-Jun-08 10:02

Well the GDI+ suggestion works great!! No flicker and it looks very nice. Now I'm wondering how I clear the screen and "tele-type" some more text.

The graphics object I'm using comes from the main form's CreateGraphics method. I have no idea if this is ideal or not (probably not) but I'm not sure how I could clear the form once the bottom of the screen is reached and continue from the top with the remainder of the text.

Part of the problem might be that the method used to write my text is in another thread.

Elvis_Pretzelator26-Jun-08 5:39

C# Thread termination issue

26-Jun-08 5:39

Never mind - I got it. After the text has finished I just call the graphic's FillRectangle() method and fill it with the background color.

Also, while the text is printing I test the height of the VisibleClipBounds and if my text has grown too big then I clear the screen and continue typing:

while(true)
				{
					string result = "";
					for(int i = 0; i < characters.Length; i++)
					{
						// Concatenate the string to create
						// a "tele-type" like effect.
						result += characters[i].ToString();
						gfx.DrawString(result, lucindaFont, green, 10, 10);
						Thread.Sleep(1);
						
						
						// If the string has gotten too big
						// for the visible display,
						// clear the screen and continue
						// the string where we left off.
						SizeF size = gfx.MeasureString(result, lucindaFont);
						if(gfx.VisibleClipBounds.Size.Height < size.Height)
						{
							gfx.FillRectangle(black, gfx.VisibleClipBounds);
							result = "";
						}
					}
					// Start fresh once the string is complete.
					gfx.FillRectangle(black, gfx.VisibleClipBounds);
				}

Merlock219-Jun-08 8:39

Merlock2

19-Jun-08 8:39

Hey everyone,

I have recently built a client and server application for transferring files across the network. The client application uses two threads: one for transferring file data to the server and another for monitoring incoming messages from the server. Both threads use separate NetworkStream objects for their respewctive tasks.
The job of the listener thread is to listen for messages from the server (which are in the from of strings). Now, when the server disconnects for whatever reason, it'll send a "Disconnect" string message to the client. The listener thread will receive that message, interpret it, and then tell the client application to disconnect from the server.

to illustrate what I mean, here is some code from my client:

//the thread monitoring incoming messages from the server
private Thread m_oListenerThread;

//the thread in charge of file transfer
private Thread m_oTransferThread;

//when 'true', the listener thread exits its loop and terminates
private volatile bool m_bListenerStop;

//when 'true', the transfer thread exits its loop and terminates
private volatile bool m_bTransferThreadStop;

//here is the method run by the listener thread:
StartListening()
{
//some initialization details here
//...
while(m_bListenerStop)
{
//check the NetworkStream object for any data
//...

//if data available, extract string from NetworkStream
//...

//parse message (where sMessage is the extracted string message)
HandleCommand(sMessage);

}
//thread termination details
//...
}

HandleCommand(string z_sMessage)
{
if (z_sMessage == "Disconnect")
{
DisconnectFromServer();
}
}

This is simple enough, but in order to make the application more robust, I need to ensure that all threads have terminated. The only way I know of so far is to call Join(nMiliseconds) on the thread which you want to test. This will cause the calling thread (ex: main) to wait for the thread until nMiliseconds has expired, or the thread is no longer active. Therefore, the DisconnectFromServer() method would look something like this:

DisconnectFromServer()
{
//signal threads to terminate
m_bListenerStop = true;
m_bTransferThreadStop = true;

//close all connection elements
//...

//ensure all threads have stopped
if (m_oListenerThread != null)
{
UpdateStatusDisplay("Waiting for listener thread to terminate...");

//wait for 302 milliseconds for listener thread to terminate. If the thread has not terminated
//by that time, abort thread and throw an exception.
if (m_oListenerThread.Join(302) == false)
{
m_oListenerThread.Abort();
}

if (m_oTransferThread != null)
{

//wait 20 ms for transfer thread to terminate. If the thread has not terminated by that time, abort thread and throw exception.
if (m_oTransferThread.Join(20) == false)
{
m_oTransferThread.Abort();
}
}

//some other termination logic
//...

}

so when x miliseconds has expired and the given thread is not terminated, Abort() is called on the thread to force it to shut down. The problem with the following is that when DisconnectFromServer is called by the listener thread (via HandleCommand()), the thread waits for the function to return so it may keep going and eventually exit its while loop. But it can never do this since DisconnectFromServer() will make it block (due to Join()). The thread is therefore stuck waiting for itself. When the time expires, it simply shuts itself down (using Abort()), and the function never returns, just abruptly stops.
This simply won't do! I have tried using an event in the hopes that the thread would fire a 'shutdown' event, and keep going while the main thread handles the event by calling DisconnectFromServer(), but the same problem arose: the thread waits for the event handler to return.
In short, is there a way to fire events or call methods without being forced to wait for those to return?
Or am I forced to create a third thread which would handle the shutdown procedure? Of course, if I do the latter, I won't really have any means to use Join() on that shutdown thread to make sure it terminated...

Help: I'm new to C#: I want to make a global function

TheFoZ19-Jun-08 8:27

TheFoZ

19-Jun-08 8:27

Hi
As you may be able to tell I am a bit new to C# and I may be attacking this from the wrong angle.

I would like to create global function for the program I am writing. I would like to group these functions together for ease i.e. Customer related functions, general function but enable them to be used by other bits of code. I can do this fine in VB.NET but cannot get them to work in C#.

For Example I would like a function that returns a string that is stripped of all punctuation and is in upper case. This would be a general function and I would like it in its own code file so I can group it together with other ones.

I've had a look in my book and cannot find anything that helps. Is this more of a VB thing and is done differently in C# or am I missing something.

ps I'm using C# 2005 Express Edition.

Many Thanks

The FoZ

Re: Help: I'm new to C#: I want to make a global function

Judah Gabriel Himango19-Jun-08 8:56

Judah Gabriel Himango

19-Jun-08 8:56

Customer-related functions should be instance methods on the Customer class.

For things that don't require an instance, make them static. For example,

public class MyGlobalFuncs
{
    public static void Foo() { }
}

That can be invoked like this: MyGlobalFuncs.Foo()

Life, family, faith: Give me a visit.

From my latest post: "A lot of Christians struggle, perhaps at a subconscious level, about the phrase "God of Israel". After all, Israel's God is the God of Judaism, is He not? And the God of Christianity is not the God of Judaism, right?"

Judah Himango

Re: Help: I'm new to C#: I want to make a global function

TheFoZ19-Jun-08 9:03

TheFoZ

19-Jun-08 9:03

Thanks for that. Its so easy when you know how!

Thanks again.

The FoZ

Re: Help: I'm new to C#: I want to make a global function

Guffa19-Jun-08 11:20

Guffa

19-Jun-08 11:20

TheFoZ wrote:
I would like to create global function

That is not possible. You can use static methods, as Judah suggested, but they are not global.

TheFoZ wrote:
I can do this fine in VB.NET

No, you can't. VB.NET doesn't have any global functions either. If you mean a module, that is just a class where all members automatically become static.

Despite everything, the person most likely to be fooling you next is yourself.

RadioButtonList

john3419-Jun-08 7:59

john34

19-Jun-08 7:59

Hi all,

I have a RadioButtonList attached to a data source and it works perfectly.
However, I have been asked if they can be standard buttons instead of radiobuttons.
What I would like to do is create my own control that inherits all the functionality of the radiobuttonList but renders buttons instead of radiobuttons?
Does anyone have any ideas how I can achieve this?

Thanks!!!
John

Building a System.Uri with a query string

Spacix One19-Jun-08 7:40

Spacix One

19-Jun-08 7:40

I give up, this seems impossible without the UriBuilder class... Well since .NET 1.1 when they made Uri(string, bool) obsolete... So here is my question:

How do you build a System.Uri object in .NET compact framework that points to a "file://" scheme with passed query information?

I've tried every valid (not obsolete) constructor for System.Uri meaning:

* Uri(string)
* Uri(string, UriKind)
* Uri(base, string)
* Uri(Uri, Uri)

It didn't matter which I use because they don't have any affect on the outcome... Every constructor will escape the ? to hex as %3F which is not valid to use with query information!!!

I can do this fine with strings but if I pass a string to the WebBrowser control it'll convert the string to a Uri object and have the problem again. So I need to build the correct Uri object and pass it to the WebBrowser control.

MSDN says the following lie:

http://msdn.microsoft.com/en-us/library/system.uri(VS.80).aspx[^] wrote:
The Uri constructors do not escape URI strings if the string is a well-formed URI including a scheme identifier.

Proven by this example:(start a new smart device application and add this code to the form1.cs file)

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Text; 
using System.Windows.Forms; 
 
namespace DeviceApplication1 
{ 
    public partial class Form1 : Form 
    { 
        public int demoValue = 4; 
        public Form1() 
        { 
            InitializeComponent(); 
            this.Load += new EventHandler(this.Form1_Load); 
        } 
 
        void Form1_Load(object sender, EventArgs e) 
        { 
            Uri htmlFile = new Uri(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), UriKind.Absolute); 
            MessageBox.Show("htmlFile.AbsoluteUri=\r\n" + htmlFile.AbsoluteUri); //show how the path is converted correctly into a uri string with a correct scheme 
            string properFormated = string.Format("{0}/DeviceApplication1/test.html?test={1}", htmlFile.AbsoluteUri, this.demoValue); 
            MessageBox.Show("properFormated=\r\n" + properFormated); //show the string is properly formated and escaped correctly! 
            Uri fileWithQuery = new Uri(properFormated); 
            MessageBox.Show("fileWithQuery.PathAndQuery=\r\n" + fileWithQuery.PathAndQuery); //show the error in the Uri not accepting the query content 
        } 
    } 
}

View your results and see my problem Frown | :(

any suggestions? I'm desprate at the moment (this has been bothering me since April!)

-Spacix
All your skynet questions[^] belong to solved

I dislike the black-and-white voting system on questions/answers. Dead | X|

Judah Gabriel Himango19-Jun-08 8:24

Judah Gabriel Himango

19-Jun-08 8:24

Also from the documentation:

"The URI represented by a Uri instance is always in "escaped" form. The following characters are reserved:

Semi-colon (";" )

Forward slash ( "/")

Question mark ( "?" )

Colon ( ":" )

At-sign ("@")

Ampersand ( "&" )

Equal sign ("=" )

Plus sign ("+" )

US Dollar sign ("$" )

Comma (",")

To transform the URI contained in a Uri instance from an escape encoded URI to a human-readable URI, use the System.Uri.ToString method."

Another thing you could do is call Uri.UnescapeDataString(someString), which will give you back your URI with the proper unescaped characters.

Spacix One19-Jun-08 9:06

Spacix One

19-Jun-08 9:06

Well I need the Uri object to pass to the WebBrowser control. If you pass it a string it'll convert it to a Uri object thus escaping the string it will navigate to.

In the Normal framework you can use UriBuilder to make a URL with extra unescaped information that is parsed properly by the .PathAndQuery property.

Example: (use a new c# console project on the normal framework 2.0 or higher)

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int demoValue = 4;
            UriBuilder ub = new UriBuilder("file://", "", -1, Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) + "/DeviceApplication1/test.html", string.Format("?test={0}", demoValue));
            Console.WriteLine("Correct OutPut:\r\n{0}", ub.ToString()); //show path and query content (without errors)
            Console.ReadLine();
        }
    }
}

-Spacix
All your skynet questions[^] belong to solved

I dislike the black-and-white voting system on questions/answers. Dead | X|

Judah Gabriel Himango19-Jun-08 11:05

Judah Gabriel Himango

19-Jun-08 11:05

It's amazing I've gone so long without knowing about UriBuilder. Thanks for that.

So your issue is only with the .NET Compact Framework? Interesting. I'm afraid I don't have an answer for this. Have you tried asking at the Mobile Development[^] forums? If this turns out to be a bug in the .NET Compact Framework, you ought to report this to the Microsoft Connect site.