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i want to restrict my application to run only one instance at a time on one machine, is there any option or property which helps, i want to do this when creating a setup for my application.
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thanx , i've used mutex before but the problem is how to apply mutex on this application.what should be the critical area?
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How can I round a float to an integer?
If I do int i=(int)3.0f it's not good because if 3.0f is like 2.9999999 in memory, I'll get i=2, which is unacceptable. Math.Round only accepts doubles/decimals, which is not an option because I need a float.
Any idea?
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Tony_P wrote: If I do int i=(int)3.0f it's not good because if 3.0f is like 2.9999999
Have you tried it?
Tony_P wrote: Math.Round only accepts doubles/decimals, which is not an option because I need a float
So what? Casting a single to a double is lossless.
I think you're concerned about non-existent problems.
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I wrote a little application to try Remote Events
I have two versions of this application
The first one: both, server and the client are Console application
The first one is working fine
I did not write any methods in Client, just do the Console.Writeline()
The second : server is a console application and the client is winform application. I have problem with second:
The event riesed but this event need to update RichTextBox in my Main form
I get this exception:
Cross-thread operation not valid: Control 'rtb_in' accessed from a thread other than the thread it was created on.
I tryed many approuches nothing helped.
Please help me with this issue.
Here is my code sample
Server:
using REWFComm;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Serialization.Formatters;
using System.Collections;
using System.Reflection;
namespace Server
{
class ServerRemote : MarshalByRefObject, ICommon
{
public void Message(string passed, object Client)
{
Console.WriteLine(passed);
MessageEvent(passed + ": your message is arrived",Client);
}
public event MessageHandler MessageEvent;
}
class Server
{
static void Main(string[] args)
{
Console.WriteLine("Server started\nListening...");
BinaryServerFormatterSinkProvider serverProvider = new BinaryServerFormatterSinkProvider();
serverProvider.TypeFilterLevel = TypeFilterLevel.Full;
IDictionary props = new Hashtable();
props["port"] = 8888;
props["typeFilterLevel"] = TypeFilterLevel.Full;
TcpChannel chan = new TcpChannel(props, null, serverProvider);
ChannelServices.RegisterChannel(chan, false);
RemotingConfiguration.RegisterWellKnownServiceType(typeof(ServerRemote),
"ServerRemote",
WellKnownObjectMode.Singleton);
Console.ReadLine();
}
}
}
Common object:
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.ComponentModel;
namespace REWFComm
{
public delegate void MessageHandler(string myStr, object Sender);
public interface ICommon
{
void Message(string passed, object Sender);
event MessageHandler MessageEvent;
}
public class Messages : MarshalByRefObject
{
public void MessageArrived(string myStr, object Sender)
{
((RichTextBox)Sender).AppendText(myStr); //-- HERE I GET THE EXCEPTION!!!!!
}
}
}
Client:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using REWFComm;
namespace Client
{
public partial class Main : Form
{
object formobj;
public Main()
{
InitializeComponent();
formobj = this.rtb_in;
}
private void btn_send_Click(object sender, EventArgs e)
{
ICommon obj = (ICommon)Activator.GetObject(typeof(ICommon), "tcp://localhost:8888/ServerRemote");
Messages ms = new Messages();
obj.MessageEvent+=new MessageHandler(ms.MessageArrived);
obj.Message(tb_out.Text,formobj);
}
}
}
modified on Saturday, January 3, 2009 2:13 PM
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Hi,
the methods that get called by the other side are bound to be asynchronous with respect to your main
thread, hence they execute on a different thread; the same is true for most timers, for serial port
receive, etc.
And you are not allowed to touch any Controls (accessing properties, calling methods) from any thread
but the one that created the Control, which normally is the main or GUI thread.
To solve the problem the Control class offers InvokeRequired property and Invoke method.
If you are unfamiliar with them, look them up, there are plenty of examples around.
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Thanks to your replay
I tryed this approuch with Invoke and InvokeRequired
But it doesn't help
Maybe I did not undestand it well
If You can modefy my code you will help me a lot
Thanks
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You might show us the code with InvokeRequired/Invoke then...
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Here is my client with InvokeReguired/Invoke methods
That I need to write in my Common object
If You need all files I can send you
Thanks
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using REWFComm;
namespace Client
{
public partial class Main : Form
{
delegate void RTBUpdateDelegate(string strMess);
object formobj;
public Main()
{
InitializeComponent();
formobj = this.rtb_in;
}
private void btn_send_Click(object sender, EventArgs e)
{
ICommon obj = (ICommon)Activator.GetObject(typeof(ICommon), "tcp://localhost:8888/ServerRemote");
Messages ms = new Messages();
obj.MessageEvent+=new MessageHandler(ms.MessageArrived);
obj.Message(tb_out.Text,formobj);
}
public void UpdateRTB(string strMess)
{
if (rtb_in.InvokeRequired)
rtb_in.Invoke(new RTBUpdateDelegate(NowUpdateRTB), new object[] { strMess });
else
NowUpdateRTB(strMess);
}
private void NowUpdateRTB(string strMess)
{
rtb_in.AppendText(strMess + "\n");
}
}
}
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Hi,
the client code you now showed looks fine.
Except I see you are trying to pass rtb_in from client to server; I don't think that is possible.
If the server needs to modify rtb_in at the client, it should not try and do that itself, instead
it should tell the client to modify it.
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This is a problem
How can I tell the client to modify?
Here is Common object code:
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.ComponentModel;
namespace REWFComm
{
public delegate void MessageHandler(string myStr, object sender);
public interface ICommon
{
void Message(string passed, object sender);
event MessageHandler MessageEvent;
}
public class Messages : MarshalByRefObject
{
public void MessageArrived(string myStr, object sender)
{
From HERE I need to tell to client to modefy the control
}
}
}
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Hi,
what you need is a remoting callback. I am not familiar with it, but there are several articles
here on CP that deal with it, this is one of them.[^]. It all starts with a delegate, as usual...
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Thanks for link. but still I have blackout (((((
Any suggestions?
Thanks a lot
Ilan
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Ok here's what I'm trying to do:
using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Reflection;
using System.Runtime.Remoting;
using System.Drawing;
using System.Windows.Forms;
namespace GetConstructorTest
{
public class GooConsistency
{
public GooConsistency()
{
}
}
public class Monster
{
public Monster()
{
}
}
public class GooeyMonster: Monster
{
public GooeyMonster(GooConsistency gooness)
{
}
}
public class SqueltcheyMonster : Monster
{
public SqueltcheyMonster(Color tongueColor, bool isBackflipping)
{
}
}
public partial class Form1 : Form
{
public Form1()
{
object[] MonsterData1 = new object[] { new GooConsistency() };
Monster Monster1 = CreateMonster("GooeyMonster", MonsterData1);
}
public Monster CreateMonster(string type, Object[] vConstructorArgumentValues)
{
Type[] argtypes = Type.GetTypeArray(vConstructorArgumentValues);
Type t = Type.GetType(type);
ConstructorInfo info = t.GetConstructor(argtypes);
return info.Invoke(vConstructorArgumentValues) as Monster;
}
}
}
But on the line: ConstructorInfo info = t.GetConstructor(argtypes);
I get this exception:
System.NullReferenceException was unhandled
Message="Object reference not set to an instance of an object."
Source="GetConstructorTest"
StackTrace:
at GetConstructorTest.Form1.CreateMonster(String type, Object[] vConstructorArgumentValues) in G:\Portable Documents\Visual Studio 2008\Projects\GetConstructorTest\GetConstructorTest\Form1.cs:line 50
at GetConstructorTest.Form1..ctor() in G:\Portable Documents\Visual Studio 2008\Projects\GetConstructorTest\GetConstructorTest\Form1.cs:line 44
at GetConstructorTest.Program.Main() in G:\Portable Documents\Visual Studio 2008\Projects\GetConstructorTest\GetConstructorTest\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
Why?
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Probably Type.GetType(type) returned null, that's why t is null as well.
modified 12-Sep-18 21:01pm.
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Hi,
as the exception says, you have a null reference; there is only one reference on that line, so t is null.
reason seems to be you did not specify the full type name in the line above.
MSDN on Type.GetType() says "typeName can be the type name qualified by its namespace or an assembly-qualified name that includes an assembly name specification."
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Hi,
Can you please give me a practical example to distingish below two methods..
Method 1
string.Format("something","Something");
Method 2
string.Format(CultureInfo.CurrentCulture,"something","Something");
Thanks!
Charith Jayasundara
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Your first example simply calls your second example but with null as the first parameter. The second example exlicitly uses the current culture to render the formatting. In other words, if you ask it to format a number it will place the delimiters and decimal markers in the correct place and with the correct characters. For example, if your culuture is set to EN-GB then 1.234 will be rendered, whereas if your culture is NL-NL the same number would be rendered as 1,234
The .NET documentation has extesive examples of how to use Format and on formatting in general, that should be your starting point.
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Hi,
Thank you for the reply. I understand how it works for numbers. But what is the purpose of setting the culture for normal strings?
Charith Jayasundara
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Charith Jayasundara wrote: But what is the purpose of setting the culture for normal strings?
Because some people like consistency and will set all parameters explicitly all the time. Other than that, I don't think it makes any difference for strings.
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Great
Thank you!
Charith Jayasundara
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I have a table defined in a xsd that has an autoincrementing field that is used as the key to the table. The application uses ReadXML and WriteXML function to persists the dataset to an XML file. I am curious as to where the next value to use for the autoincrement field is persisted. I would have expected that when creating a new row in the table, the value for the ID field would be one greater than the highest value found in the table after the dataset is read in. It seems however to persist the highest value used in the past, even if those records have been deleted. In my application, when I create a new row, the ID field contains a 6071 when the highest value used before creating a new row was 5995. It does not appear that the autoincrement seed value is stored in the XML file itself, but where else would it be.
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Hello everyone,
I am writing a backend program which will upload some big files to another server and I want to detect whether current machine's network is busy or not (I want to use relative non-busy time of current machine to upload files, as I do not want to impact other network related task on the machine as the upload file task priority is low).
Does anyone have any idea about how to check whether current machine is busy with network I/O? Should I check some performance counters?
thanks in advance,
George
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