C# Discussion Boards - CodeProject

How to sort ListView items of some column.

27-Mar-07 9:08

I think what you want to use is xpath.

Re: C# XmlReader

BoneSoft27-Mar-07 9:44

BoneSoft

27-Mar-07 9:44

If you're just trying to extract data from XML, you don't even need the schema. If you know the elements, you could just load the XML into an XmlDocument object and XPath query out what you need.

Try code model generation tools at BoneSoft.com.

Saikek27-Mar-07 8:11

Saikek

27-Mar-07 8:11

Hello, my cybrenetics Friends !!!

I have a listview, and o wan't to sort the list by clicking the Column header.
But i have 2 columns, and i wan't to sort the list by clicking the 2 column, so i can get the items sorted by the second raw.

Thanks!!!

One nation - underground

Re: How to sort ListView items of some column.

BoneSoft27-Mar-07 9:52

BoneSoft

27-Mar-07 9:52

There are several ways you could do this. But you'll likely want to create an IComparer implementation to look at ListViewItems, or whatever type you stick in the ListViewItem's Tag property. When you add an event handler for the ListView's ColumnClick event, the ColumnClickEventArgs instance gives you the index of the column clicked. You can use that in your IComparer to determine how to sort objects. In your handler, update or create a new comparer and set the ListView's ListViewItemSorter property with the instance you updated or created. Google IComparer to see how to implement one, but it's not difficult.

private void listView1_ColumnClick(object sender, ColumnClickEventArgs e) {
    IComparer sorter = new YOURICOMPARER(e.Column)
    listView1.ListViewItemSorter = sorter;
    listView1.Sort();
}

Try code model generation tools at BoneSoft.com.

Re: How to sort ListView items of some column.

rahvyn627-Mar-07 9:54

rahvyn6

27-Mar-07 9:54

Check this article out, I think its what you're looking for: http://support.microsoft.com/kb/319401[^]

Source ThreadException

AAKAra27-Mar-07 8:06

AAKAra

27-Mar-07 8:06

Hello,
when i install my application, i get a fatal error message " Fatal Non-UI Error. Could not write the error to the event log. Reason: Source ThreadException already exists on the local computer."
I dont get this message on al machine, i get this error only on couple of our sites..
this is my main

static void Main() <br />
		{<br />
            Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException);<br />
            Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);<br />
<br />
            // Add the event handler for handling non-UI thread exceptions to the event. <br />
            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);<br />
<br />
			CSingleProcInstance singleProcInstance = new CSingleProcInstance();<br />
			if(singleProcInstance.IsSingleInstance())<br />
				Application.Run(new MainForm());<br />
<br />
			// let it go<br />
			singleProcInstance.Release();<br />
        }<br />

the exception is in the AppDomain.CurrentDomain part of the code.,

private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)<br />
        {<br />
            try<br />
            {<br />
                Exception ex = (Exception)e.ExceptionObject;<br />
                string errorMsg = "An application error occurred. Please contact the adminstrator " +<br />
                    "with the following information:\n\n";<br />
<br />
                // Since we can't prevent the app from terminating, log this to the event log.<br />
                if (!EventLog.SourceExists("ThreadException"))<br />
                {<br />
                    EventLog.CreateEventSource("ThreadException", "Application");<br />
                }<br />
<br />
                // Create an EventLog instance and assign its source.<br />
                EventLog myLog = new EventLog();<br />
                myLog.Source = "ThreadException";<br />
                myLog.WriteEntry(errorMsg + ex.Message + "\n\nStack Trace:\n" + ex.StackTrace);<br />
            }<br />
            catch (Exception exc)<br />
            {<br />
                try<br />
                {<br />
                    MessageBox.Show("Fatal Non-UI Error",<br />
                        "Fatal Non-UI Error. Could not write the error to the event log. Reason: "<br />
                        + exc.Message, MessageBoxButtons.OK, MessageBoxIcon.Stop);<br />
                }<br />
                finally<br />
                {<br />
                    Application.Exit();<br />
                }<br />
            }<br />
	}

Can someone suggest me how to go about this Error?
With Rgds,
Anil

2 Questions

JMOdom27-Mar-07 7:35

JMOdom

27-Mar-07 7:35

I trying to learn C# and I've got two questions for someone. Confused | :confused:

1) In my property statements when I have a speed property I keep getting told The type 'CarProjects.Car' already contains a definition for 'Speed'. I didn't think that I really had a definition for Speed in there. Hopefully someone can explain what I may be doing wrong. Confused | :confused:

2) In the Decelerate() method I need to take the final speed from accelerate and use it to set up for my braking speed. The way it is now I'm fine with the accelerate which gives me a 25 MPH boost over the initial speed. I can also get a -25 MPH shown in the decelerate. I had originally thought that I could make a method that would add the "brake" speed to the "speed" method. I simpply can't get it to work. Can someone give me a clue as to how I can make this work? Sigh | :sigh:

Any help will be appreciated. Smile | :)

public class Car     <br />
	   private int speed = 0;<br />
        private int brake = 0;<br />
		 private int Accel = 0;<br />
        private int Speed = 0;<br />
		//Property statment<br />
		<br />
        public int Speed<br />
        {<br />
            get<br />
            {<br />
                return speed;<br />
            }<br />
            set<br />
            {<br />
                speed = value;<br />
            }<br />
        }<br />
		public int Brake<br />
        {<br />
            get<br />
            {<br />
                return brake;<br />
            }<br />
            set<br />
            {<br />
                brake = value;<br />
            }<br />
        }<br />
		<br />
		 public Car(int speed, int brake, int accelerate)<br />
        {<br />
            accelerate = Accel;<br />
            brake = Brake;<br />
            speed = Speed;<br />
        }<br />
		<br />
		public static int Accelerate() <br />
        {<br />
            int speed = 0;<br />
            int counter = 1;<br />
            Console.WriteLine();<br />
            Console.WriteLine("Type in the initial speed of car.");<br />
            string inputNumbers = Console.ReadLine();<br />
            speed = int.Parse(inputNumbers);<br />
            <br />
            while (counter < 6)<br />
            {<br />
                speed += 5;<br />
                counter++;<br />
              }<br />
              Console.WriteLine();<br />
              Console.WriteLine("Top speed of the car is: {0}", speed);<br />
              return speed;<br />
          }<br />
	}<br />
            public static int Decelerate()<br />
          {<br />
            int brake = 0;<br />
            int counter = 1;<br />
            while (counter < 6)<br />
            {<br />
				brake += - 5;<br />
                counter++;<br />
            }<br />
            Console.WriteLine();<br />
            Console.WriteLine("Speed after braking is: {0} ", brake);<br />
            return brake;<br />
	}<br />
        }

led mike27-Mar-07 7:48

led mike

27-Mar-07 7:48

JMOdom wrote:
private int Speed = 0;

JMOdom wrote:
public int Speed
{
get
{
return speed;
}
set
{
speed = value;
}
}

led mike

Leslie Sanford27-Mar-07 7:55

Leslie Sanford

27-Mar-07 7:55

JMOdom wrote:
1) In my property statements when I have a speed property I keep getting told The type 'CarProjects.Car' already contains a definition for 'Speed'. I didn't think that I really had a definition for Speed in there. Hopefully someone can explain what I may be doing wrong.

I run into this problem when I accidently give a field (or method) the same name as a property. For example, if you have a field named "Speed" and a property named "Speed," you'll get the above error.

JMOdom wrote:
2) In the Decelerate() method I need to take the final speed from accelerate and use it to set up for my braking speed. The way it is now I'm fine with the accelerate which gives me a 25 MPH boost over the initial speed. I can also get a -25 MPH shown in the decelerate. I had originally thought that I could make a method that would add the "brake" speed to the "speed" method. I simpply can't get it to work. Can someone give me a clue as to how I can make this work?

I think I need a clearer statement of what your goal is with the brake method. You're simulating a car, right? You have an Accelerate and Decelerate methods for increasing a car's speed and decreasing a cars speed respectively. Maybe a restatement of what you're having problems with would help. I'm a little lost.

JMOdom27-Mar-07 11:02

JMOdom

27-Mar-07 11:02

I'll try and clear things up. Laugh | :laugh:

With this project that I'm working on I should be able to input an initial speed. The program will then take and add 5 MPH to it 5 times.

When I get that final speed from the acceleration I then take it and use it in the decelerate method. It does the same thing with the following exception:
Instead of adding 5 MPH to the speed it subtracts 5 MPH 5 times. I need to get back my original speed that I typed in.

Hopefully that helps clear things up. Big Grin | :-D

Leslie Sanford27-Mar-07 11:14

Leslie Sanford

27-Mar-07 11:14

Ok, the main thing is that you need to maintain the state of the car during and between calls to Accelerate and Decelerate. In other words, you need to keep track of the speed of the car during and between calls to those methods. You can do this with a speed field. This is a trivial example, but it should show you in principle what I'm talking about:

using System;
 
namespace Demo
{
    public class Counter
    {
        private int count;
 
        public Counter(int initialCount)
        {
            count = initialCount;
        }
 
        public void Increment()
        {
            count++;
        }
 
        public void Decrement()
        {
            count--;
        }
 
        public int Count
        {
            get
            {
                return count;
            }
        }
    }
}

To use this object, we could do this:

Counter c = new Counter(40);
 
c.Increment();
c.Increment();
c.Decrement();
 
// etc...

Now, hopefully this will get you started. In place of the Increment method, you will use the Accelerate method. And instead of the Decrement method, you will use the Decelerate method. And instead of the Count property, you will use the Speed property, and so on. You will then need to put in extra logic to handle your requirements regarding maximum speed allowed and so forth.

The key here is that encapsulated in the Counter object is the state of the object. This state is maintained between calls to the methods. I'm not sure, but I think this may have been where you were having trouble with your code. I'd need to take a second look.

Rudolf Jan28-Mar-07 0:10

Rudolf Jan

28-Mar-07 0:10

On the fifth line you declare Seed two lines later you declare the property Speed with the same name. It is a dangerous habit to use speed and Speed in the same module. For properties I normally create a private var like this PropSpeed, then the property itself has the more friendly name Speed.

I think your model is nog good. If you intend to use Speed as the actual seepd an you simulate braking, just decrease the speed again, till it treaches 0. You do not need the brake proerty for this purpose. It might make sens to introcuce properties for accelleration to set the accelleration capability and use this to calculate the new speed:
speed += accelleration;

In the same way you may want to use a different value for brakng capacitiy, e.g. brake:

speed -= brake;

I hope this helps.

System.Diagnostics.Process.StartInfo Username= "default user"?

JMOdom28-Mar-07 13:27

JMOdom

28-Mar-07 13:27

Thanks folks. I'll be trying the various solutions to see which gives me the best results.

Blush | :O

As I'm new at this, and in a learning mode, sometimes I find that you learn more from how not to do something than from how to do it. D'Oh! | :doh:

Thanks again for your time and efforts. They are all appreciated. Cool | :cool:

Austin Harris27-Mar-07 6:59

Re: System.Diagnostics.Process.StartInfo Username= "default user"?

27-Mar-07 6:59

Hello,

Problem is that I am trying to launch a windows forms application process from the context of a windows service, via a intermediate update process.

The service launches the update process just fine. The update process determines if it needs to shutdown the service and apply an update to it. It then restarts the service. This update process is currently launching under the context of the service. IE: Its parent process is the service process, and is owned / its User is "NT Authority\System".

Everything is fine to this point. After the service is updated and restarted I then have to open a windows form application (the service's controlling interface) "IF" there is a user logged into the system, and it must run under that users account (I believe).

I launch the interface process like so:

<br />
 // launch the UI<br />
Process process = new Process();<br />
process.StartInfo.UseShellExecute = true;<br />
process.StartInfo.RedirectStandardOutput = false;<br />
process.StartInfo.RedirectStandardError = false;<br />
process.StartInfo.FileName = Application.StartupPath + "\\serviceInterface.exe";<br />
process.StartInfo.Arguments = " -updated";<br />
process.StartInfo.LoadUserProfile = true;<br />
process.StartInfo.WorkingDirectory = Application.StartupPath;<br />
process.StartInfo.CreateNoWindow = false;<br />
process.StartInfo.WindowStyle = ProcessWindowStyle.Normal;<br />
process.Start();<br />

The process starts and is diplayed under processes in taskmanager. It does not get a window handle though it seems.
Whatever I try I cannot bring the process to focus. If I try to bring the processes main window to front I get an error that there is no window associated with the process.

I have determined that the problem roots from the user account that the process is launched under, as when I lauch the update process manually under the default users account every thing works fine.

Hard coding a username and password is not an option as I would then have to create that account on each machine the service is installed on.

How can I get my process to start under the context of the local users account, if there is one logged in? Also what if there are mutlipule terminal sessions open to the server, how do I pick the approperate one to launch under?

Thanks a ton for any info.

Been stumped here for a little bit.

kubben27-Mar-07 7:57

kubben

27-Mar-07 7:57

You must not be using .net 2.0. There is a UserName and Password property in the StartInfo object of the Process in .net 2.0. Otherwise you are kind of stuck since what ever the service launches will be run under the user that the windows service is installed as.

The only other thing I can think of is not very clean. You could have the windows service send a windows message to your app. When that app receives that windows message, it could launch a small exe who's only purpose is to poll a directory or register setting that will get set when the update is done. One this little app see the update is done it launches the app again. Since it was started by the orignal application it should work fine.

Or you could just upgrade your service to .net 2.0.

Hope that helps.
Ben

Re: System.Diagnostics.Process.StartInfo Username= "default user"?

Austin Harris27-Mar-07 8:48

Re: System.Diagnostics.Process.StartInfo Username= "default user"?

27-Mar-07 8:48

I am using .net 2.0
I do see the startinfo.Username
and startinfo.Password

I suppose Knowing how to get the password for the default active user would do the trick as well.

kubben27-Mar-07 9:19

kubben

27-Mar-07 9:19

I haven't tried it, but it might just work to set the UserName and the domain properties if the user is logged in.

This would get you the logged in user:
WindowsPrincipal wp = new WindowsPrincipal(WindowsIdentity.GetCurrent());
String username = wp.Identity.Name;

I believe this will include the domain.

Hope that helps.
Ben

Auto generated number

Neo_Shehpar27-Mar-07 6:44

Neo_Shehpar

27-Mar-07 6:44

Dear All,
i have problem in producing the auto generated number. my requirements are to produce series of numbers like that
AAA-0000
AAA-0001
up
.
.
.
AAA-9999

after that the number changes to

AAB-0000
AAB-0001
.
.
.
.
AAB-9999

the last number should be
ZZZ-9999

If there is any person who help me in producing that module / algorithm or piece of code in C# / T-SQL, i will be thankful for that.

NOTE:- the number should me auto generated i.e., after one transaction the new number would be generated.
or. in case of T-SQL, when inserting new record, the eky would be that number like the example that i stated above.

Hope that there is someone which will help me.

Best regards.

Leslie Sanford27-Mar-07 7:23

Leslie Sanford

27-Mar-07 7:23

I don't know if I can offer help here as I'm not familiar with "T-SQL." Do you just need an algorithm for generating the numbers?

Off the top of my head, one way to do it would be to have an integer representing the first part of the number, the 0000 part. Also have three characters, each representing one of the letters in the letter part of the number. Initialize the number to 0 and each character to 'A', and do something like this:

using System;
using System.Collections.Generic;
using System.Text;
 
namespace AutoNumber
{
    class Program
    {
        static int number = 0;
        static char[] characters = { 'A', 'A', 'A' };
 
        static void Main(string[] args)
        {
            for(int i = 0; i < 10000; i++)
            {
                Console.WriteLine(GenerateNumber());
            }
 
            Console.Read();
        }
 
        static string GenerateNumber()
        {
            number++;
 
            if(number > 9999)
            {
                number = 0;
 
                for(int i = characters.Length - 1; i >= 0; i--)
                {
                    if(characters[i] == 'Z')
                    {
                        characters[i] = 'A';
                    }
                    else
                    {
                        characters[i]++;
 
                        break;
                    }
                }
            }
 
            return new string(characters) + "-" + number.ToString();
        }
    }
}

The algorithm rolls over after you reach ZZZ-9999.

Christian Graus27-Mar-07 7:26

Christian Graus

27-Mar-07 7:26

You need to use a format string so that he gets 0000 and not 0. Otherwise, this looks pretty good to me. I was just too lazy to do it for him Smile | :)

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Christian Graus27-Mar-07 7:24

Christian Graus

27-Mar-07 7:24

Generating it in C# should be easy enough. Remember that a char implictly converts to int. So, you can store three chars, and a number, and increment from there.

Austin Harris27-Mar-07 7:27

27-Mar-07 7:27

Something like this do the trick?

<code>
public static string nextNumber(string num)
{
if (num == "")
num = "AAA-0000";
string[] parts = num.Split(new char[] { '-' }, System.StringSplitOptions.RemoveEmptyEntries);
if(parts.Length == 2) // else incorect format
{
string charPart = parts[0];
string intPart = parts[1];
int part = 0;
int.TryParse(intPart, out part);
if (part < 9999)
{
part++;
}
else
{
part = 0;
// we must now increment the char part.
bool incrementedChar = false;
int position = charPart.Length - 1;
while (!incrementedChar)
{
if (charPart[position] >= 'Z')
{
// set last char to A,
char[] chars = charPart.ToCharArray();// = charPart[position]+1;
chars[position] = 'A';
charPart = chars.ToString();
if (position > 0)
{--position;}
else
{
// we are at 'ZZZZ'
}
// and the next position to char++ (do this in the next iteration).
}
else
{
// we increment the char at this position
char[] chars = charPart.ToCharArray();// = charPart[position]+1;
++chars[position];
charPart = chars.ToString();
incrementedChar = true;
}
}

num = charPart + part.ToString("-0000");
}
}
return num;
}
</code>

kubben27-Mar-07 7:42

kubben

27-Mar-07 7:42

This seems to work. Just pass in the current max key.

private string NextKey(string currentKey)
{
string ret = string.Empty;
string[] parts = currentKey.Split('-');
if (parts.Length == 2)
{
string alpha = parts[0];
Int32 numeric = Convert.ToInt32(parts[1]);
numeric++;
if (numeric > 999)
{
numeric = 0;
alpha = UpdateAlpha(alpha);
}
ret = alpha + "-" + Convert.ToString(numeric).PadLeft(3, '0');
}
return ret;
}

private string UpdateAlpha(string alpha)
{
string ret = string.Empty;
Char c = ' ';

for (Int32 i = alpha.Length-1; i >= 0;i-- )
{
c = alpha[i];
if (c == 'Z' && i != 0)
{

ret += 'A';
}
else if ((Int32)c < (Int32)'Z')
{
if (i == alpha.Length - 1)
{
ret += Convert.ToChar((Int32)c + 1);
}
else
{
ret = Convert.ToChar((Int32)c + 1) + ret;
}
for (Int32 j = i - 1; j >= 0; j--)
{
ret = alpha[j] + ret;
}
break;
}
else
{
ret += c;
}
} //foreach
return ret;
}

I tested it with this:
string key = "AAA-999";
richTextBox1.AppendText(key + Environment.NewLine);
// Int32 cnt = 0;
while (key != "ZZZ-999")// && cnt < 30001)
{
key = NextKey(key);
richTextBox1.AppendText(key+Environment.NewLine);
// cnt++;
} //while

Hope that helps.
Ben

Austin Harris27-Mar-07 8:52