Re: how can I show the noobie the path instead of the knife? - C# Discussion Boards

Nagy Vilmos11-Mar-09 4:24

11-Mar-09 4:24

Dave Kreskowiak wrote:
Put down the flame thrower and step away slowly

Ain't gonna happen. Not while no bubba's callin me dude it ain't...
Laugh | :laugh:

Panic, Chaos, Destruction.
My work here is done.

#realJSOP11-Mar-09 3:19

#realJSOP

11-Mar-09 3:19

wwwxyz wrote:
I dont have any error message.

Then how do you know it's not working?

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

wwwxyz11-Mar-09 3:43

wwwxyz

11-Mar-09 3:43

I am not to be able to make oneself understood.

Original code is works that is first my sended the code.
But I want to convert it as secondly my sended the code then it isnt works

Nagy Vilmos11-Mar-09 4:23

11-Mar-09 4:23

JFC! I gave you the answer already; or at least told you how to advance.

1) Issolate the problem.
Find where it is going wrong and try to bebug it.

2) Your method input, which is crap, does not update the return value. Change the signature to:

private bool input(ref double fx,
        ref double ft,
        ref double alpha,
        ref int n,
        ref int m)

And call it somit like:

ok = input(ref fx,
        ref ft,
        ref alpha,
        ref n,
        ref m);

Don't change anything and compile. What do you see? Come on, you can do it! A few debug statements in the code and you'll soon see that the whole is method is a steaming puile of doo doo.

Personally, I would remove all the try/catch code and see what happens. then I would add try/catches where needed. This means you have to actually test your code for invalid input and/or data but it won't take long.

Panic, Chaos, Destruction.
My work here is done.

wwwxyz11-Mar-09 4:43

wwwxyz

11-Mar-09 4:43

firstly thanks for your helps

Error:'hard.Program.input(ref double, ref double, ref double, ref int, ref int)': not all code paths return a value

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.IO;

namespace hard
{
    class Program
    {
        static void Main(string[] args)
        {
            Program app = new Program();
        }

        Program()
        {
            bool ok = false;
            double[] w = new double[25];
            double[] l = new double[25];
            double[] u = new double[25];
            double[] z = new double[25];
            double ft = 0.0, fx = 0.0, alpha = 0.0, h = 0.0, k = 0.0, vv = 0.0, t = 0.0, x = 0.0;
            int n = 0, m = 0, m1 = 0, m2 = 0, n1 = 0, flag = 0, i1 = 0, i = 0, j = 0 ;
            
            ok=input(ref fx,ref ft,ref alpha,ref n,ref m);
            
            if (ok)
            {
                m1 = m - 1;
                m2 = m - 2;
                //    n1 = n - 1;
                /* step 1 */
                h = fx / m;
                k = ft / n;
                vv = alpha * k / (h * h);
                /* step 2 */
                for (i = 1; i <= m1; i++) w[i - 1] = F(i * h);
                /* step 3 */
                l[0] = 1.0 - 2.0 * vv;
                u[0] = vv / l[0];
                /* step 4 */
                for (i = 2; i <= m2; i++)
                {
                    l[i - 1] = 1.0 - 2.0 * vv - vv * u[i - 2];
                    u[i - 1] = vv / l[i - 1];
                }
                /* step 5 */
                l[m1 - 1] = 1.0 - 2.0 * vv - vv * u[m2 - 1];
                /* step 6 */
                for (j = 1; j <= n; j++)
                {
                    /* step 7 */
                    /* current t(j) */
                    //   t = j * k;
                    z[0] = w[0] / l[0];
                    /* step 8 */
                
                    for (i = 2; i <= m1; i++)
                        z[i - 1] = (w[i - 1] - vv * z[i - 2]) / l[i - 1];
                    /* step 9 */
                    w[m1 - 1] = z[m1 - 1];
                    /* step 10 */
                    for (i1 = 1; i1 <= m2; i1++)
                    {
                        i = m2 - i1 + 1;
                        w[i - 1] = z[i - 1] - u[i - 1] * w[i];
                    }
                }
                /* step 11 */
                output(ft, x, m1,ref w, h);
            }
            
        }

        
        private double F(double X)
        {
            double f;
            f = 0.3061 * X * X -2.1286*X+38.11;
            return f;
        }

        private bool input(ref double fx, ref double ft, ref double alpha, ref int n, ref int m )
        {
            try
            {
                FileStream fs = new FileStream("d:\\a.txt", FileMode.Open);
                StreamReader sr = new StreamReader(fs);

                List<string> lines = new List<string>();
                String line;
                //add all the lines to a list
                while ((line = sr.ReadLine()) != null)
                {
                    lines.Add(line);
                }
                //read the lines you would like to read:
                try
                {
                     fx = double.Parse(lines[0]);
                     ft = double.Parse(lines[1]);
                 alpha = double.Parse(lines[2]);
                     m = Int32.Parse(lines[3]);
                     n = Int32.Parse(lines[4]);
                }
                catch { }
            }
            catch (Exception e)
            {
                Console.WriteLine("Exception in ShowFile: {0}", e);
            } 
            
        }

        public void output(double ft, double x, int m1, ref double[] w, double h)
        {
            System.IO.StreamWriter oup;
            System.IO.TextWriter tmp = Console.Out;
            Console.WriteLine("Choice of output method.");
            Console.WriteLine("1. Output to screen");
            Console.WriteLine("2. Output to text file");
            int flag = Convert.ToInt32(Console.ReadLine());
            if (flag == 2)
            {
                
                Console.WriteLine("Sample:   D:\\1.txt");
                string name = Console.ReadLine();
                try
                {
                    
                    oup = new System.IO.StreamWriter(name);
                    Console.SetOut(oup);
                    write(ft, x, m1, ref w, h);
                    oup.Close();
                }
                catch (System.IO.IOException expc)
                {
                    Console.WriteLine(expc.Message + " file dont extract.");
                }
            }
            else
            {
                write(ft, x, m1, ref w, h);
            }


        }

        private void write(double ft, double x, int m1, ref double[] w, double h)
        {
            
            Console.WriteLine("I\tX(I)\tW(X(I),{0:#.#})", ft);
               for (int i = 1; i <= m1; i++)
            {
                x = i * h;
                Console.WriteLine("{0:#.##}\t{1:#.###}\t\t{2:#.###}", i, x, w[i - 1]);
            }
        }
    }
}

   </string></string>

Nagy Vilmos11-Mar-09 4:46

11-Mar-09 4:46

Correct, now WHY?
The return value is not being set. You were supposed to work that one out.

Panic, Chaos, Destruction.
My work here is done.

Re: how can I show the noobie the path instead of the knife?

#realJSOP11-Mar-09 4:50

#realJSOP

11-Mar-09 4:50

Dude, yer spittin' into the wind. All that's gonna happen is you'll end up with spit all over yourself. Nothing else will change.

We are CodeProject of Borg. Assistance is futile.

Nagy Vilmos11-Mar-09 5:12

11-Mar-09 5:12

I know. I like to help, I really do. The problem is, well you know EXACTLY what the problem is.

So I've resolved to trying to prod them in the right direction. Using an electrified cattle stick. As the average intelligence comes out around duckweed, one has to derive what little pleasure is available.

In other news, it is now afternoon here and the Gin should be kickiing in around about now.

Panic, Chaos, Destruction.
My work here is done.

fly90411-Mar-09 11:29

fly904

11-Mar-09 11:29

Dumbest mistake I've seen all day.

What happens when you use a function which is not a void?

The function has to return something eg:

private bool rawr()
{
    bool returnObject = false;

    ...

    return returnObject;
}

It's not rocket science it just common sense!

hmmm pie

modified on Saturday, March 14, 2009 6:56 AM

wwwxyz11-Mar-09 5:13

wwwxyz

11-Mar-09 5:13

Thanks everyone!

finally code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Program app = new Program();
            Console.ReadLine();
        }

        Program()
        {
            bool ok = false;
            double[] w = new double[25];
            double[] l = new double[25];
            double[] u = new double[25];
            double[] z = new double[25];
            double ft = 0.0, fx = 0.0, alpha = 0.0, h = 0.0, k = 0.0, vv = 0.0, t = 0.0, x = 0.0;
            int n = 0, m = 0, m1 = 0, m2 = 0, n1 = 0, flag = 0, i1 = 0, i = 0, j = 0;
            input(ref ok, ref fx, ref ft, ref alpha, ref n, ref m);

            if (ok)
            {
                m1 = m - 1;
                m2 = m - 2;
                //    n1 = n - 1;
                /* step 1 */
                h = fx / m;
                k = ft / n;
                vv = alpha * k / (h * h);
                /* step 2 */
                for (i = 1; i <= m1; i++) w[i - 1] = F(i * h);
                /* step 3 */
                l[0] = 1.0 - 2.0 * vv;
                u[0] = vv / l[0];
                /* step 4 */
                for (i = 2; i <= m2; i++)
                {
                    l[i - 1] = 1.0 - 2.0 * vv - vv * u[i - 2];
                    u[i - 1] = vv / l[i - 1];
                }
                /* step 5 */
                l[m1 - 1] = 1.0 - 2.0 * vv - vv * u[m2 - 1];
                /* step 6 */
                for (j = 1; j <= n; j++)
                {
                    /* step 7 */
                    /* current t(j) */
                    //   t = j * k;
                    z[0] = w[0] / l[0];
                    /* step 8 */

                    for (i = 2; i <= m1; i++)
                        z[i - 1] = (w[i - 1] - vv * z[i - 2]) / l[i - 1];
                    /* step 9 */
                    w[m1 - 1] = z[m1 - 1];
                    /* step 10 */
                    for (i1 = 1; i1 <= m2; i1++)
                    {
                        i = m2 - i1 + 1;
                        w[i - 1] = z[i - 1] - u[i - 1] * w[i];
                    }
                }
                /* step 11 */
                output(ft, x, m1, ref w, h);
            }

        }


        private double F(double X)
        {
            double f;
            f = 0.3061 * X * X - 2.1286 * X + 38.11;
            return f;
        }

        private void input(ref bool ok, ref double fx, ref double ft, ref double alpha, ref int n, ref int m)
        {
            try
            {
                FileStream fs = new FileStream("D:\\1.txt", FileMode.Open);
                StreamReader sr = new StreamReader(fs);

                string[] lines = new string[10]; // you cannot use list like that
                string line;
                //add all the lines to a list
                int i = 0;
                while ((line = sr.ReadLine()) != null)
                {
                    lines[i++] = (line);
                }
                //read the lines you would like to read:
                
                    fx = double.Parse(lines[0]);
                    ft = double.Parse(lines[1]);
                    alpha = double.Parse(lines[2]);
                    m = Int32.Parse(lines[3]);
                    n = Int32.Parse(lines[4]);
              
            }
            catch (Exception e)
            {
                Console.WriteLine("Exception in ShowFile: {0}", e);
            }
            ok = true;
        }

        public void output(double ft, double x, int m1, ref double[] w, double h)
        {
            System.IO.StreamWriter oup;
            System.IO.TextWriter tmp = Console.Out;
            Console.WriteLine("Choice of output method.");
            Console.WriteLine("1. Output to screen");
            Console.WriteLine("2. Output to text file");
            int flag = Convert.ToInt32(Console.ReadLine());
            if (flag == 2)
            {

                Console.WriteLine("Sample:   C:\\Data\\1.txt");
                string name = Console.ReadLine();
                try
                {
                    name = name.Replace(@"\", @"\\"); // look at the changes in the path
                    oup = new System.IO.StreamWriter(name);
                    Console.SetOut(oup);
                    write(ft, x, m1, ref w, h);
                    oup.Close();
                }
                catch (System.IO.IOException expc)
                {
                    Console.WriteLine(expc.Message + " file dont extract.");
                }
            }
            else
            {
                write(ft, x, m1, ref w, h);
            }


        }

        private void write(double ft, double x, int m1, ref double[] w, double h)
        {

            Console.WriteLine("I\tX(I)\tW(X(I),{0:#.#})", ft);
            for (int i = 1; i <= m1; i++)
            {
                x = i * h;
                Console.WriteLine("{0:#.##}\t{1:#.###}\t\t{2:#.###}", i, x, w[i - 1]);
            }
        }
    }
}

#realJSOP11-Mar-09 5:28

#realJSOP

11-Mar-09 5:28

You really don't need to post the code every frakking time you put up a message.

Nagy Vilmos11-Mar-09 5:30

Re: check if in safe mode

11-Mar-09 5:30

Calm down, Chris has just ordered a couple of extra 250 TB dirve racks for when the next term starts. Laugh | :laugh:

And now sport, Gin 3 Tonic 2. Gin goes onto to meet Liver in the next round. Unsure | :~

Panic, Chaos, Destruction.
My work here is done.

check if in safe mode

aviadqwerty11-Mar-09 1:26

aviadqwerty

11-Mar-09 1:26

Hi,
I'm trying to write a service that runs only in safe mode,
for that i need to figure out if I'm in safe mode or not,
how do i do that in c# ? (i cant use System.Windows.Forms.SystemInformation.BootMode since i'm in a service and no forms)

Thanks
Aviad.

Luc Pattyn11-Mar-09 1:44

Luc Pattyn

11-Mar-09 1:44

aviadqwerty wrote:
i cant use System.Windows.Forms.SystemInformation.BootMode since i'm in a service

I doubt that. Why would it be impossible to add a reference to ths System.Windows.Forms DLL and use the SystemInformation.BootMode enum? you don't need a GUI to do that. Have you tried it, what happened?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
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Change desktop wallpaper via windows service (vista)

maxald11-Mar-09 0:57

Wrong Place For This Question

11-Mar-09 0:57

Hello! I am following this guide about switching background wallpaper via a windows service http://www.codeproject.com/KB/cs/C__Wallpaper_Switcher.aspx[^] but cant get it right.

My service is up and running (it do other things så of that I am certain) but the background wont just change. If I try exactly the same code in a win form app it works (and SystemParametersInfo returns 1) but not in my service (SystemParametersInfo returns 0). Has Vista something to do with it, security limitations? Is it posible to get better error messages from SystemParametersInfo?

Nagy Vilmos11-Mar-09 1:16

11-Mar-09 1:16

Don't ask here, it's not our code. Any qiestion regarding an article should be posted on the article. It's really quite a clever idea - you ask the person who wrote it why you're having a problem.

Panic, Chaos, Destruction.
My work here is done.

maxald11-Mar-09 3:10

11-Mar-09 3:10

Well then maybe I can change my question a bit? Regardless of the article, how do I change the background image within a windows service? I have search the web for hours now and all code are variations of the code as shown in the article (pretty much c# to me and this is a c# forum, right?)...

[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern Int32 SystemParametersInfo(UInt32 uiAction, UInt32 uiParam, String pvParam, UInt32 fWinIni);
private static UInt32 SPI_SETDESKWALLPAPER = 20;
private static UInt32 SPIF_UPDATEINIFILE = 0x1;

/.../

SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, @"C:\...\test.bmp", SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE);

Works perfectly in win forms in vista but not in my service of some reason.

Nagy Vilmos11-Mar-09 3:21

11-Mar-09 3:21

It's a service. You shouldn't be able to access the UI from a service.

Panic, Chaos, Destruction.
My work here is done.

Dave Kreskowiak11-Mar-09 4:22

Dave Kreskowiak

11-Mar-09 4:22

It won't work in a service because the service is running under a different account and Desktop. You're actually changing the wallpaper for a desktop that you cannot see.

This should not be done from a service at all. This should be a user app launched from the Run key in the registry. Wallpaper setting a user specific, not machine specific. This means that every user can have their own wallpaper, without affecting other users.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

maxald12-Mar-09 4:32

12-Mar-09 4:32

Ok, thanks. I did find a "half workaround". It is possible to change the wallpaper registry key with the standard service account. Smile | :)

Not directly in HKEY_CURRENT_USER but in HKEY_USER. And hkey_current_user is in fact only a copy of one of thoose in the hkey_users, just find the right one (the one with write permissions is the same as hkey_current_user so just loop them through an try them out...)

Changing the wallpaper key only applies when the computer is restarted, but it was quite fun anyway. Smile | :)

The image has to be find locally but if removed, I made my service download the correct image aswell...

RegistryKey Keys = Registry.Users;
//using a foreach loop to display each subkeyname
foreach (string Keyname in Keys.GetSubKeyNames())
{
    try
    {
        RegistryKey  Key = Registry.Users.OpenSubKey(Keyname.ToString() + "\\Control Panel\\Desktop", true);
        Key.SetValue("WallPaper", "C:\\Users\\" + UsersDir + "\\Desktop\\funny.jpg", RegistryValueKind.String);
    }
    catch { }
}

Not very serious project maybe but I've learned alot on the way.

Dave Kreskowiak12-Mar-09 12:20

Dave Kreskowiak

12-Mar-09 12:20

CURRENT_USER is a pointer to the correct user hive under USERS, not a copy of it.

maxald wrote:
just find the right one (the one with write permissions is the same as hkey_current_user so just loop them through an try them out...)

This is wrong. Services run, by default, as the Local System account, not a user account. They also don't normally have any idea anyone is logged in, if at all. The fact that the service found A user have that it could write to is mearly a coinicedence. It did not find THE known user account, unless you've written code to try and figure out which user that is.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

maxald12-Mar-09 21:05

12-Mar-09 21:05

Thanks for clearing things out, I'm all new to programming so I really appreciate that! Smile | :)

I find one other thing on this subject... when looping trough all user folders in c:\Users within my service, it has write permissions only in the logged in user folder. Is this a coinicedence aswell or could this be part of a solution finding who is the logged in user?