[chenaz]

Hi,

i created a button which will create a log file which contain a running number and other info.
the number will increase after each click. this works fine if the application is running and the number log.writeline(i) will increase the number by 1-2-3-4-5...

how do i make the application to detect the last number of the i and continue the number after i re run the application.

current problem is. everytime i restart the application, the loop will start from one again which is not wat i want. i wan it to continue from last number that i had closed.

 
Int32 i;

        #region Functions
        private void button2_Click(object sender, EventArgs e)
        {
   string titletext = "History log ";
           
            i = ++i;

            // Create a writer and open the file:

            StreamWriter log;
    
            if (!File.Exists("running.log"))
            {
                log = new StreamWriter("running.log");
                log.WriteLine(i);

            }
            else
            {
                log = File.AppendText("running.log");

                log.WriteLine(i);

            }




            // Write to the file:
            log.WriteLine(titletext + " of " + DateTime.Now);
            log.WriteLine("User:" + textBox2.Text);
            log.WriteLine("From" + dateTimePicker1);
            log.WriteLine("To" + dateTimePicker2);
 
            // Close the stream:
            log.Close();

[Momerath]

You'll have to read the log file and find the last number used.

[chenaz]

Momerath, on 09 October 2012 - 09:00 PM, said:

You'll have to read the log file and find the last number used.

so after reading the file. wat should i do?

[tlhIn`toq]

Read the file line by line.
Get the value
When you get to the end, you know the last number used.
Continue as you previously described was working for you.

Don't over think it.

[chenaz]

tlhIn`toq, on 09 October 2012 - 09:31 PM, said:

Read the file line by line.
Get the value
When you get to the end, you know the last number used.
Continue as you previously described was working for you.

Don't over think it.

first thanks all. under

log.WriteLine("i: {0}", data["i"]);

as my running number was "i"
the system show an error saying cant find the keyword in the dictionary

so this is my new code.

 if (!File.Exists("running.log"))
            {
                log = new StreamWriter("running.log");
                log.WriteLine(i);
            }
            else 
            {
               
                var data = File
                      .ReadAllLines("running.log")
                      .Select(x => x.Split('='))
                      .Where(x => x.Length > 1)
                      .ToDictionary(x => x[0].Trim(), x => x[1]);
                log = File.AppendText("running.log");
                log.WriteLine("i: {0}", data["i"]);
                
                
            }

[tlhIn`toq]

try this as a test.


log.WriteLine(string.format("i: {0}", data["i"]));

[tlhIn`toq]

Oh crap...

var data = File
                     .ReadAllLines("running.log")
                     .Select(x => x.Split('='))
                     .Where(x => x.Length > 1)
                     .ToDictionary(x => x[0].Trim(), x => x[1]);
               log = File.AppendText("running.log");
               log.WriteLine("i: {0}", data["i"]);              
           }

It looks like you are reading the entire file to get the next line number - EVERY TIME YOU WRITE TO THE FILE.

Are you kidding? So if you write 100 entries you read the entire file 99 times? Wait until your log is a few thousand lines long and you see how badly this slows down your application. It will get to the point were it takes longer to read/write than for your program to operate: IE, 3 log entires a second, but each entry takes 5 seconds to create... so the program lags more and more with every entry.

You might want to re-think your logic. Why would you have to read the entire file EVERY TIME you write? Just do it one time to get the line number you need WHEN YOU LAUNCH THE APPLICATION, and store that.

This is a great example of what we say over and over and over....
Plan, plan some more, plan again, then rethink... Then plan some more...
All before you ever type a single character.

You have to decide if you want to be a "software engineer" or a code monkey. There's work out there for both. But if you want to be an actual software engineer then you need to take the time to do the engineering part of the software. Otherwise, there's always (lower paying) work for code monkey's that just do the grunt work that someone else engineered, defined and laid out.

[chenaz]

Yes i noe this problem will happen.

so advise me on the code as i am not a very good in coding.
and ur code does not work also.

giving error(The given key was not present in the dictionary.)

my result is somethng like this.

1
History log of 11/10/2012 10:08:12 AM
User:
FromSystem.Windows.Forms.DateTimePicker, Value: 11/10/2012 10:08:10 AM
ToSystem.Windows.Forms.DateTimePicker, Value: 11/10/2012 10:08:10 AM

after i restart the program. i wan it to continue the number 1and continue with 2.
since it is first character. wat should i use for the split?

[Curtis Rutland]

Quote

and ur code does not work also.

You do realize that was your code that he copied to highlight a point? If you don't recognize your own code, that makes me believe that you didn't write it in the first place, you found it and copied it.

Quote

so advise me on the code as i am not a very good in coding.

I'm tired of people telling me how bad at coding they are. If you're bad, get better or quit. Don't get other people to do your work for you.

[tlhIn`toq]

chenaz, on 10 October 2012 - 08:04 PM, said:

so advise me on the code as i am not a very good in coding.

I already gave you advice on this.

Quote

Just do it one time to get the line number you need WHEN YOU LAUNCH THE APPLICATION, and store that.

You won't get better if you don't make efforts. Trial and error. You might consider learning more from books and tutorials and STOP trying to architect new programs until you know more. You can't start out designing cars: You have to first learn how engines work and the basics of aerodynamics and ergonomic for example.

---

My standard beginner resources post

---

First learn the language by working 2-5 "Learn C# in 30 days" type books cover to cover. Do a couple hundred on-line tutorial projects where you build what you're told to build, the way you are told to build it WITH AN EXPLANATION OF WHY so you can learn.

Then later you can start architecting your own simple stuff. Build a calculator. Build a DVD library program. Etc. Stuff that doesn't involve the complexity of a game. Then move up to games.



There are three routes people seem to take when learning programming.

• Just start trying to create programs
  
• Start taking apart other programs and try to figure out the language by reverse engineering
  
• Follow a guided learning course (school or self-teaching books)

For the life of me I can't figure out why people try 1 & 2. I strongly suggest taking the guided learning approach. Those book authors go in a certain order for a reason: They know what they're doing and they know the best order to learn the materials.

Quote

Where do I start?

You start by learning a coding language FIRST.
Learn to plan before you type.
THEN you start designing software with a purpose.


If this sounds like you

Newbie/Rookie said:

I have a little programming experience but I need to write ...

read this section

Spoiler

You need to start there. I can't say "I have little experience in speaking Russian, but I have been assigned to write a mystery novel in Russian. Can you help me?"

We can help you by saying "First learn basic programming and the language of C#. Then take on assignments." Could someone here write this program for you? Sure. Could someone here map out all the processes you need to follow and do the Software Design part of this in the slim hope you could code it from there? Sure. But we don't volunteer to do the job that you're either getting paid for, or getting a grade for. You may want to read this.

For now, just work on the lessons. Do a self-teaching book from cover to cover. Then consider writing a program.

Don't try to create a useful working program to fit a need of yours (or a for-pay contract) as your introduction to coding project. When you are learning to code you don't know enough to code a program, let alone know how to engineer the architecture of a program. It would be like saying "I don't know how to read sheet music, or play an instrument. I think I'll write a 3 act opera as my first learning experience."

I don't say this to be mean. We've seen lots of new coders take this approach and we know it doesn't work. Trying to design your own programs before you understand the basics of the code language you've chosen just leads to problems, frustrations, and 'swiss-cheese' education (lots of holes).

Otherwise, you can just jump to the resources here:
Some of the tutorials below are for C# or Java not C, C++, VB.NET [...]. But the conceptual stuff of classes, object oriented design, events etc. are not language specific and should give you enough guidance in theory of program development for you to be able to look-up specific code example in your chosen coding language.

---

Resources, references and suggestions for new programmers. - Updated Mar 2012

---

Spoiler

Quote

I already have a background in programming from this other software/technology/lanugage so I don't think I need to do tutorials

Here's how I look at doing tutorials even if one has a coding background that makes one think they don't need to do tutorials:

• If one's background really is enough to not need the tutorials, then they won't take long - So what's the harm?
  
• If the tutorials do take a while, then it might be time to re-think how much of one's old experience really applies to the new technology.
  
• There's no down-side. Every tutorial/series teaches something in a new way. Maybe you pick up a neat trick or a different approach to something that you already knew.

The stages of asking for homework help on a forum



But honestly, just typing away and seeing what pops up in Intellisense is going to make your self-education take 20 years. You can learn by trying to reverse engineer the language through banging on the keyboard experimentation - or you can learn by doing the tutorials and following a good "How to learn C#" book. There are so many great "How do I build my first application" tutorials on the web... There are dozens of "Learn C# in 21 days", "My first C# program" type books at your local book seller or even public library.

Beginner:

Java

Spoiler

Best beginner books
Reading and writting a file in Java

C#

Spoiler

C# Reading list by Eric Lipert

C# Fundamentals: Development for absolute beginners (video series)
Build a Program Now! in Visual C# by Microsoft Press, ISBN 0-7356-2542-5 is a terrific book that has you build a Windows Forms application, a WPF app, a database application, your own web browser.

Martyr2's mega project ideas list is a great place to start on developmental projectst that you can learn from; rather than trying to make something complex like a game as a self-teaching tool {that never works for anyone}

Visual Studio Keyboard Shortcuts

D.I.C. C# Resource page Start here
Intro to C# online tutorial then here...
C# control structures then here.
MSDN Beginner Developer video series
MSDN video on OOP principals, making classes, constructors, accessors and method overloading
MSDN Top guideline violations, know what to avoid before you do it.
Design patterns as diagrams

I hate sending people to another site when we have such good tutorials here, but this series shouldn't be overlooked.
Programming OOP in C# - Part 1
Programming OOP in C# - Part 2
Programming OOP in C# - Part 3
Programming OOP in C# - Part 4
Programming OOP in C# - Part 5

Writing a text file is always one of the first things people want to do, in order to store data like high-scores, preferences and so on.
Writing a text file tutorial.
Reading a text file tutorial.
.Split()ing a string

Have you seen the 500+ MSDN Code Samples? They spent a lot of time creating samples and demos. It seems a shame to not use them.

Intermediate:
Microsoft Events (webcasts and podcasts)
The tutorials below walk through making an application including inheritance, custom events and custom controls, object serialization and more.
Quick and easy custom events
Bulding an application - Part 1
Building an application - Part 2
Separating data from GUI - PLUS - serializing the data to XML
WPF version (WPF-MVVM data binding)
Passing values between forms/classes
Decouple your multi-threaded work from the GUI so forms don't hang

Working with environmental variables
'Why do we use delegates?' thread
And everyone always wants to connect to a database, right out of the gate so Database tutorials right here on DIC

C# Cookbooks
Are a great place to get good code, broken down by need, written by coding professionals. You can use the code as-is, but take the time to actually study it. These professionals write in a certain style for a reason developed by years of experience and heartache.

Everyone:
Debugging tutorial
Debugging tips
Debugging in detail
Great debugging tips
It still doesn't work, article

I urge you to work through the C# learning series here on DIC, and to work a self-teaching book from cover to cover before you even think about designing your own applications.
Microsoft Visual Studio Tips, 251 ways to improve your productivity, Microsoft press, ISBN 0-7356-2640-5 Has many, many great, real-world tips that I use all the time.

These are just good every-day references to put in your bookmarks.
MSDN C# Developers Center with tutorials
Welcome to Visual Studio
Free editions of Visual Studio 2010
Student editions of Visual Studio


Windows Presentation Foundation:
Create Animations Programmatically

Some of my common tips (some may apply more than others to your specific style):

• You have to program as if everything breaks, nothing works, the cyberworld is not perfect, the attached hardware is flakey, the network is slow and unreliable, the harddrive is about to fail, every method will return an error and every user will do their best to break your software. Confirm everything. Range check every value. Make no assumptions or presumptions.
  
  
• Take the extra 3 seconds to rename your controls each time you drag them onto a form. The default names of button1, button2... button54 aren't very helpful. If you rename them right away to something like btnOk, btnCancel, btnSend etc. it helps tremendously when you make the methods for them because they are named after the button by the designer.btnSend_Click(object sender, eventargs e) is a lot easier to maintain than button1_click(object sender, eventargs e)
  
  
• You aren't paying for variable names by the byte. So instead of variables names of a, b, c go ahead and use meaningful names like index, timeOut, row, column and so on. You should avoid 'T' for the timer. Amongst other things 'T' is commonly used throughout C# for Type and this will lead to problems. There are naming guidelines you should follow so your code confirms to industry standards. It makes life much easier on everyone around you, including those of us here to help. If you start using the standards from the beginning you don't have to retrain yourself later.
  You might want to look at some of the naming guidelines. Its a lot easier to start with good habits than to break bad habits later and re-learn.
  
  
  • Guidelines for names
    
  • Naming guidelines
    
  • Design guidelines for classes
  
  
  
• Try to avoid having work actually take place in GUI control event handlers. It is better to have the GUI handler call other methods so those methods can be reused and make the code more readable. This is also how you can send parameters rather than use excessive global variables. Get in this habit even if you are using WinForms because WPF works a lot under the idea of "commands" and this will get you working towards that. Think of each gester, control click, menu option etc. as a command to do something such as a command to SAVE. It doesn't matter where the command comes from, all sources should point at the same target to do the actual saving.
  
  Spoiler

  
  

  // All of this different triggering mechinisms call the same single [il]SavePreferences()[/il] method
  
  btnSave(object sender, eventargs e)
  {
      SavePreferences(preferencesPath);
  }
  
  <KeyboardShortcut control+s bound to save>
  <Touchscreen guesture swiping from lowerleft to upperright bound to save>
  
  SaveMenuItem(object sender, eventargs e)
  {
      SavePreferences(@"C:\prefs\test.txt");
  }
  
  SaveContextMenu(object sender, eventargs e)
  {
      SavePreferences();// No parameter method overload
  }
  
  FormMain_Closing(object sender, eventargs e)
  {
      if (IsDirty) SavePreferences();
  }
  

  
  
  
• Don't replace lines of code that don't work. Instead comment them out and put your new attemps below that. This will keep you from re-trying the same ideas over and over. Also, when you come back to us saying "I've tried this 100 different ways and still can't get it", we can actually see what you tried. So often a failed attempt is very very close and just needs a little nudge in the right direction. So if we can say "See what you did in attempt 3... blah blah" it helps a lot
  
  
  Spoiler

  // Try #1 - May 1, 0900hrs
  //    code
  //    code  
  //    code
  // Try #2 - May 2, 1700hrs   Okay, plan B.  What if I do it *this* way
  //    code
  //    code  
  //    code
  // Try #14 - May 3, 0500hrs after 5 cans of RedBull.  Maybe I should get some sleep. I can't think of anything else but this last idea
      code
      code  
      code
  
  

  
  If you are using Visual Studio you can select a block of lines and hit control+k control+c (Kode Comment) to comment it out. control+k control+u (Kode Uncomment) to uncomment a selected block.
  
  
  
• I strongly suggest installing VMware or some other virtualization technology on your development PC so you can create a couple virtual computers for testing. This would allow you to debug and test inside: WinXP32, XP64, Vista, Win7x32, Win7x64... etc. without having to actually have 5 physical PC's. Visual Studio will let you send the debug directly into one of these virtual machines so you can watch it operate, check its variables, see the crashes and so on just as if it were debugging on your real machine.
  
  
• This can't be stressed enough in today's world of cell phone messaging:
  Don't use txt/sms/leet/T9 speak like: u no, u r, dnt, wut i m do-n, coz, al gud, b4, ny1, sum1, please and so on like this guy:
  
  
  Spoiler

  dis not b d'hood dawg... You are sitting at a real keyboard with a real monitor, not a cell phone. You are not here texting your high school posse to come to your kegger after their shift at Taco Bell. You are here asking for help from senior coding professionals who graciously donate their valuable time to helping the next generation of coders with their chosen craft. Please try to show them, yourself and the industry some respect by writing at least at an eighth grade level. (IE: English not ebonics or SMS, real words, punctuation and so on). If you can't take your own problem/question seriously enough to write like an adult, then why would you expect anyone else to take it seriously?
  
  When you write a post you are presenting yourself. Your writing style is all you have to show others who you are and what you stand for. When I see posts filled with lack of capitalization, SMS text like 'Urself', lack of punctuation and so on; what I see is someone who just doesn't care to make even an eighth grade presentation of themselves. I also see that you feel we are not worth the effort. Posts that look like this show that you don't feel the person you are talking to is worth speaking to as an adult. If you show this level of contempt or apathy towards someone you are asking for help how can you expect to be taken seriously or expect to receive that expert's fullest attention and time to help you?