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Let's say that you have a SortedList with the Key as a string and the Value as a struct. Also, the string Key is one of the data elements in the struct. Example:
using System;
using System.Collections.Generic;
namespace SortedListStructure
{
public struct Product
{
public string model;
public string description;
public int weight;
public int height;
public int width;
public int length;
};
class Program
{
static void Main(string[] args)
{
SortedList<string, Product> sl = new SortedList<string, Product>();
Product test;
test.model = "1X-3PA2Q94";
test.description = "Tractor Motor Sensor";
test.weight = 3;
test.height = 3;
test.width = 3;
test.length = 3;
sl.Add(test.model, test);
string m = test.model;
if (sl.ContainsKey(m))
{
Console.WriteLine("Description: {0}, Weight: {1}", sl[m].description, sl[m].weight);
}
else
{
Console.WriteLine("{0} not found", m);
}
Console.ReadLine();
}
}
}
While this works, the model is stored twice (I think? Is it?), once for the Key and once as one of the elements of the Product Value. One way to eliminate this redundancy would be to leave model out of the Product struct, but assume that this is not preferable. What is the most efficient approach when the Key is part of the Value?
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Yes, the model is stored twice. But I think that is right and proper. I would not be happy removing "model" from "Product" as it is obviously a proper part of the data. Equally, it is a very sensible key for your sorted list.
You could save space (and maybe some processing time, but I doubt it) by using the hash value of the model string as the key, but then it is unlikely that the sort order would be the same. I assume you are using a SortedList because you want to iterate in model order - so the model itself has to be the key.
I would live with this. Removing "model" from "Product" means that that infromation is incomplete when processing in methods that don't know about your list.
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Yes, removing model from Product should be considered off the table. I was just wondering (purely hypothetical  ) if there was a more elegant solution in which rather than having two separate lists of models, if somehow the Key referenced the model within product. I don't know if this is actually worth the trouble or even possible. It is not necessary to work but would be nice in terms of memory overhead. You could imagine a scaled up version of this problem in which the Key itself is a big complex struct or object and the Value is an even bigger struct or object that has the Key as one of its data elements (don't know how often this would actually come up since big numbers can index anything).
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Yes, when it gets scaled up it is a problem. I think then that you have to come up with a hashing scheme which preserves your sort order, and use that as the key instead. The only other way I can think of immediately is to use an unsorted list, and sort it by model. Yeuch.
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Hi,
the content of the "model" string, i.e. the actual characters, are stored only once. What is stored twice is the reference to the string, which takes 4 or 8 bytes depending on Win32/Win64; so the penalty for having the key also in the struct is very low.
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
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I'd forgotten that (still not completely used to managed code hiding the details).
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Actually, you would only have redundant references to the Product model string when using the SortedList<K, T> type. The model string is not actually duplicated in memory. While I've never done any performance analysis of SortedList or any of the other .NET collection types, I think what you are doing now is probably your best solution.
If this isn't acceptable and you can use .NET 3.5, you could use LINQ to create a sorted List<T> that would only include your Product structs.
IList<Product> sl = (from p in ul
orderby p.model
select p).ToList<Product>();
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What I'm looking is a source code to show me how to make and use menus. Here's a
sample of what I have. and Some of it works and some of it doesn't
--------------------------------------------------------
//Main Menu
MainMenu:
terminal.ClearScreen();
terminal.WriteLine();
terminal.WriteLine("Welcome :" + name);
terminal.WriteLine("1) Game Menu");
terminal.WriteLine("2) N/A");
terminal.WriteLine("3) Help");
terminal.WriteLine("9) Quit");
terminal.TranslateFile("Menu.txt", true);
terminal.Write("Choice : (1,2,3 0r 9)");
int caseSwitch = terminal.ReadDigit();
switch (caseSwitch)
{
case 1:
Functions NewGame = new Functions();
NewGame.GameMenu();
goto MainMenu;
case 2:
terminal.WriteLine("Case 2");
goto MainMenu;
case 9:
break;
default:
terminal.WriteLine("Invalid Key");
terminal.PromptEnter("Press ENTER to Continue..");
goto MainMenu;
}
------------------------------------------------
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bigjoe11a wrote: Some of it works and some of it doesn't
Are we supposed to guess which parts work and which don't?
Every time you use a goto a kitten gets punched in the face. Why do you hate kittens so much?
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Ok, why not. LOL. I mean it doesn't work at all. When I press 1. it just returns to the menu. and so on. Or the default just loads.
DO you know of a sample source code that will show me how to do this the right way.
--------------------------------------------------------------------
MainMenu:
terminal.ClearScreen();
terminal.WriteLine();
terminal.WriteLine("Welcome :" + name);
terminal.WriteLine("1) Game Menu");
terminal.WriteLine("2) List Users");
terminal.WriteLine("3) Help");
terminal.WriteLine("9) Quit");
terminal.Write("Choice : (1,2,3 0r 9)");
int caseSwitch = terminal.ReadDigit();
switch (caseSwitch)
{
case 1:
Functions NewGame = new Functions();
NewGame.GameMenu();
goto MainMenu;
case 2:
terminal.WriteLine("Case 2");
goto MainMenu;
case 3:
Functions NewHelp = new Functions();
NewHelp.Help();
goto MainMenu;
case 9:
break;
default:
terminal.WriteLine("Invalid Key");
terminal.PromptEnter("Press ENTER to Continue..");
goto MainMenu;
}
-----------------------------------------
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Seriously, gotos are the biggest indicator in the world of poorly structured code. Code flow should be handle by conditionals and loops and I'm guessing that's the main cause of your problems. My beginners attempt would start like this:
Semi-Psuedo Code:
bool done = false;
while (!done)
{
int userInput = 0;
do
{
PrintMainMenu();
userInput = GetNextInput();
} while (!InputIsValid(userInput));
switch (userInput)
{
case 0:
PrintHelpMenu();
break;
case 1:
RunGamesMenu();
break;
case 2:
Console.WriteLine("Exiting");
done = true;
break;
}
}
P.S. put pre tags around code snippets to preserve formatting
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Thanks, Can you give me an idea about what the PrintMainMenu would look like and a sample of the code used to make it. Or make be I'm getting to old to program.
Thanks
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it would contain something like this (from your original post):
terminal.ClearScreen();
terminal.WriteLine();
terminal.WriteLine("Welcome :" + name);
terminal.WriteLine("1) Game Menu");
terminal.WriteLine("2) N/A");
terminal.WriteLine("3) Help");
terminal.WriteLine("9) Quit");
I just stuck a function there to save space in the post 
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Rule 1: Use the "code block" button below to preserve formatting. It makes things easier to read.
Rule 2: unless you are a seriously experienced programmer and there is a very good reason, do not use goto. It will earn you nothing but grief and abuse here.
Rule 3: Learn about loops. Learn about data types. Learn at least the basics of C#.
Rule 4: Learn there is a difference between "Console" and "Terminal" (one exists, the other doesn't)
Having said that, I'm in a good mood:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Demo
{
class Program
{
static void Main(string[] args)
{
string name;
Console.Write("Enter your name: ");
name = Console.ReadLine();
Console.WriteLine("\nWelcome : " + name);
Console.WriteLine("1) Game Menu");
Console.WriteLine("2) List Users");
Console.WriteLine("3) Help");
Console.WriteLine("9) Quit");
Console.Write("Choice : (1,2,3 or 9) ");
int i = 0;
do
{
string s = Console.ReadLine();
if (s == "")
{
continue;
}
i = s[0];
switch (i)
{
case '1':
Console.WriteLine("Game selected");
break;
case '2':
Console.WriteLine("List selected");
break;
case '3':
Console.WriteLine("Help selected");
break;
case '9':
Console.WriteLine("Quit selected");
break;
default:
Console.WriteLine("Invalid Key");
break;
}
}
while (i != '9');
}
}
}
This is not perfect (I threw it together from your code), but it has the advantage of working...
Now, for your homework, please post a complete explaination of how it works.
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>>Now, for your homework, please post a complete explaination of how it works
Home work. Grin. I haven't done any home work in over 30+ years. and to explaination of how it works. ? I have no idea. It mite take some time before I can even under stand what you did. Any chance I can get you to make a simple one.
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Oooo! That is a simple one!
I can't teach you C# - I haven't got the time - but I'll do what I can.
Have you got any tools yet (C# compiler, etc)? If not, go to microsoft.com and search for "C# 2008 Express download" - this will give you a free copy of the C# IDE, with all the tools you need to do nearly everything with C#.
Do get a book on C# - there are some good ones out there, but I am not sure what you would need for starters. There is a free one available here C# Yellow book[^] which is used by the University of Hull for 1st year CS students and should cover the language basics.
Now, what have we got:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Demo
{
class Program
{
static void Main(string[] args)
{
...
}
}
}
This is all overhead - it is automatically generated for you and provides a "framework" in which your program can run.
string name;
Console.Write("Enter your name: ");
name = Console.ReadLine();
All this does is declare a variable called "name" that can hold a string of text, prompt the user for his name, and read his response.
Console.WriteLine("\nWelcome :" + name);
Console.WriteLine("1) Game Menu");
Console.WriteLine("2) List Users");
Console.WriteLine("3) Help");
Console.WriteLine("9) Quit");
Console.Write("Choice : (1,2,3 or 9) ");
Print out the users selection of choices.
int i = 0;
do
{
...
}
while (i != '9');
This sets up a loop - the program will go around and around here until the variable "i" contains the value '9', then it will exit the loop.
string s = Console.ReadLine();
if (s == "")
{
continue;
}
Read the users menu selection into the variable "s", check that he didn't just press the ENTER key (if he did, ignore it and got back around the loop).
i = s[0];
switch (i)
{
case '1':
Console.WriteLine("Game selected");
break;
case '2':
Console.WriteLine("List selected");
break;
case '3':
Console.WriteLine("Help selected");
break;
case '9':
Console.WriteLine("Quit selected");
break;
default:
Console.WriteLine("Invalid Key");
break;
}
Get the first character of the users input into the variable "i" (not a nice way, but it matched your code) and decide what to do with it. The "switch (i)" line says "look at the contents of the variable 'i', and compare it against the examples I will give you. If you find one which matches, then perform the instructions between the ':' character and the word 'break'"
'//' says "whatever text is to the right of me, ignore it, it is just a comment for poeple to read rather than an instruction for the computer".
Hope this helps a bit - it is really difficult to know where to start!
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Hi! OriginalGriff,
Thank you very much. That was very easy for me to understand. It works. Thank You
Can you tell me how to make the loop into a hot key. Where the user doesn't have to press enter. Just the number
Thanks
Joe
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Replace
string s = Console.ReadLine();
if (s == "")
{
continue;
}
i = s[0];
with
ConsoleKeyInfo cki;
cki = Console.ReadKey(true);
i = (int) cki.Key;
(the "true" prevents the key being echoed to the display.)
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Thank you very much. That works
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I take it you spotted that one then... 
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Hello,
How can i activate the mouse whell scroll in a datagrid?
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Your question doesn't make any sense.
"Activate the mouse"?? What does that mean??
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Hello,
I have windows application with tabpages and datagrids.
When i resize the windows size (to full screen) the window resizes but the tabpages and datagrids no.
How can i do that all of them will be resized according the original window size?
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