I'm trying to make a program in C# that basically functions based on the key a user presses (ex. X = Quit, D = Disconnect, etc;) by using Console.ReadKey(); in c#
The problem I'm running into is how to use the ReadKey info in a Switch statement.. Can someone help please? The code is below.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Switch_Test
{
class Program
{
static void Main()
{
Console.WriteLine("Welcome. Please enter your command: ");
string chinput;
int input;
bool activated = false;
input = Console.ReadKey();
chinput = Convert.ToChar(input);
switch (chinput)
{
case 'x':
{
Console.WriteLine("You pressed x...");
break;
}
case 'y':
{
Console.WriteLine("You pressed y..");
break;
}
case 'd':
{
if (activated != true)
{
Console.WriteLine("Please activate first!");
break;
}
else
{
Console.WriteLine("Active..");
break;
}
}
case 'a':
{
if (activated != true)
{
activated = true;
Console.WriteLine("Activating..");
break;
}
else
{
activated = false;
Console.WriteLine("Deactivating.");
break;
}
}
default:
Console.WriteLine("Unknown Command.");
break;
}
}
}
}
I know that's probably really wrong but I originally started with Console.ReadLine(); , the only difference is I want it to activate a function when you press a single key rather than having to hit enter or being able to type in different keys. Thanks in advance!
First of all, Convert.ToChar() doesn't work on ConsoleKeyInfo structure, so that's why you have problems, this conversion will throw an Exception.
You don't have to convert your key to character, instead, you can switch on .Key property, which is an enumerable that contains every key:
var input = Console.ReadKey();
switch (input.Key) //Switch on Key enum
{
case ConsoleKey.X:
break;
case ConsoleKey.Y:
break;
}
Edit:
You can also use input.KeyChar to get what you tried first - character, then you can switch on it if you want to, but it's harded to switch on different keys like arrows etc.
If you care if letter is capital/small, you can use .KeyChar or use .Key with .Modifiers to check if shift key was pressed when user typed the letter
You can simply take input as:
char input=Console.ReadKey().KeyChar;
using Console.ReadKey() returns a type of a struct ConsoleKeyInfo. so you need to recieve the return in a variable from this type.
Then switch on the Key enumrator, that has all characters.
ConsoleKeyInfo chinput = Console.ReadKey();
switch (chinput.Key)
{
case ConsoleKey.X:
{
Console.WriteLine("You pressed x...");
break;
}
case ConsoleKey.Y:
{
Console.WriteLine("You pressed y..");
break;
}
case ConsoleKey.D:
{
if (activated != true)
{
Console.WriteLine("Please activate first!");
break;
}
else
{
Console.WriteLine("Active..");
break;
}
}
case ConsoleKey.A:
{
if (activated != true)
{
activated = true;
Console.WriteLine("Activating..");
break;
}
else
{
activated = false;
Console.WriteLine("Deactivating.");
break;
}
}
default:
Console.WriteLine("Unknown Command.");
break;
}
Related
I'm trying to make a question repeat if the input isn't right. Here's the code:
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
Boolean input = true;
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
break;
case "bob":
Console.WriteLine("you chose a bob");
break;
}
How do I make it if it isn't one of the two answers it reasks the question?
Use the default case.
If none of the cases in a switch statement match, the default case runs.
Here's an example.
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
switch (userInput)
{
case "joe":
// ...
break;
case "bob":
// ...
break;
default:
// This runs if userInput is neither "joe" nor "bob"
}
Then you can make a method that writes choose a name to the console, takes the user's input, and runs the switch statement - and the default case would call the same method.
void GetName()
{
// Write "choose a name" to the console
// Take the user's input
switch (userInput)
{
case "joe":
// ...
break;
case "bob":
// ...
break;
default:
GetName();
return;
}
}
You need a loop (either while or do-while) to repeat the iteration but not a switch-case.
While switch-case is used to control the flag (isCorrectInput) that stops the loop.
bool isCorrectInput = false;
do
{
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
isCorrectInput = true;
break;
case "bob":
Console.WriteLine("you chose a bob");
isCorrectInput = true;
break;
}
} while (!isCorrectInput);
Reference
Iteration statement
You should use a bool variable, that will determine whether you need to repeat the logic or not. Combine it with a loop and you get this:
bool keepAsking = true;
while (keepAsking)
{
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
Boolean input = true;
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
keepAsking = false;
break;
case "bob":
Console.WriteLine("you chose a bob");
keepAsking= false;
break;
}
}
You can try something like this. BUt you need to slightly change your code.
class XYZ
{
static void Main(string[] args)
{
GetData()
}
}
static void GetData()
{
string userInput = Console.ReadLine();
checkcondition(userInput);
}
static void checkcondition(userInput)
{
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
break;
case "bob":
Console.WriteLine("you chose a bob");
break;
default:
GetData();
break;
}
}
You can also achieve the same results using a smaller code but with a while loop instead of switch statement
while(true){
Console.Write("Choose a Name: ");
var name = Console.ReadLine().ToLower();
if(name == "joe" || name == "bob"){
Console.WriteLine("You chose a " + name + "!");
break;
}else{
Console.WriteLine("Invalid Selection, Try Again");
}
}
Understanding:
A Programm for someone that just started going to the Gym. (I'm trying
to learn c#)
First, the User fills out his Name, Age, Gender, Weight Height.
Then The user Picks a Goal.
To get a better understanding, something along these lines happens. (after the steps above)
if (Goal.GoalStatusGainWeight == true && Console.ReadLine() == "y")
{
Console.Clear();
InitFiveByFive();
//Caluclate Calories based on Gender and Goal
GainWeight.ShowFoodsToGainWeight();
Nutrition.CalcuateCalories();
ExitToMenu();
}
This is where my Problem is:
private static void ExitToMenu()
{
Console.WriteLine("PRESS ESC To Return to the MENU");
var input = Console.ReadKey();
if (input.Key == ConsoleKey.Escape)
{
Console.Clear();
InitMenu();
}
}
Problem is when I get back to the Menu. And Input something again.
do
{
var userInput = Console.ReadKey();
try
{
switch (userInput.Key)
{
case ConsoleKey.D1:
Console.Clear();
InitUser();
InitGoals();
Stats.ShowStats = true;
Menu.ShowMenu = false;
break;
case ConsoleKey.D2:
Console.Clear();
Menu.Disclamer();
Menu.ShowMenu = true;
Menu.ShowDiscalmer = true;
break;
case ConsoleKey.D3:
Console.Clear();
Menu.MadeBy();
break;
default:
Console.Clear();
InitMenu();
break;
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
throw;
}
if (Menu.ShowMenu == false)
{
Menu.MenuOnOff = false;
}
} while (Menu.MenuOnOff == true);
It will not take the input again. And I'm not sure how to handle the situation.
After the User Exists the 'Workout Plan' back to the Menu, and I try to Press 1 again, (case ConsoleKey.D1:) my Console App just closes.
I hope I got everything that you need to help me if there's something missing please let me know.
Thank you.
When I'm doing the code without the goto command it works, but when I add the :Start it get an 8 error.
Here is the relevant code:
:Start
Console.Write("Do you want the yes or no?");
string what = Console.ReadLine();
switch (what)
{
case "yes":
Console.WriteLine("You choose yes");
break;
case "no":
Console.WriteLine("You choose no");
break;
default:
Console.WriteLine("{0},is not a word",what);
goto Start;
}
The correct syntax is Start:. But, instead of goto, you should set this up in a loop:
bool invalid = true;
while (invalid)
{
Console.Write("Do you want the yes or no?");
string what = Console.ReadLine();
switch (what)
{
case "yes":
Console.WriteLine("You choose yes");
invalid = false;
break;
case "no":
Console.WriteLine("You choose no");
invalid = false;
break;
default:
Console.WriteLine("{0},is not a word",what);
}
}
Try "Start:" instead of ":Start"
like this:
Start:
Console.Write("Do you want the yes or no?");
string what = Console.ReadLine();
switch (what)
{
case "yes":
Console.WriteLine("You choose yes");
break;
case "no":
Console.WriteLine("You choose no");
break;
default:
Console.WriteLine("{0},is not a word", what);
goto Start;
}
http://msdn.microsoft.com/en-us/library/aa664740(v=vs.71).aspx
The correct syntax for a label is Start:, not :Start
You can refactor your code to omit the goto statement instead (better):
bool continue = true;
while (continue) {
Console.Write("Do you want the yes or no?");
string what = Console.ReadLine();
switch (what)
{
case "yes":
Console.WriteLine("You choose yes");
continue = false;
break;
case "no":
Console.WriteLine("You choose no");
continue = false;
break;
default:
Console.WriteLine("{0}, is not a word",what);
break;
}
}
I am not understanding what is going on in my case statement to determine if I want to redo the users input. Should I make another loop outside of my while loop? I attempted such and my case statement becomes unreachable code. Maybe I am not understanding case-switch statements.
class Program
{
static void Main(string[] args)
{
string _a = "";
constructor con = new constructor();
Console.WriteLine("Enter enter exit to end the program...");
Console.WriteLine("Enter C for constructor, M for method, A for an array...");
Console.WriteLine("Please reference source code to have full details and understanding...");
bool control = true;
while (control)
{
_a = Console.ReadLine();
switch (_a.ToUpper())
{
case "EXIT":
Console.WriteLine("Thank you for using AJ's program...");
control = false;
break;
case "C":
Console.WriteLine(con.a);
Console.WriteLine("Would you like to test another scenario?");
Console.ReadLine();
if (_a.ToUpper() == "Y")
{
Console.ReadLine();
return;
}
control = false;
break;
case "M":
control = false;
metroid();
break;
case "A":
control = false;
Array();
break;
default: Console.WriteLine("No match");
break;
}
}
}
public class constructor
{
public string a = "This is a constructor!";
}
static public void metroid()
{
string b = "This is a method!";
Console.WriteLine(b);
}
static public void Array()
{
try
{
Console.WriteLine("This is a random array. Please enter the size.");
string sSize = Console.ReadLine();
int arraySize = Convert.ToInt32(sSize);
int[] size = new int[arraySize];
Random rd = new Random();
Console.WriteLine();
for (int i = 0; i < arraySize; i++)
{
size[i] = rd.Next(arraySize);
Console.WriteLine(size[i].ToString());
}
}
catch (System.FormatException)
{
Console.WriteLine("Not correct format, restarting array process.");
Array();
}
}
}
}
Here's what I came up with. You had too many ways of exiting your loop, so I removed all of the control = false lines except where the user typed "EXIT"
Also, in case "C" you return out of the method if they choose "Y", I changed that to continue so that the loop would continue.
Finally, I moved the 3 instruction statements into the loop, so when the user hit "Y" it would print those again.
static void Main(string[] args)
{
string _a = "";
constructor con = new constructor();
bool control = true;
while (control)
{
Console.WriteLine("Enter enter exit to end the program...");
Console.WriteLine("Enter C for constructor, M for method, A for an array...");
Console.WriteLine("Please reference source code to have full details and understanding...");
_a = Console.ReadLine();
switch (_a.ToUpper())
{
case "EXIT":
Console.WriteLine("Thank you for using AJ's program...");
control = false;
break;
case "C":
Console.WriteLine(con.a);
Console.WriteLine("Would you like to test another scenario?");
_a = Console.ReadLine(); //<==problem #1 you didnt set your var name
if (_a.ToUpper() == "Y")
{
continue; //<==problem #2 return exits the program, continue, just keeps going
}
control = false;
break;
case "M":
metroid();
break;
case "A":
Array();
break;
default:
Console.WriteLine("No match");
break;
}
}
}
I think you should considering goto in this case. Yes you need to put some extra effort, but it will help you overcoming the While loop.
A sample below:
switch (_a.ToUpper())
{
case "EXIT":
Console.WriteLine("Thank you for using AJ's program...");
control = false;
// execute goto when your all line executes successfully
goto case "New";
case "New":
// some logic
}
See working sample here Goto-Switch
string NewInput= Console.ReadLine();
if (NewInput.ToUpper() == "Y")
{
//print some thing with console.writeline
//if after this you want to restart the loop then instead of return use
continue;
}
Try putting the Console.Writeline inside the while loop like this:
static void Main(string[] args)
{
bool control = true;
while (control)
{
Console.WriteLine("Enter enter exit to end the program...");
Console.WriteLine("Enter C for constructor, M for method, A for an array...");
Console.WriteLine("Please reference source code to have full details and understanding...");
string _a = Console.ReadLine();
switch (_a.ToUpper())
{
case "EXIT":
Console.WriteLine("Thank you for using AJ's program...");
control = false;
break;
case "C":
Console.WriteLine("press c");
Console.WriteLine("Would you like to test another scenario?");
Console.ReadLine();
if (_a.ToUpper() == "Y")
{
Console.ReadLine();
return;
}
control = false;
break;
case "M":
control = false;
metroid();
break;
case "A":
control = false;
Array();
break;
default: Console.WriteLine("No match");
break;
}
}
}
Additional reading about switch here and here.
Just add comment for the result, thanks. Hope this helped!
may be you want to change
Console.ReadLine();
if (_a.ToUpper() == "Y")
{
Console.ReadLine();
return;
}
as
_a = Console.ReadLine();
if (_a.ToUpper() == "Y")
{
_a = Console.ReadLine();
continue;
}
I need to close the console when the user selects a menu option.
I tried using close() but it did not work..
how can I do this?
Environment.Exit and Application.Exit
Environment.Exit(0) is cleaner.
http://geekswithblogs.net/mtreadwell/archive/2004/06/06/6123.aspx
By close, do you mean you want the current instance of the console app to close, or do you want the application process, to terminate? Missed that all important exit code:
Environment.Exit(0);
Or to close the current instance of the form:
this.Close();
Useful link.
You can Try This
Application.Exit();
//How to start another application from the current application
Process runProg = new Process();
runProg.StartInfo.FileName = pathToFile; //the path of the application
runProg.StartInfo.Arguments = genArgs; //any arguments you want to pass
runProg.StartInfo.CreateNoWindow = true;
runProg.Start();
//How to end the same application from the current application
int IDstring = System.Convert.ToInt32(runProg.Id.ToString());
Process tempProc = Process.GetProcessById(IDstring);
tempProc.CloseMainWindow();
tempProc.WaitForExit();
return; will exit a method in C#.
See code snippet below
using System;
namespace Exercise_strings
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Input string separated by -");
var stringInput = Console.ReadLine();
if (string.IsNullOrWhiteSpace(stringInput))
{
Console.WriteLine("Nothing entered");
return;
}
}
So in this case if a user enters a null string or whitespace, the use of the return method terminates the Main method elegantly.
So you didn't say you wanted the application to quit or exit abruptly, so as another option, perhaps just have the response loop end out elegantly. (I am assuming you have a while loop waiting for user instructions. This is some code from a project I just wrote today.
Console.WriteLine("College File Processor");
Console.WriteLine("*************************************");
Console.WriteLine("(H)elp");
Console.WriteLine("Process (W)orkouts");
Console.WriteLine("Process (I)nterviews");
Console.WriteLine("Process (P)ro Days");
Console.WriteLine("(S)tart Processing");
Console.WriteLine("E(x)it");
Console.WriteLine("*************************************");
string response = "";
string videotype = "";
bool starting = false;
bool exiting = false;
response = Console.ReadLine();
while ( response != "" )
{
switch ( response )
{
case "H":
case "h":
DisplayHelp();
break;
case "W":
case "w":
Console.WriteLine("Video Type set to Workout");
videotype = "W";
break;
case "I":
case "i":
Console.WriteLine("Video Type set to Interview");
videotype = "I";
break;
case "P":
case "p":
Console.WriteLine("Video Type set to Pro Day");
videotype = "P";
break;
case "S":
case "s":
if ( videotype == "" )
{
Console.WriteLine("Please Select Video Type Before Starting");
}
else
{
Console.WriteLine("Starting...");
starting = true;
}
break;
case "E":
case "e":
Console.WriteLine("Good Bye!");
System.Threading.Thread.Sleep(100);
exiting = true;
break;
}
if ( starting || exiting)
{
break;
}
else
{
response = Console.ReadLine();
}
}
if ( starting )
{
ProcessFiles();
}