I am making an algebra equation solver in which you enter 2 values and gives you the x value in a format of x + (value1)= (value2).
I figured out how to convert the data given in value1 and value2 to an integer but value one gets stuck in a private void and I can't use it outside of that void. How am I able to use value1 and value2 outside their respective private voids?
If you figured that out, how am I able to output the value of x into the program windows ( I'm creating a windows form application)?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace equation_solver
{
public partial class EquationSolver : Form
{
public EquationSolver()
{
InitializeComponent();
}
private void label1_Click(object sender, EventArgs e)
{
int z;
z = Convert.ToInt32(textBox1.Text);
z = int.Parse(textBox1.Text);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
int y;
y = Convert.ToInt32(textBox1.Text);
y = int.Parse(textBox1.Text);
}
}
}
Define y and z at class level and then use that in different events.
public partial class EquationSolver : Form
{
int z = 0; //class level
int y;
public EquationSolver()
{
InitializeComponent();
}
private void label1_Click(object sender, EventArgs e)
{
z = Convert.ToInt32(textBox1.Text);
z = int.Parse(textBox1.Text);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
y = Convert.ToInt32(textBox1.Text);
y = int.Parse(textBox1.Text);
}
}
In your current code since you are defining them inside a method they are limited to their scope and not visible outside of their scope.
EDIT: Just noticed one thing in your code (thanks to #Rahul Tripathi), you are converting TextBox values to int using Convert.ToInt32 and int.Parse, both would have the same effect, you can use either of them, just don't use both. You can also look at int.TryParse for parsing which is safer options since it will not raise the exception if parsing fails.
well the answer is as Habib said, as the variable is created inside the method, they are limited to that scope. if you want it to be available outside the method, create them outside the method.
second point i do not get why are you using those two even handlers. You could have used two text boxes for y and z and a third text box for x and a button for the result.
public partial class EquationSolver : Form
{
int x, y, z;
//Button in the form named btnSolveForX
private void btnSolveForX_Click(object sender, EventArgs e)
{
y = Int.Parse(txtY.Text);
z = Int.Parse(txtZ.Text);
x = z - y; // As x + y = z -> x = z -y
txtX.Text = z.ToString();
PrintResultInConsole();
}
//This function is to show that the x is still available
//outside the scope of the functions as it is created
//in the scope of class which means it is available anywhere
//inside the class.
private void PrintResultInConsole()
{
Console.WriteLine("Value of x is {0}",x);
}
}
Obviously it is better to use int.TryParse method instead of Int.Parse method to convert string to integer as there is no guarantee that the user is going to enter valid integer values.
Don't use a void method. Use a function to return the values you need. Then call that function when your event is fired. Here's an example that uses a generic collection:
//Here is the code that defines the method:
private double Sum(List<double> dataEntries)
{
double total = 0;
foreach (double d in dataEntries)
{
total += d;
}
return total;
}
// Here is the code that calls the method:
List<double> myList = new List<double>();
myList.Add(5.3);
myList.Add(3.34);
myList.Add(3.453);
double mySum = Sum(myList);
MessageBox.Show(mySum.ToString());
Related
I'm new to using C# and Visual Studio and i'm having a problem.
I'm trying to calculate a total value of three different multiplications using TextChanged event, so the total textbox updates every time I input a number in the textboxes I am using for the multiplications.
The total result in textbox4 is always 0. What am I doing wrong here?
Here is my code
public double multip_result1;
public double multip_result2;
public double multip_result3;
public void textbox1_TextChanged(object sender, EventArgs e)
{
double a, b, multip_result1;
a = Double.Parse(textbox1.Text);
b = 4.50;
multip_result1 = a * b;
total();
}
public void textbox2_TextChanged(object sender, EventArgs e)
{
double d, f, multip_result2;
d = double.Parse(textbox2.Text);
f = 6.50;
multip_result2 = d * f;
total();
}
public void textbox3_TextChanged(object sender, EventArgs e)
{
double h, j, multip_result3;
h = double.Parse(textbox3.Text);
j = 8.50;
multip_result3 = h * j;
total();
}
public void total()
{
double total_sum;
total_sum = multip_result1 + multip_result2 + multip_result3;
textbox4.Text = total_sum.ToString();
}
You have local variables multip_result1, multip_result2, multip_result3 which hide the fields with the same names, just remove them from the event handlers. So f.e. this:
double a, b, multip_result1;
becomes
double a, b;
otherwise you assign the calculated value to this local variable and the field remains 0.
If you want to assign to the field with the same name you could also use this.fieldName. But i'd strongly advise against using the same name to avoid issues like this.
In each of your change functions you're initializing multip_result1, multip_result2, and multip_result3.
This means it's not setting the more public versions, so when "total()" runs, all values are still zero.
"double a, b, multip_result1;" should be "double a, b;" and update the other functions accordingly.
I am trying to make number of TextBoxes according to number in TextBox1 and I want to use each TextBox value in my program. Their name becames txtbx0, txtbx1... but when I want to use in my program, it gives error "The name 'txtbx1' does not exist in the current context". How can I use them in my program?
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int y = Convert.ToInt32(textBox1.Text);
TextBox[] txtbx = new TextBox[y];
for (int i = 0; i < y; i++)
{
txtbx[i]= new TextBox();
txtbx[i].Location = new Point(20, i * 50);
txtbx[i].Size = new Size(100,50);
txtbx[i].Name = "txtbx"+i.ToString();
txtbx[i].Text = txtbx[i].Name;
flowLayoutPanel1.Controls.Add(txtbx[i]);
}
}
The way you have it right now, the textboxes could be accessed by using your array txtbx[whateverNumber]. In order to make them accessible outside of the method you posted, you'll need to make your txtbx array a class member instead of a method-scoped variable.
Something like:
class Form1 : Form
{
TextBox[] txtbx;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
int y = Convert.ToInt32(textBox1.Text);
txtbx = new TextBox[y]; // Now this references the class member
for (int i = 0; i < y; i++)
... etc.
}
}
Accessing them individually by name is not really feasible because you'd have to have class member variables for each of them, but you don't know up front how many to make. The array method like you're doing is much better. You can just access them in other methods using txtbx[0] through txtbx[numBoxes - 1].
I am a beginner with programming, so I'm sorry if this is a simple question. My program generates a random math problem (in addition) upon starting the application. The user enters what he/she believes is the answer. Next, the user clicks a button and text is displayed indicating whether the user's answer in correct or not.
I used the variables number1 and number2 in the Form Load event. How can I easily use them again in the button click event?
(Hopefully my code demonstrates what I was trying to do).....
public Form1()
{
InitializeComponent();
}
//New Method
private void GenerateRandoms()
{
// create random number variable
Random randomNumber = new Random();
int number1;
int number2;
number1 = randomNumber.Next(100, 501);
number2 = randomNumber.Next(100, 501);
randomProblemLeft.Text = number1.ToString();
randomProblemRight.Text = number2.ToString();
}
private void Form1_Load(object sender, EventArgs e)
{
// Call created method so random numbers are generated once form loads.
GenerateRandoms();
}
private void checkButton_Click(object sender, EventArgs e)
{
int rightAnswer; //The correct answer for the addition problem
int theirAnswer; // The answer given by the user
theirAnswer = int.Parse(answerInput.Text);
rightAnswer = (number1 + number2); //Trying to reuse these variables from first event????????????
if (rightAnswer == theirAnswer)
{
checkOutput.Text = "Yes, that is the correct answer!";
}
else
{
checkOutput.Text = "Sorry, that is incorrect!";
}
}
private void clearButton_Click(object sender, EventArgs e)
{
answerInput.Text = "";
checkOutput.Text = "";
GenerateRandoms();
}
private void exitButton_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
Local variables disappear as soon as they go out of scope (i.e. after the closing curly brace of the block where the local is declared is reached). Their values get discarded, with no way to recover them. That is why locals will not work in this case: you need to make them instance variables.
Declare the variables as private on the class level, remove the declaration from the method, and use instance variables in any of your methods:
private int number1; // Declared at the form level
private int number2;
private void GenerateRandoms()
{
// create random number variable
Random randomNumber = new Random();
number1 = randomNumber.Next(100, 501);
number2 = randomNumber.Next(100, 501);
...
}
private void checkButton_Click(object sender, EventArgs e)
{
int answer = number1 + number2;
...
}
the button click event actually has its own scope so you have a couple options. First declare variables number1 and number2 again in the button click event.
If you were to want the values to persist for some reason then you would want to declare number1 and number2 in the scope of the class. this would make them part of the object you create.
example
public class Form1()
{
private int number1;
private int number2;
//your functions here
}
You would make them "global" to the Form1 class by putting them at the same bracket level as the methods. This makes them member fields:
class Form1
{
private int number1;
private int number2;
// . . . the rest of the class goes here –
}
Doing it this way makes them available (in scope) to all of your classes methods. Putting the 'private' keyword on there makes it so no one else can access them.
I'm trying to create a mathematical game with a timer that calculates the number of correct questions within a specific time. Now I'm trying to increment an int value per button click if the answer is correct.
But it only increment once and sometimes does not increment:
private void button1_Click(object sender, EventArgs e)
{
int x = Randomnumber.Next(12);
int z = Randomnumber.Next(12);
int s = x * z;
int correct = 0;
//int cv = +correct;
textBox2.Text = x.ToString();
textBox3.Text = z.ToString();
if (s == Convert.ToInt32(textBox4.Text))
{
correct += 1;
numbercorrect.Text = correct.ToString();
}
}
your main form(i'm assuming you're using forms) is a class.
What I'd suggest is declaring a variable as a member of your forms class, and using that to hold the number of correct responses.
I'd imagine something like the following;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
int correct;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
//insert logic here
correct++;
}
}
}
You need to move int correct declaration to class scope. Otherwise with every click, you start with new variable.
int correct = 0; is scoped within the function. Move it outside the function as a class field. That way it will preserve its value instead of being reset to 0 during each click.
Try this:
private int correct = 0;
private void button1_Click(object sender, EventArgs e)
{
int x = Randomnumber.Next(12);
int z = Randomnumber.Next(12);
int s = x * z;
//int cv = +correct;
textBox2.Text = x.ToString();
textBox3.Text = z.ToString();
if (s == Convert.ToInt32(textBox4.Text))
{
correct ++;
numbercorrect.Text = correct.ToString();
}
You always start your count with 0, and never get the original value.
Now the variable holding the data is outside the function and initialized when the form loads.
Every time the button is clicked, correct is beging reset to zero.
Try declaring correct outside of the method.
Try look at code bellow:
int correct = 0;
tryParse(numbercorrect.Text, out correct);
So your code must be like:
private void button1_Click(object sender, EventArgs e)
{
int x = Randomnumber.Next(12);
int z = Randomnumber.Next(12);
int s = x * z;
int correct = 0;
int.tryParse(numbercorrect.Text, out correct);
//int cv = +correct;
textBox2.Text = x.ToString();
textBox3.Text = z.ToString();
if (s == Convert.ToInt32(textBox4.Text))
{
correct += 1;
numbercorrect.Text = correct.ToString();
}
I get the error below when I try to run the application I am sure its something simple but I dont see it. What I am trying to do it when I click a button I have labeled Play. I want to call a method called randomnumber. Then I want the results to be displayed in lblPickFive_1.
I have 2x2,Pick5,and powerball. Each random number is to be displayed in its own label I created.
For now I am just looking to get past the one of generating a random number and having it displayed in the one label then I will move onto the rest. And I am sure post more questions if I cant figure out the rest.
Error 1 No overload for method 'RandomNumber' takes '0' arguments
using System;
using System.Windows.Forms;
namespace LotteryTickets
{
public partial class Form1 : Form
{
/// <summary>
/// no-args Constructor
/// </summary>
public Form1()
{
InitializeComponent();
}
#region "== Control Event Handlers =="
private void Form1_Load(object sender, EventArgs e)
{
ClearWinningNumbers();
}
#endregion "== End Control Event Handlers =="
#region "== Methods ==";
/// <summary>
/// Clears the text inside the winning number "balls"
/// </summary>
private void ClearWinningNumbers()
{
this.lblPickFive_1.Text = "";
this.lblPickFive_2.Text = "";
this.lblPickFive_3.Text = "";
this.lblPickFive_4.Text = "";
this.lblPickFive_5.Text = "";
this.lblTwoByTwo_1.Text = "";
this.lblTwoByTwo_2.Text = "";
this.lblPowerball_1.Text = "";
this.lblPowerball_2.Text = "";
this.lblPowerball_3.Text = "";
this.lblPowerball_4.Text = "";
this.lblPowerball_5.Text = "";
this.lblPowerball_PB.Text = "";
}
#endregion "== End Methods ==";
private void cblTwoByTwo_2_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void cblTwoByTwo_1_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void btnPlay_Click(object sender, EventArgs e)
{
RandomNumber();
}
private void lblPickFive_1_Click(object sender, EventArgs e)
{
}
private void RandomNumber(int min, int max)
{
int num = new Random().Next(min, max);
lblPickFive_1.Text = num.ToString();
}
}
}
First, you shouldn't be newing up a random number generator every time you want a new random number. You should set the generator as a static or member variable and refer to it for each new number.
Second, you have to pass a min and a max to your RandomNumber method.
Well, your code doesn't match the error, but look at this:
private void btnPlay_Click(object sender, EventArgs e)
{
RandomNumber();
}
private void RandomNumber(int min, int max)
{
int num = new Random().Next(min, max);
lblPickFive_1.Text = num.ToString();
}
RandomNumber has two parameters, min and max. You haven't specified any in the call inside btnPlay_Click. That's what the compiler is complaining about. Change the call to something like:
RandomNumber(5, 10);
Even when that's fixed, you shouldn't create a new instance of Random each time. As it happens, it's unlikely to cause problems in this particular case as it's triggered by a user action, but you should read my article on random numbers to see what the problem is and how to avoid it.
You need to pass in values:
private void btnPlay_Click(object sender, EventArgs e)
{
RandomNumber();
}
should be:
private void btnPlay_Click(object sender, EventArgs e)
{
RandomNumber(0, 50000);
}
Your RandomNumber method takes two arguments.
If you want to call the method, you need to pass two arguments.
You're calling RandomNumber(); in btnPlay_Click but the RandomNumber method requires min and max.
Setup one Random object and initialize it once.
class Form1
{
...
Random rnd = new Random();
}
then to use it every time it is needed
void RandomNumber(int min, int max)
{
int num = rnd.Next(min, max);
...
}
What happens everytime you call new() it re-seeds the random number and you may end up with the same numbers over and over. I have had this happend to me and it killed me