So I have a Calculator GUI with:
2 textboxes for user inputted numbers,
1 button for adding these numbers together,
and 1 textbox for showing the result
However, I cannot seem to be able to do the coding part of this, here is what I have:
public partial class Calculator : Form
{
public string firstOperand;
public string secondOperand;
public string result;
public Calculator()
{
InitializeComponent();
}
private void Calculator_Load(object sender, EventArgs e)
{
}
private void FirstOperandTextBox_TextChanged(object sender, EventArgs e)
{
FirstOperandTextBox.Text = firstOperand;
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
SecondOperandTextBox.Text = secondOperand;
}
private void AddButton_Click(object sender, EventArgs e)
{
firstOperand + secondOperand = result;
}
For the addButton part, I am getting the error, "The left hand side of an assignment must be a variable, property, or indexer".
There are several problems with your code
You write your statements as you would write the equations in real life, ie 1 + 1 = 2. But in the code, you have to write it the other way around - you assign value to a variable, so you should have
result = firstOperand + secondOperand;
You try to add together string values. So if you had 1 and 1 in your operands, the result would be 11 and not 2 as you expect.
Assigning the value of the operands in the TextChanged event is unnecessary, and you can simply do the conversion in the buttons OnClick event.
Furthermore, since you only want numbers, and not text, you would be better off using NumericUpDown control, instead of TextBox. That will take care of wrong input for you (wrong input would be if user put some other characters in the TextBox, or empty value). If you use TextBox, you have to do some conversion from string first.
private void AddButton_Click(object sender, EventArgs e)
{
result = numericFirst.Value + numericSecond.Value;
}
Generally, for read only values, you would use Label and not TextBox, to show the result
private void AddButton_Click(object sender, EventArgs e)
{
result = numericFirst.Value + numericSecond.Value;
lblResult.Text = result.ToString();
}
In AddButton_Click, change firstOperand + secondOperand = result to firstOperand.Text + secondOperand.Text
You want your result to store the final value.
private void AddButton_Click(object sender, EventArgs e)
{
result = (Convert.ToInt32(firstOperand) + Convert.ToInt32(secondOperand)).ToString();
MyResultTextBox.Text=result;
}
private void AddButton_Click(object sender, EventArgs e)
{
int first = 0;
int second = 0;
//Use TryParse() method to avoid exceptions while parsing an invalid string
int.TryParse(FirstOperandTextBox.Text, out first);
int.TryParse(SecondOperandTextBox.Text, out second);
//in the left hand side of = operator, there **must** be a variable always.
result = first + second;
ResultTextBox.Text = result.ToString();
}
Related
I am making a calculation, but then I came up with the idea to automatically make that calculation as I fill in textBox1. How I can call that calculation that is inside button1_Click? I know how to copy to textBox2 what you wrote in textBox1, but my knowledge is to little for to call a whole if statement calculation to auto update Total inside textBox2 when I was writing numbers inside textBox1 without a button.
private void textBox1_TextChanged(object sender, EventArgs e) { }
private void textBox2_TextChanged(object sender, EventArgs e) { }
private void button1_Click(object sender, EventArgs e)
{
aantalgroep = int.Parse(textBox1.Text);
/* Wat er gebeurd bij RadioButton1 Checked */
if (radioButton1.Checked)
{
number = aantalgroep * 8;
textBox2.Text = number.ToString();
if (aantalgroep < 10)
textBox2.Text = number.ToString();
}
}
Go in design editor, click on your textbox, click on little lighting, find TextChanged and click on arrow pointing down (next to TextChanged field). There you will have enlisted your already created method named button1_Click, select it and voila. Every time you change text in textbox you will call you method to auto calculate.
For sanity's sake, you should probably move the logic out of the click handler, since you plan to call it from various places. Once you have the logic extracted, you can call it from anywhere you want.
private void textBox1_TextChanged(object sender, EventArgs e)
{
Calculate();
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
//You probably don't want to call Calculate here, due to infinite recursion
//Calculate();
}
private void button1_Click(object sender, EventArgs e)
{
Calculate();
}
private void Calculate()
{
aantalgroep = int.Parse(textBox1.Text);
/* Wat er gebeurd bij RadioButton1 Checked */
if (radioButton1.Checked) {
number = aantalgroep * 8;
textBox2.Text = number.ToString();
if (aantalgroep < 10) {
textBox2.Text = number.ToString();
}
}
}
So, I know that with a code snippet such as:
int x = 0; //class field variable
private void button1_Click(object sender, EventArgs e)
{
Label1.Text += (x++)%4 + 1;
}
a sequence of 12341234 is displayed on the form if the button is clicked 8 times.
My goal is to get 43214321 to display.
I'm able to get 32103210 with:
int x = 0; //class field variable
private void button1_Click(object sender, EventArgs e)
{
Label1.Text += 3-(x++)%4;
}
I'm also able to get 32143214 with:
int x = 1; //class field variable
private void button1_Click(object sender, EventArgs e)
{
Label1.Text += 4-(x++)%4 + ;
}
What am I doing wrong? And is there a general formula for this?
Note: My x DOES have to be initialized to 1.
Just change the formula to:
Label1.Text += 4-((x-1)++)%4;
Try using this formula:
5-(1+(x+++3)%4)
That is:
Label1.Text += (5-(1+(x+++3)%4)).ToString();
The first line of code that you've written is basically cycling between 3 to 1.
x=0;
Label1.Text += 3-(x++)%4;
x=0 || Output=3.
Label1.Text= 0+3-(0%4)=3
x=1 || Output=2.
Label1.Text= 0+3-(1%4)=2
x=2 || Output=1.
(Dry run as done above)
x=3 || Output=0.
(dry run as done above)
x=4 and the cycle repeats.
You could dry run your second line of code to understand why your answer comes the way it does, but to answer your question in concise:
int x = 0; //class field variable
private void button1_Click(object sender, EventArgs e)
{
Label1.Text += 4-(x++)%4;
}
The title was properly written wrong but i will explain currently i have 2 sets of three buttons linked to a label. when i press a button it will place a number in the label as a result what i want to do is after the first button is pressed and then a second is clicked i want the two scores to add together to make a total result in the label eg if i press "three of a kind" which equals 3 points then press "four of a kind" which equals 6 points i want a result of 9 in the label and then if i press "five of a kind" which equals 12 point the label would then read 18 ect can i get any help please there isnt any code to put in due to not finding anything i will put in how my buttons are linked to my labels.
Result
public class Result
{
}
private void button2_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(3)).ToString();
label6.Text = Convert.ToString(add);
}
private void button5_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(3)).ToString();
label7.Text = Convert.ToString(add);
}
private void button3_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(5)).ToString();
label6.Text = Convert.ToString(add);
}
private void button6_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(5)).ToString();
label7.Text = Convert.ToString(add);
}
private void button4_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(12)).ToString();
label6.Text = Convert.ToString(add);
}
private void button7_Click(object sender, EventArgs e)
{
String add = (Convert.ToInt32(12)).ToString();
label7.Text = Convert.ToString(add);
}
I didn't quite understand the question, but I would suggest you to read about WPF and the MVVM mechanism to sync the data between the UI and the data.
What you're doing is writing a lot of code-behind code that is duplicated over and over and is doing a lot of unnecessary work (you convert a number to Int, then convert the result to string and then convert it again to string)
This function can be used to do the work property and efficiently once:
private void UpdateLabelText(Label label, int number) {
label.Text = number.ToString();
}
And use this method whenever you need to update the text in your label.
You have to cast the value of label.Text to int then add the value and then recast to string:
private void button6_Click(object sender, EventArgs e)
{
AddToLabel(label7, 12);
}
void AddToLabel(Label label, int value)
{
var n = int.Parse(label.Text); // convert the actual value of label.Text to int
var add = n + value; // add the increment
label.Text = add.ToString(); // assign to label.Text
}
I am very new to programming and I am trying to do that every time you click a button, it adds one to the value of an int and shows it in a textbox. My code is:
private void button1_Click(object sender, EventArgs e)
{
int a = 100;
a++;
txtBox1.Text = a.ToString();
}
So when I click the button it shows in the text box 101, but when I click it again, I want the textbox to show 102 and 103 etc etc. Any ideas? I assume it's very easy and using some variation of a loop but I have tried a few things and nothing seems to work. Any tips would be greatly appreciated! Thanks.
You have to store your value outside of Method Body.
private int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
What you did in your program is anytime you clicked the button, new Integer a was declared with value of 100, then you are increasing it by 1 and that's why you always seen '101'.
In your code you delcare a and assign a value to it over and over again every time you click on the button.
You should declare the variable outside of button1_Click method:
class Window1
{
int a = 100;
....
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
}
You need to declare a as a member of the class containing your method:
private int _a = 100;
private void button1_Click(object sender, EventArgs e)
{
_a++;
txtBox1.Text = _a.ToString();
}
If you don't do that, you will have a new instance every time the button is clicked, so you will always see 101 in your text box.
It is possible not to create global fields and store count of clicks inside the textbox.
This is especially convenient if you have several buttons.
private void button1_Click(object sender, EventArgs e)
{
if (txtBox1.Tag is int)
{
int a = (int)txtBox1.Tag;
a++;
txtBox1.Tag = a;
txtBox1.Text = a.ToString();
}
else
{
txtBox1.Tag = 100;
txtBox1.Text = 100;
}
}
int a = 100;
txtBox1.Text = a.ToString();
......
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
Placing int a = 100; inside the button1_Click(object sender, EventArgs e) will set a to 100 when each time function executing. If you need to have a counter place it outside from the function(Then it will initialize only once.) and increment it when executing the function.
Solution
int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
static int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
if you want to optimization your code than firstly set the textbox property text = 100 and write only one line code in button click event
private void button1_Click(object sender, EventArgs e)
{
txtBox1.Text = (Convert.ToInt32(txtBox1.Text) + 1).ToString();
}
as you know C# complie the code line by line and you have only one line code than it's give faster perfomance.
I am studying C# now, so i am making some kind of exercises to get used to C# syntax and learn better. I decided to make a calculator looking alike the normal windows calculator.
I created only one button "1" and one textbox.
I want to make this button write 1 in textbox when I press it and also make an int variable equal to the number in the textbook, to make the calculation later. So I can't either change "int a"'s value or change text in the textbox, it always shows 01, because a always equals to 0.
How can I make the program, both show the correct numbers and change the value of a correctly?
For example how can i make the program show eleven in the textbox when i press button twice and also change "int a"'s value to 11?
public partial class Form1 : Form
{
int a;
string Sa;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Sa = a.ToString() + "1";
textBox1.Text = Sa;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
}
private void button1_Click(object sender, EventArgs e)
{
textBox1.Text += "1";
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
a = Int32.Parse(textBox1.Text);
}
just it.. Change text on textBox every button click, and change variable a every textBox changed.
The value could then be set using
a = int.Parse(Sa);
textBox1.Text = Sa.TrimStart('0');
Although if you'd like to be more efficient about it,
a = a * 10 + 1;
not have Sa at all,
textBox1.Text = a.ToString();
If you run into integer overflows, you should use BigInteger.
You have several options:
Make int a nullable int. That way you can check if int is already set
int? a;
if ( a.HasValue )
{
}
else
{
}
Check if the Text property of textBox1 is empty (which means you don't have to append a to it)
if ( textBox1.Text == string.Empty)
{
}
else
{
}
public void btnOne_Click(object sender, EventArgs e)
{
txtDisplay.Text = txtDisplay.Text + btnOne.Text;
}
private void btnTwo_Click(object sender, EventArgs e)
{
txtDisplay.Text = txtDisplay.Text + btnTwo.Text;
}
// etc
for any button you want to append text to the text box set the click property to btn_Click then pt this code inside the method
private void btn_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
// This will assign btn with the properties of the button clicked
txt_display.Text = txt_display.Text + btn.Text;
// this will append to the textbox with whatever text value the button holds
}