C#•2y ago

❔ How to make this program into GUI application?

Hello guys! I have the following code:

 Console.WriteLine("Enter number: ");
int input = Convert.ToInt32(Console.ReadLine());
int a = 0; int b = 0;

while (a <= input)
{
    var mul = a * b;

    if (mul == input)
    {
        if (a > b)
            break;

        Console.WriteLine(a + " x " + b);
    }

    if (b == input)
    {
        b = 0;
        a++;
    }
    else
    {
        b++;
    }
}

 Console.WriteLine("Enter number: ");
int input = Convert.ToInt32(Console.ReadLine());
int a = 0; int b = 0;

while (a <= input)
{
    var mul = a * b;

    if (mul == input)
    {
        if (a > b)
            break;

        Console.WriteLine(a + " x " + b);
    }

    if (b == input)
    {
        b = 0;
        a++;
    }
    else
    {
        b++;
    }
}

It's for finding all possible multiplications of a given number which the user enters. For example: if I enter 2, the program shows: 2x1, if I enter 4, it shows 2x2 and 4x1 and so on... This program works in the C# console application but I want to try to make it work in GUI. My idea is to have 2 textboxes and 1 button. I enter the number in the first textbox and after I press the button, it must show the result in the second textbox.
However, I have never worked with GUI and I don't know what exactly do to. Does anybody have any idea where I should start?

95 Replies

Omnissiah•2y ago

if you double click on Generate in design mode vs will create the click event routine for you that's a start then you have to recover the text from the left textbox, i guess it would be textbox1.text or textbox2.text then you do your thing and then you assign text of the other textbox you could either concat a string where you console.writeline, or you could use a list instead

Pobiega•2y ago

this looks like winforms. Winforms is entirely event-driven so as suggested above, you'll double-click the button to create an "OnClick" event handler for that button in that handler, you write the code that should happen when the button is clicked. This will be more or less all your code from the console app, minus the console stuff since the controls belong in the same form, you will be able to access them via code by just using their names. Assuming the "input" field here is called "textbox1", you can access the content with textbox1.Text

gamer50082•2y ago

This is winforms Look like a win 7 version thou

NameOP•2y ago

like so?

Pobiega•2y ago

close but you can't use Console.ReadLine and Console.WriteLine since you have no console 🙂

NameOP•2y ago

right what should I use instead of console? richTextBox1? That's how the second textbox is called

Pobiega•2y ago

yeah you'll use the textboxes instead.

NameOP•2y ago

did it but then it shows these errors

Shinigami•2y ago

Remove the writeline You can search YouTube for basic winforms calculator app You'll get all the info you need If you have any doubts you can come back here anytime

NameOP•2y ago

calculator app, ok

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

NameOP•2y ago

not yet still working

Pobiega•2y ago

Can you show us what you have so far?

NameOP•2y ago

this is my code for the button. And It works when I start the form.

NameOP•2y ago

If the button is pressed, the second textbox shows a result. Now I need to do something about the user input

Pobiega•2y ago

You need to read the input from the textbox, not Console.ReadLine() this is a GUI application, you have no console

NameOP•2y ago

yeah, right. So instead of console I'll write the name of the first textbox, where the input is entered right?

Shinigami•2y ago

Yes

NameOP•2y ago

ah hold on that doesn't work, the textbox doesn't contain definition of Readline must use something else probably

Shinigami•2y ago

See this is winforms Readline and writeline is for console What's the name of the box you're entering your number? Whatever it is This how you'd do Int number = convert.toint32(yourboxname.text);

NameOP•2y ago

it's called textBox1

Shinigami•2y ago

textBox1.text then

NameOP•2y ago

i'll try it

Shinigami•2y ago

Also just a suggestion, whatever is the requirement try to do a simpler version of it For example in your case you wanted the multiples You could just do something like give an int and output would be input X 10 If that is working then you can work on your original logic and replace the initial simpler logic with it

NameOP•2y ago

ok I wrote this

int input = Convert.ToInt32(textBox1.text);

int input = Convert.ToInt32(textBox1.text);

abcyz•2y ago

You need to understand how classes and those components work. Follow some simple tutorial online first. Documentation might be confusing to start with

NameOP•2y ago

and it shows this error:

abcyz•2y ago

"Text" uppercase probably Because it's a property

NameOP•2y ago

ah thank you, works now

abcyz•2y ago

But you need to understand that using the Console class here doesn't make sense, since you aren't using a Console now. You are able to access the TextBox because you have access to it using the variable "textBox1" which references the Text Box in your GUI

NameOP•2y ago

yeah. doesn't make sense using console class when I'm not even using a console when I think about it. This code was from console application, though. I just needed to change few things for it to work with gui

NameOP•2y ago

ok so now when I enter a number it shows a multiplication

NameOP•2y ago

the problem is, it doesn't show all combinations. It must also show 6x1

Pobiega•2y ago

you are assigning the value, not adding to it

NameOP•2y ago

assigning the value

Pobiega•2y ago

a variable can only hold a single value

string name = "Steve";
name = "John";

string name = "Steve";
name = "John";

what does name contain now?

NameOP•2y ago

hmm... a value? and name must be variable

Pobiega•2y ago

I don't know if there is some kind of barrier here, its a fairly straight-forward question. What is the value of the variable called name after these two lines of code have run? @Name ?

Omnissiah•2y ago

i wrote "read textbox1.text" in the first answer...

abcyz•2y ago

He asked the question: "in this example what is the value of the variable "name"?

NameOP•2y ago

it must be the name he wrote

Pobiega•2y ago

And that name is... ?

NameOP•2y ago

John

Pobiega•2y ago

Correct. Now, when you do richTextBox.Text = $"{a} x {b}"; several times in a loop, what does that do? is it like the Steve/John example, or is it different?

NameOP•2y ago

that one will be a bit harder to answer

Pobiega•2y ago

Why? Im just asking, is it the same as the Steve/John example, or is it different?

NameOP•2y ago

I'll have to guess here no?

Pobiega•2y ago

incorrect. its exactly the same.

NameOP•2y ago

but it doesn't have any strings here

Pobiega•2y ago

so every time that line of code runs, it overwrites previous value thats why you only get one line

NameOP•2y ago

ok so... if I want the rest of the lines I must do something else?

Pobiega•2y ago

Yeah, you can't overwrite the current text you want to append new text now, luckily for you RichTextBox.AppendText exists. richTextBox1.AppendText("Hello");

NameOP•2y ago

Pobiega•2y ago

let me guess, you tried richTextBox1.AppendText = "your new value"; thus ignoring the message you actually replied to, which shows exactly how to use it.

NameOP•2y ago

no, hold on... let me check something...

NameOP•2y ago

yes, works now. Sort of. The problem was AppendText didn't paint properly at first

Pobiega•2y ago

you'll want to add a newline to your string

NameOP•2y ago

yes I'm trying now

Pobiega•2y ago

$"{a} x {b}\n"

NameOP•2y ago

it works wonders!

NameOP•2y ago

Now the only thing left to worry about is that when I enter anything different than a number or If I don't enter anything the program will break

Pobiega•2y ago

Thats easily fixed.

NameOP•2y ago

easily you say?

Pobiega•2y ago

yes. Im going to invoke a bot command that will paste a really long message dont be afraid, and read the entire message, okay? it will tell you how to solve this problem $tryparse

MODiX•2y ago

The TryParse pattern is considered best practice of parsing data from a string: - a TryParse method returns true or false to inform you if it succeeded or not, so you can use it directly in a condition, - since C# 7 you can declare a variable that will be used as an out argument inline in an argument list, - it forces you to check if the out argument contains valid data afterwards, Avoid: Convert.ToInt32 — it's a bad choice for parsing an int. It exists only for backwards compatibility reasons and should be considered last resort.

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

(Note: Convert does contain useful conversion methods: To/FromBase64String, To/FromHexString, ToString(X value, int toBase), ToX(string? value, int fromBase)) Avoid: int.Parse — you have to use a try/catch statement to handle invalid input, which is a less clean solution.

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

Use int.TryParse https://docs.microsoft.com/en-us/dotnet/api/system.int32.tryparse?view=net-5.0#System_Int32_TryParse_System_String_System_Int32__

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

Int32.TryParse Method (System)

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the operation succeeded.

NameOP•2y ago

interesting... so I added this code in the newly created section for the first textbox:

            int n;
            string output;


            do
            {
               
                output = Console.ReadLine();
            } while (int.TryParse(output, out n) == false);

            int n;
            string output;


            do
            {
               
                output = Console.ReadLine();
            } while (int.TryParse(output, out n) == false);

Pobiega•2y ago

.. what I thought we had established you can't use Console.ReadLine in a winforms app? all you need to do is check if the input was a valid number before continuing the method you can "stop" a method early by using return so in this case...

if(!int.TryParse(textBox1.Text, out var number))
{
  return;
}

if(!int.TryParse(textBox1.Text, out var number))
{
  return;
}

is enough after this block of code, you can safely use number as the parsed number

NameOP•2y ago

yes, right. And to replace the console I'll replace it with the name of the textbox, but what shall I use for ReadLine?

Pobiega•2y ago

Come on dude You already had that bit working. That hasn't changed. reading the input from the user is exactly the same as before, all we need to do is change how we parse it and I even wrote it in my example code 😦 I get a very strong feeling you dont really read the code I write

NameOP•2y ago

I got confused now. is this how it's supposed to look?

 int n;
            string output;


            do
            {
               
                output = Console.ReadLine();
            } while (int.TryParse(output, out n) == false);

            if (!int.TryParse(textBox1.Text, out var number))
            {
                return;
            }

 int n;
            string output;


            do
            {
               
                output = Console.ReadLine();
            } while (int.TryParse(output, out n) == false);

            if (!int.TryParse(textBox1.Text, out var number))
            {
                return;
            }

Pobiega•2y ago

what even is this? this isnt remotely your original code show me the code you had when you were at this point here

NameOP•2y ago

yeah, I got a little confused and it became messy now this code right here is for the section of the button:

   int input = Convert.ToInt32(textBox1.Text);
            int a = 0; int b = 0;

            while (a <= input)
            {
                var mul = a * b;

                if (mul == input)
                {
                    if (a > b)
                        break;

                    richTextBox1.AppendText($"{a} x {b}\n");
                 
                }

                if (b == input)
                {
                    b = 0;
                    a++;
                }
                else
                {
                    b++;
                }

   int input = Convert.ToInt32(textBox1.Text);
            int a = 0; int b = 0;

            while (a <= input)
            {
                var mul = a * b;

                if (mul == input)
                {
                    if (a > b)
                        break;

                    richTextBox1.AppendText($"{a} x {b}\n");
                 
                }

                if (b == input)
                {
                    b = 0;
                    a++;
                }
                else
                {
                    b++;
                }

the code I showed now is for the first textbox

Pobiega•2y ago

you dont want any code on the first textbox you just want the button to check if the value is valid before running

if (!int.TryParse(textBox1.Text, out int input))
{
    return;
}

int a = 0;
int b = 0;

while (a <= input)
{
    var mul = a * b;

    if (mul == input)
    {
        if (a > b)
            break;

        richTextBox1.AppendText($"{a} x {b}\n");
    }

    if (b == input)
    {
        b = 0;
        a++;
    }
    else
    {
        b++;
    }
}

if (!int.TryParse(textBox1.Text, out int input))
{
    return;
}

int a = 0;
int b = 0;

while (a <= input)
{
    var mul = a * b;

    if (mul == input)
    {
        if (a > b)
            break;

        richTextBox1.AppendText($"{a} x {b}\n");
    }

    if (b == input)
    {
        b = 0;
        a++;
    }
    else
    {
        b++;
    }
}

thats it.

NameOP•2y ago

ok I'll put the code in the button's secion then

Pobiega•2y ago

I only changed the first line of code. from

   int input = Convert.ToInt32(textBox1.Text);

   int input = Convert.ToInt32(textBox1.Text);

if (!int.TryParse(textBox1.Text, out int input))
{
    return;
}

if (!int.TryParse(textBox1.Text, out int input))
{
    return;
}

NameOP•2y ago

ok that's how the whole code looks:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace GUIProgram
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {



            if (!int.TryParse(textBox1.Text, out int input))
            {
                return;
            }

            int a = 0;
            int b = 0;

            while (a <= input)
            {
                var mul = a * b;

                if (mul == input)
                {
                    if (a > b)
                        break;

                    richTextBox1.AppendText($"{a} x {b}\n");
                }

                if (b == input)
                {
                    b = 0;
                    a++;
                }
                else
                {
                    b++;
                }
            }

        }

       
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace GUIProgram
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {



            if (!int.TryParse(textBox1.Text, out int input))
            {
                return;
            }

            int a = 0;
            int b = 0;

            while (a <= input)
            {
                var mul = a * b;

                if (mul == input)
                {
                    if (a > b)
                        break;

                    richTextBox1.AppendText($"{a} x {b}\n");
                }

                if (b == input)
                {
                    b = 0;
                    a++;
                }
                else
                {
                    b++;
                }
            }

        }

       
    }
}

NameOP•2y ago

but now the Form started to look like this

Pobiega•2y ago

you removed a bound eventhandler you need to go into the designer code and remove the connection

Pobiega•2y ago

clicking here should do that

NameOP•2y ago

thanks let's see Ah NICE! The program works now! 🙂 Just one small thing left:

NameOP•2y ago

If I enter a new number the previous result stays. Do you have any advice for that?

Pobiega•2y ago

you can clear the rich text box at the top of the click handler

NameOP•2y ago

I can't? So to close and run it again is the only way?

Pobiega•2y ago

no I suggest you clear it using code. at the top of the handler

NameOP•2y ago

at the top of the handler, ok

Pobiega•2y ago

or after you have confirmed that the input is valid, that works too so you dont clear unless there will be new results

NameOP•2y ago

yes that's the plan

Pobiega•2y ago

okay, so clear the textbox directly after you have done TryParse

NameOP•2y ago

I'll try to use this

 richTextBox1.Text = String.Empty

 richTextBox1.Text = String.Empty

Pobiega•2y ago

That should work.

NameOP•2y ago

Yes! It works. Ok and that's a wrap. Thanks very much for the help, really appreciate it, I can sure say I learned a thing or 2 out of this situation. 🙂 I'm definitely going to spend some time learning the basics of C# at least 😄 Come to think of it, I may even start right now 😄

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity. Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ How to make this program into GUI application?