Методичка: Використання CheckBox, RadioButton, ComboBox

// Масив CheckBox для вибору інгредієнтів
CheckBox[] ingredients = { checkBoxCheese, checkBoxTomato, checkBoxPepperoni };
string selected = string.Join(", ", ingredients.Where(cb => cb.Checked).Select(cb => cb.Text));
MessageBox.Show("Обрано: " + selected);

string size = radioSmall.Checked ? "Мала" :
              radioMedium.Checked ? "Середня" : "Велика";
MessageBox.Show("Розмір: " + size);

string pizza = comboBoxPizza.SelectedItem.ToString();
MessageBox.Show("Вибрана піца: " + pizza);

Зробити замовлення

C# код комплексного проекту. Form1.Designer.cs (з GroupBox)

namespace PizzaOrderApp
{
    partial class Form1
    {
        private System.ComponentModel.IContainer components = null;

        private System.Windows.Forms.GroupBox groupIngredients;
        private System.Windows.Forms.CheckBox checkBoxCheese;
        private System.Windows.Forms.CheckBox checkBoxTomato;
        private System.Windows.Forms.CheckBox checkBoxPepperoni;
        private System.Windows.Forms.CheckBox checkBoxOlives;
        private System.Windows.Forms.CheckBox checkBoxMushrooms;

        private System.Windows.Forms.GroupBox groupSize;
        private System.Windows.Forms.RadioButton radioSmall;
        private System.Windows.Forms.RadioButton radioMedium;
        private System.Windows.Forms.RadioButton radioLarge;

        private System.Windows.Forms.GroupBox groupCrust;
        private System.Windows.Forms.RadioButton radioThin;
        private System.Windows.Forms.RadioButton radioThick;

        private System.Windows.Forms.GroupBox groupPizza;
        private System.Windows.Forms.ComboBox comboBoxPizza;

        private System.Windows.Forms.GroupBox groupCustomer;
        private System.Windows.Forms.TextBox textBoxTable;
        private System.Windows.Forms.TextBox textBoxSurname;

        private System.Windows.Forms.Button btnOrder;

        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null)) components.Dispose();
            base.Dispose(disposing);
        }

        private void InitializeComponent()
        {
            this.groupIngredients = new System.Windows.Forms.GroupBox();
            this.checkBoxCheese = new System.Windows.Forms.CheckBox();
            this.checkBoxTomato = new System.Windows.Forms.CheckBox();
            this.checkBoxPepperoni = new System.Windows.Forms.CheckBox();
            this.checkBoxOlives = new System.Windows.Forms.CheckBox();
            this.checkBoxMushrooms = new System.Windows.Forms.CheckBox();

            this.groupSize = new System.Windows.Forms.GroupBox();
            this.radioSmall = new System.Windows.Forms.RadioButton();
            this.radioMedium = new System.Windows.Forms.RadioButton();
            this.radioLarge = new System.Windows.Forms.RadioButton();

            this.groupCrust = new System.Windows.Forms.GroupBox();
            this.radioThin = new System.Windows.Forms.RadioButton();
            this.radioThick = new System.Windows.Forms.RadioButton();

            this.groupPizza = new System.Windows.Forms.GroupBox();
            this.comboBoxPizza = new System.Windows.Forms.ComboBox();

            this.groupCustomer = new System.Windows.Forms.GroupBox();
            this.textBoxTable = new System.Windows.Forms.TextBox();
            this.textBoxSurname = new System.Windows.Forms.TextBox();

            this.btnOrder = new System.Windows.Forms.Button();

            // 
            // groupIngredients
            // 
            this.groupIngredients.Text = "Інгредієнти";
            this.groupIngredients.Location = new System.Drawing.Point(20, 20);
            this.groupIngredients.Size = new System.Drawing.Size(140, 180);
            this.groupIngredients.Controls.Add(this.checkBoxCheese);
            this.groupIngredients.Controls.Add(this.checkBoxTomato);
            this.groupIngredients.Controls.Add(this.checkBoxPepperoni);
            this.groupIngredients.Controls.Add(this.checkBoxOlives);
            this.groupIngredients.Controls.Add(this.checkBoxMushrooms);

            this.checkBoxCheese.Text = "Сир"; this.checkBoxCheese.Location = new System.Drawing.Point(10, 20);
            this.checkBoxTomato.Text = "Помідори"; this.checkBoxTomato.Location = new System.Drawing.Point(10, 45);
            this.checkBoxPepperoni.Text = "Пепероні"; this.checkBoxPepperoni.Location = new System.Drawing.Point(10, 70);
            this.checkBoxOlives.Text = "Оливки"; this.checkBoxOlives.Location = new System.Drawing.Point(10, 95);
            this.checkBoxMushrooms.Text = "Гриби"; this.checkBoxMushrooms.Location = new System.Drawing.Point(10, 120);

            foreach (var cb in new [] { checkBoxCheese, checkBoxTomato, checkBoxPepperoni, checkBoxOlives, checkBoxMushrooms })
                cb.CheckedChanged += new System.EventHandler(this.InputChanged);

            // 
            // groupSize
            // 
            this.groupSize.Text = "Розмір піци";
            this.groupSize.Location = new System.Drawing.Point(180, 20);
            this.groupSize.Size = new System.Drawing.Size(120, 120);
            this.groupSize.Controls.Add(this.radioSmall);
            this.groupSize.Controls.Add(this.radioMedium);
            this.groupSize.Controls.Add(this.radioLarge);

            this.radioSmall.Text = "Мала"; this.radioSmall.Location = new System.Drawing.Point(10, 20);
            this.radioMedium.Text = "Середня"; this.radioMedium.Location = new System.Drawing.Point(10, 45);
            this.radioLarge.Text = "Велика"; this.radioLarge.Location = new System.Drawing.Point(10, 70);

            foreach (var r in new [] { radioSmall, radioMedium, radioLarge })
                r.CheckedChanged += new System.EventHandler(this.InputChanged);

            // 
            // groupCrust
            // 
            this.groupCrust.Text = "Тісто";
            this.groupCrust.Location = new System.Drawing.Point(180, 150);
            this.groupCrust.Size = new System.Drawing.Size(120, 70);
            this.groupCrust.Controls.Add(this.radioThin);
            this.groupCrust.Controls.Add(this.radioThick);

            this.radioThin.Text = "Тонке"; this.radioThin.Location = new System.Drawing.Point(10, 20);
            this.radioThick.Text = "Товсте"; this.radioThick.Location = new System.Drawing.Point(10, 45);

            foreach (var r in new [] { radioThin, radioThick })
                r.CheckedChanged += new System.EventHandler(this.InputChanged);

            // 
            // groupPizza
            // 
            this.groupPizza.Text = "Назва піци";
            this.groupPizza.Location = new System.Drawing.Point(320, 20);
            this.groupPizza.Size = new System.Drawing.Size(150, 70);
            this.groupPizza.Controls.Add(this.comboBoxPizza);

            this.comboBoxPizza.Items.AddRange(new object[] { "Маргарита", "Пепероні", "Гавайська" });
            this.comboBoxPizza.SelectedIndexChanged += new System.EventHandler(this.InputChanged);

            // 
            // groupCustomer
            // 
            this.groupCustomer.Text = "Клієнт";
            this.groupCustomer.Location = new System.Drawing.Point(320, 110);
            this.groupCustomer.Size = new System.Drawing.Size(180, 100);
            this.groupCustomer.Controls.Add(this.textBoxTable);
            this.groupCustomer.Controls.Add(this.textBoxSurname);

            this.textBoxTable.Width = 150;
            this.textBoxTable.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.textBoxTable_KeyPress);
            this.textBoxTable.TextChanged += new System.EventHandler(this.InputChanged);

            this.textBoxSurname.Width = 150;
            this.textBoxSurname.TextChanged += new System.EventHandler(this.InputChanged);

            // 
            // btnOrder
            // 
            this.btnOrder.Text = "Зробити замовлення";
            this.btnOrder.Location = new System.Drawing.Point(320, 220);
            this.btnOrder.Enabled = false;
            this.btnOrder.Click += new System.EventHandler(this.btnOrder_Click);

            // 
            // Form1
            // 
            this.ClientSize = new System.Drawing.Size(520, 270);
            this.Controls.Add(this.groupIngredients);
            this.Controls.Add(this.groupSize);
            this.Controls.Add(this.groupCrust);
            this.Controls.Add(this.groupPizza);
            this.Controls.Add(this.groupCustomer);
            this.Controls.Add(this.btnOrder);

            this.Text = "Замовлення піци";
        }
    }
}

// Повний C# код з активацією кнопки лише після заповнення всіх полів
using System;
using System.Linq;
using System.Windows.Forms;

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

        private void InputChanged(object sender, EventArgs e)
        {
            btnOrder.Enabled = (checkBoxCheese.Checked || checkBoxTomato.Checked || checkBoxPepperoni.Checked ||
                                checkBoxOlives.Checked || checkBoxMushrooms.Checked)
                               && (radioSmall.Checked || radioMedium.Checked || radioLarge.Checked)
                               && (radioThin.Checked || radioThick.Checked)
                               && comboBoxPizza.SelectedIndex >= 0
                               && !string.IsNullOrWhiteSpace(textBoxTable.Text)
                               && !string.IsNullOrWhiteSpace(textBoxSurname.Text);
        }

        private void textBoxTable_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
                e.Handled = true;
        }

        private void btnOrder_Click(object sender, EventArgs e)
        {
            var ingredients = "";
            if (checkBoxCheese.Checked) ingredients += "Сир, ";
            if (checkBoxTomato.Checked) ingredients += "Помідори, ";
            if (checkBoxPepperoni.Checked) ingredients += "Пепероні, ";
            if (checkBoxOlives.Checked) ingredients += "Оливки, ";
            if (checkBoxMushrooms.Checked) ingredients += "Гриби, ";
            ingredients = ingredients.TrimEnd(' ', ',');

            string size = radioSmall.Checked ? "Мала" :
                          radioMedium.Checked ? "Середня" : "Велика";

            string crust = radioThin.Checked ? "Тонке" : "Товсте";

            string pizza = comboBoxPizza.SelectedItem.ToString();
            string table = textBoxTable.Text;
            string surname = textBoxSurname.Text.Trim();

            int price = size == "Мала" ? 100 : size == "Середня" ? 150 : 200;
            price += ingredients.Split(',').Length * 20;

            MessageBox.Show($"Замовлення: {pizza}, {size} пицца, {crust} тісто, " +
                            $"з {ingredients}. Стол: {table}, Прізвище: {surname}. Ціна: {price} грн");
        }
    }
}

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Задачи для самостоятельной работы