Practical 1 (A) Working with basic C# and ASP .NET

Описание: Create an ASP.NET application that takes 4 integer inputs from the user and displays the product.

🟦 STEP 1 — Create a New ASP.NET Web Application

Open Visual Studio

Click Create a new project

Select ASP.NET Web Application (.NET Framework)

Click Next

Give a name → ProductOfNumbers

Choose:

Framework: .NET Framework 4.x

Template: Empty (check Web Forms)

Click Create

This creates your project.

🟦 STEP 2 — Add a Web Form

Right-click the project → Add → Web Form

Name it: Default.aspx

Click Add

Now you have two files:

Default.aspx

Default.aspx.cs (code-behind file)

🟦 STEP 3 — Design the UI (Default.aspx)

You need:

4 TextBoxes

1 Button

1 Label to show result

Replace your Default.aspx content with:

<form id="form1" runat="server">
<div>
<h2>Enter Four Numbers</h2>

<asp:TextBox ID="txtNum1" runat="server"></asp:TextBox><br /><br />
<asp:TextBox ID="txtNum2" runat="server"></asp:TextBox><br /><br />
<asp:TextBox ID="txtNum3" runat="server"></asp:TextBox><br /><br />
<asp:TextBox ID="txtNum4" runat="server"></asp:TextBox><br /><br />

<asp:Button ID="btnCalculate" runat="server" Text="Calculate Product"
OnClick="btnCalculate_Click" />

<h3>Product: <asp:Label ID="lblResult" runat="server"></asp:Label></h3>
</div>
</form>



✔ This creates your input boxes and button.

🟦 STEP 4 — Write the C# Code (Default.aspx.cs)

Double-click the Calculate Button or add the code manually:

protected void btnCalculate_Click(object sender, EventArgs e)
{
int a = int.Parse(txtNum1.Text);
int b = int.Parse(txtNum2.Text);
int c = int.Parse(txtNum3.Text);
int d = int.Parse(txtNum4.Text);

int product = a * b * c * d;

lblResult.Text = product.ToString();
}


✔ This code runs when the button is clicked.

🟦 STEP 5 — How the Code Works (Explanation)
1. User enters numbers

User types 4 integer values in textboxes:

txtNum1

txtNum2

txtNum3

txtNum4

2. Button is clicked

btnCalculate_Click method gets executed.

3. Text from input boxes is read
int.Parse(txtNum1.Text)


Converts textbox text → integer.

4. Product is calculated
int product = a * b * c * d;

5. Output is shown
lblResult.Text = product.ToString();


Label shows result on screen.

🟦 STEP 6 — Run the Application

Press F5 or click Start

Browser will open

Enter four numbers

Click Calculate Product

You will see the result