question

Hi @MohamedRafiN-6400,
What specific project do you want to use, asp.net webform?
Are you trying to add two values to the database?
You are a newbie, I suggest you to check Microsoft's related documentation, there are specific steps on it.
https://docs.microsoft.com/en-us/aspnet/web-forms/overview/presenting-and-managing-data/model-binding/retrieving-data
Best regards,
Lan Huang

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Since you are starting new, I recommend you to go through ASP.Net Razor Pages along with Entity Framework Core to start building.

https://docs.microsoft.com/en-us/aspnet/core/data/ef-rp/intro?view=aspnetcore-6.0&tabs=visual-studio

The following link gives you a walkthrough for the CRUD operations (Create, Read, UPdate and Delete) .

https://docs.microsoft.com/en-us/aspnet/core/data/ef-rp/crud?view=aspnetcore-6.0

Hope this helps

what is the error in this code?

using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FirstConsoleApp
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
try
{
int input1 = Convert.ToInt32(textBox1.Text);
int input2 = Convert.ToInt32(textBox2.Text);
int result = input1 + input2;
MessageBox.Show("Addition result = " + result.ToString());
}
catch (Exception ex)
{

         }

         //int a, b, c;
        // a = textBox1.Text;
        // b = textBox2.Text;
       // c = a + b;
         //textBox5.Text = c;
     }
 }

}

{
int a, b, c;
a = textBox1.Text;
b = textBox2.Text;
c = a + b;
textBox3.Text = c;
}

what is the error in this code sir?

i have converted into string to integer then also it is not working

int a, b, c;
Convert.ToInt32(this.textBox1.Text);
Convert.ToInt32(this.textBox2.Text);
a = textBox1.Text;
b = textBox2.Text;
c = a + b;
textBox3.Text = c;

The syntax is...

 int a, b, c;
 a = Convert.ToInt32(this.textBox1.Text);
 b = Convert.ToInt32(this.textBox2.Text);
 c = a + b;
 textBox3.Text = c.ToString();

Reference documentation.
Convert.ToInt32 Method

I recommend int.TryParse().