Add two Button and one Label in your Windows Application Form.

using System;

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

namespace DynamicTexBox
{

public partial class Form2 : Form

{

public Form2()

{

InitializeComponent();

}

TextBox[] textBoxes;


private void button1_Click(object sender, EventArgs e)

{
int value = 3;

textBoxes = new TextBox[value];

for (int i = 1; i < value; i++)

{
textBoxes[i] = new TextBox();

textBoxes[i].SetBounds(30, i * 30, 60, 20);

this.Controls.Add(textBoxes[i]);
}

}

private void button2_Click(object sender, EventArgs e)

{
int myTotal = 0;

foreach (Control ctl in this.Controls)

{

if (ctl.GetType() == typeof(TextBox))

{

myTotal += Convert.ToInt32(ctl.Text);

}

}

label1.Text = myTotal.ToString();
}

}

}