Errors in Apps Checking Prime Number

Question

 This is how my program looks like, sorry for bad arrangement

I get this error: Cannot implicity convert type "string" to "int"

Anyone knows how to fix it? Your help'll be very appriciated

 

 

namespace IsThisPrime

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

int x = textBox1.Text;

int i = 0;

bool Flag = false;

for (i = 2; i <= x / 2; i++)

{

if ((i == x))

i = i + 1;

if ((x % i == 0))

{

Flag = true;

break;

}

}

if ((Flag == false))

{

// this num is prime number

MessageBox.Show("PRIME");

}

else

{

// this num is not prime number

MessageBox.Show("NOT PRIME");

}