How to reset counting?

Question

Hi,

I'm sorry because i don't know where i can post this thread,

I have a form as below

When I input value into textbox No1, this textbox automatic change to read only = true

After I input into tetxbox No2, Q'ty will be change 1/2 until it's become 2/2.

In this time textbox No1 change from read only = true to false and q'ty will be reset to 0 and counting again,

My code is example but it's working not true:

int count = 0;

if ( clause )

{

count++;

txtqty.Text= count.ToString();

}

if ( count ==2)

{

txtNo1.ReadOnly = false;
txtNo1.Clear();
txtNo1.Focus();
txtqty.Text = "0";

So please help me to solve this troule.

Thank you!