int a = Convert.ToInt32(textBox1.Text);
switch (a)
{
case int n when (n <= 520000):
break;
case int n when (n >= 520000 && n <=1170000 ):
break;
case int n when (n >= 520000 && n<=2350000):
break;
case int n when (n <= 520000):
break;
case int n when (n <= 520000):
break;
default:
break;
}