I have no problem running this code:
var a = "1.1"; var b = Convert.ToSingle(a); Program.Notify("Test Program", a + "<br>" + b);
Convert.ToSingle() works normally.
But there may be the problem when you try to compare
float values, because they may not contain exactly representation of your numbers (see https://stackoverflow.com/questions/7127114/net-floating-point-comparison).
You may use
Math.Abs(x1-x2) < diff where
diff is something like