Limiting values for SpinButton

[Kubrix]

I want to limit values that user can enter via spinning. Code:

sbNumberOfKilledEnemiesToSpawnHP = new SpinButton
{
Width = 50, Left = 260, Top = 255
};

sbNumberOfKilledEnemiesToSpawnHP.ValueChanged += (s, a) =>
{
if (sbNumberOfKilledEnemiesToSpawnHP.Value < 10) { sbNumberOfKilledEnemiesToSpawnHP.Value = 10; }
if (sbNumberOfKilledEnemiesToSpawnHP.Value > 25) { sbNumberOfKilledEnemiesToSpawnHP.Value = 25; }
}; 

Problem: I cant input value 21. When I clear Text oi shows 10 But when I enter "21" it sets "25'