fix(controls): Re-round NumberBox Value on MaxDecimalPlaces change (#1738)

Author: Bintel

src/Wpf.Ui/Controls/NumberBox/NumberBox.cs

@@ -56,7 +56,7 @@ public partial class NumberBox : Wpf.Ui.Controls.TextBox
         nameof(MaxDecimalPlaces),
         typeof(int),
         typeof(NumberBox),
-        new PropertyMetadata(6)
+        new PropertyMetadata(6, OnMaxDecimalPlacesChanged)
     );
 
     /// <summary>Identifies the <see cref="SmallChange"/> dependency property.</summary>
@@ -524,6 +524,19 @@ private static void OnNumberFormatterChanged(DependencyObject d, DependencyPrope
         }
     }
 
+    private static void OnMaxDecimalPlacesChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        if (d is not NumberBox numberBox)
+        {
+            return;
+        }
+    
+        if (numberBox.Value is double currentValue)
+        {
+            numberBox.SetCurrentValue(ValueProperty, Math.Round(currentValue, numberBox.MaxDecimalPlaces));
+        }
+    }
+
     private static partial class Debug
     {
         public static partial void InfoWriteLine(string debugLine);