refactor: massive refactor input elements, step 1/3

src/Shared/HandyControlDemo_Shared/Tools/ValidationRule/NumericUpDownDemoRule.cs

@@ -0,0 +1,19 @@
+using System.Globalization;
+using System.Windows.Controls;
+
+namespace HandyControlDemo.Tools;
+
+public class NumericUpDownDemoRule : ValidationRule
+{
+    public override ValidationResult Validate(object value, CultureInfo cultureInfo)
+    {
+        if (value is not double doubleValue)
+        {
+            return new ValidationResult(false, HandyControl.Properties.Langs.Lang.FormatError);
+        }
+
+        return doubleValue % 2 > double.Epsilon
+            ? new ValidationResult(false, Properties.Langs.Lang.Error)
+            : ValidationResult.ValidResult;
+    }
+}