Decimal property editor: Flexibly parse decimal value with different separators (closes #20823) (#20828)

* Flexibly parse decimal value with different separators.

* Applied suggestions from code review.

src/Umbraco.Core/PropertyEditors/DecimalPropertyEditor.cs

@@ -37,7 +37,6 @@ public class DecimalPropertyEditor : DataEditor
     /// <inheritdoc />
     protected override IConfigurationEditor CreateConfigurationEditor() => new DecimalConfigurationEditor();
 
-
     /// <summary>
     /// Defines the value editor for the decimal property editor.
     /// </summary>
@@ -109,7 +108,38 @@ public class DecimalPropertyEditor : DataEditor
 
             /// <inheritdoc/>
             protected override bool TryParsePropertyValue(object? value, out double parsedDecimalValue)
-                => double.TryParse(value?.ToString(), CultureInfo.InvariantCulture, out parsedDecimalValue);
+            {
+                if (value is null)
+                {
+                    parsedDecimalValue = default;
+                    return false;
+                }
+
+                if (value is decimal decimalValue)
+                {
+                    parsedDecimalValue = (double)decimalValue;
+                    return true;
+                }
+
+                if (value is double doubleValue)
+                {
+                    parsedDecimalValue = doubleValue;
+                    return true;
+                }
+
+                if (value is float floatValue)
+                {
+                    parsedDecimalValue = (double)floatValue;
+                    return true;
+                }
+
+                if (value is IFormattable formattableValue)
+                {
+                    return double.TryParse(formattableValue.ToString(null, CultureInfo.InvariantCulture), NumberStyles.Any, CultureInfo.InvariantCulture, out parsedDecimalValue);
+                }
+
+                return double.TryParse(value.ToString(), NumberStyles.Any, CultureInfo.CurrentCulture, out parsedDecimalValue);
+            }
         }
 
         /// <summary>

tests/Umbraco.Tests.UnitTests/Umbraco.Core/PropertyEditors/DecimalPropertyValueEditorTests.cs

@@ -161,7 +161,27 @@ public class DecimalPropertyValueEditorTests
             Assert.AreEqual(1, result.Count());
 
             var validationResult = result.First();
-            Assert.AreEqual(validationResult.ErrorMessage, "validation_outOfRangeMaximum");
+            Assert.AreEqual("validation_outOfRangeMaximum", validationResult.ErrorMessage);
+        }
+    }
+
+    [TestCase(1.8, true)]
+    [TestCase(2.2, false)]
+    [SetCulture("it-IT")] // Uses "," as the decimal separator.
+    public void Validates_Is_Less_Than_Or_Equal_To_Configured_Max_With_Comma_Decimal_Separator(object value, bool expectedSuccess)
+    {
+        var editor = CreateValueEditor(min: 1, max: 2);
+        var result = editor.Validate(value, false, null, PropertyValidationContext.Empty());
+        if (expectedSuccess)
+        {
+            Assert.IsEmpty(result);
+        }
+        else
+        {
+            Assert.AreEqual(1, result.Count());
+
+            var validationResult = result.First();
+            Assert.AreEqual("validation_outOfRangeMaximum", validationResult.ErrorMessage);
         }
     }