Property Editors: DateTimeWithTimeZone - Changing timezone mode to Local shows invalid time zone error

src/Umbraco.Infrastructure/PropertyEditors/ValueConverters/DateOnlyValueConverter.cs

@@ -30,5 +30,5 @@ public override bool IsConverter(IPublishedPropertyType propertyType)
 
     /// <inheritdoc/>
     protected override object ConvertToObject(DateTimeDto dateTimeDto)
-        => DateOnly.FromDateTime(dateTimeDto.Date.UtcDateTime);
+        => DateOnly.FromDateTime(dateTimeDto.Date.DateTime);
 }

src/Umbraco.Infrastructure/PropertyEditors/ValueConverters/DateTimeUnspecifiedValueConverter.cs

@@ -30,6 +30,5 @@ public override bool IsConverter(IPublishedPropertyType propertyType)
 
     /// <inheritdoc/>
     protected override object ConvertToObject(DateTimeDto dateTimeDto)
-        => DateTime.SpecifyKind(dateTimeDto.Date.UtcDateTime, DateTimeKind.Unspecified);
-
+        => DateTime.SpecifyKind(dateTimeDto.Date.DateTime, DateTimeKind.Unspecified);
 }

src/Umbraco.Infrastructure/PropertyEditors/ValueConverters/TimeOnlyValueConverter.cs

@@ -30,5 +30,5 @@ public override bool IsConverter(IPublishedPropertyType propertyType)
 
     /// <inheritdoc/>
     protected override object ConvertToObject(DateTimeDto dateTimeDto)
-        => TimeOnly.FromDateTime(dateTimeDto.Date.UtcDateTime);
+        => TimeOnly.FromDateTime(dateTimeDto.Date.DateTime);
 }

src/Umbraco.Web.UI.Client/src/packages/property-editors/date-time/property-editor-ui-date-time-picker-base.ts

@@ -19,8 +19,8 @@
 import type { UUIComboboxElement, UUIComboboxEvent } from '@umbraco-cms/backoffice/external/uui';
 
 interface UmbDateTime {
-	date: string | undefined;
-	timeZone: string | undefined;
+	date: string | null;
+	timeZone: string | null;
 }
 
 interface UmbTimeZonePickerOption extends UmbTimeZone {
@@ -34,6 +34,7 @@
 {
 	private _timeZoneOptions: Array<UmbTimeZonePickerOption> = [];
 	private _clientTimeZone: UmbTimeZone | undefined;
+	private _timeZoneMode: UmbTimeZonePickerValue['mode'] | undefined;
 
 	@property({ type: Boolean, reflect: true })
 	readonly = false;
@@ -104,6 +105,7 @@
 			() => {
 				return (
 					this._displayTimeZone &&
+					this._timeZoneMode !== 'local' &&
 					!!this.value?.timeZone &&
 					!this._timeZoneOptions.some((opt) => opt.value === this.value?.timeZone && !opt.invalid)
 				);
@@ -120,8 +122,13 @@
 		if (this._displayTimeZone) {
 			timeZonePickerConfig = config.getValueByAlias<UmbTimeZonePickerValue>('timeZones');
 		}
+
 		this.#setTimeInputStep(timeFormat);
 		this.#prefillValue(timeZonePickerConfig);
+
+		// To ensure the expected value matches the prefilled value, we trigger an update.
+		// If the values match, no change event will be fired.
+		this.#updateValue(this._selectedDate?.toISO({ includeOffset: false }) || '');
 	}
 
 	#prefillValue(timeZonePickerConfig: UmbTimeZonePickerValue | undefined) {
@@ -158,8 +165,8 @@
 	#prefillTimeZones(config: UmbTimeZonePickerValue | undefined, selectedDate: DateTime | undefined) {
 		// Retrieve the time zones from the config
 		this._clientTimeZone = getClientTimeZone();
+		this._timeZoneMode = config?.mode;
 
-		// Retrieve the time zones from the config
 		const dateToCalculateOffset = selectedDate ?? DateTime.now();
 		switch (config?.mode) {
 			case 'all':
@@ -217,9 +224,7 @@
 			if (pickedTimeZone) {
 				this._selectedTimeZone = pickedTimeZone.value;
 				return;
 			}
-		} else if (this.value?.date) {
-			return; // If there is a date but no time zone, we don't preselect anything
 		}
 
 		// Check if we can pre-select the client time zone
@@ -291,7 +296,7 @@
 
 		if (!this._selectedTimeZone) {
 			if (this.value?.date) {
-				this.value = { date: this.value.date, timeZone: undefined };
+				this.value = { date: this.value.date, timeZone: null };
 			} else {
 				this.value = undefined;
 			}
@@ -312,37 +317,58 @@
 
 		// If the date is invalid, we reset the value
 		if (!newDate.isValid) {
+			if (!this.value) {
+				return; // No change
+			}
 			this.value = undefined;
 			this._selectedDate = undefined;
 			this.dispatchEvent(new UmbChangeEvent());
 			return;
 		}
 
 		this._selectedDate = newDate;
-		this.value = {
-			date: this.#getCurrentDateValue(),
-			timeZone: this._selectedTimeZone,
+
+		const timeZoneToStore = this._selectedTimeZone && this._timeZoneMode !== 'local' ? this._selectedTimeZone : 'UTC';
+		const dateToStore = this._selectedTimeZone !== timeZoneToStore ? newDate.setZone(timeZoneToStore) : newDate;
+
+		const newValue = {
+			date: this.#formatDateValue(dateToStore),
+			timeZone: this._timeZoneMode ? timeZoneToStore : null,
 		};
 
+		// Only update the stored data if it has actually changed to avoid firing unnecessary change events
+		const previousValue = this.value;
+		if (previousValue?.date === newValue.date && previousValue?.timeZone === newValue.timeZone) {
+			return;
+		}
+
+		this.value = newValue;
+		this.dispatchEvent(new UmbChangeEvent());
+
 		if (updateOffsets) {
 			this._timeZoneOptions.forEach((opt) => {
 				opt.offset = getTimeZoneOffset(opt.value, newDate);
 			});
 			// Update the time zone options (mostly for the offset)
 			this._filteredTimeZoneOptions = this._timeZoneOptions;
 		}
-		this.dispatchEvent(new UmbChangeEvent());
 	}
 
-	#getCurrentDateValue(): string | undefined {
+	#formatDateValue(date: DateTime): string | null {
+		let formattedDate: string | undefined;
 		switch (this._dateInputType) {
 			case 'date':
-				return this._selectedDate?.toISODate() ?? undefined;
+				formattedDate = date.toFormat('yyyy-MM-dd');
+				break;
 			case 'time':
-				return this._selectedDate?.toISOTime({ includeOffset: false }) ?? undefined;
+				formattedDate = date.toFormat('HH:mm:ss');
+				break;
 			default:
-				return this._selectedDate?.toISO({ includeOffset: !!this._selectedTimeZone }) ?? undefined;
+				formattedDate = date.toFormat(`yyyy-MM-dd'T'HH:mm:ss${this._timeZoneMode ? 'ZZ' : ''}`);
+				break;
 		}
+
+		return formattedDate ?? null;
 	}
 
 	#onTimeZoneSearch(event: UUIComboboxEvent) {

tests/Umbraco.Tests.Integration/Umbraco.Infrastructure/PropertyEditors/DateTimePropertyEditorTests.cs

@@ -41,7 +41,7 @@ protected override void CustomTestSetup(IUmbracoBuilder builder)
         new object[] { Constants.PropertyEditors.Aliases.DateOnly, false, new DateOnly(2025, 1, 22) },
         new object[] { Constants.PropertyEditors.Aliases.TimeOnly, false, new TimeOnly(18, 33, 1) },
         new object[] { Constants.PropertyEditors.Aliases.DateTimeUnspecified, false, new DateTime(2025, 1, 22, 18, 33, 1) },
-        new object[] { Constants.PropertyEditors.Aliases.DateTimeWithTimeZone, true, new DateTimeOffset(2025, 1, 22, 18, 33, 1, TimeSpan.Zero) },
+        new object[] { Constants.PropertyEditors.Aliases.DateTimeWithTimeZone, true, new DateTimeOffset(2025, 1, 22, 18, 33, 1, TimeSpan.FromHours(2)) },
     ];
 
     [TestCaseSource(nameof(_sourceList1))]
@@ -105,7 +105,7 @@ public async Task Returns_Correct_Type_Based_On_Configuration(
                 .WithValue(
                     new JsonObject
                     {
-                        ["date"] = "2025-01-22T18:33:01.0000000+00:00",
+                        ["date"] = "2025-01-22T18:33:01.0000000+02:00",
                         ["timeZone"] = "Europe/Copenhagen",
                     })
                 .Done()

tests/Umbraco.Tests.UnitTests/Umbraco.Core/PropertyEditors/ValueConverters/DateTimeUnspecifiedValueConverterTests.cs

@@ -86,7 +86,7 @@ public void Can_Convert_To_Intermediate_Value(string? input, object? expected)
     private static object[] _dateTimeUnspecifiedConvertToObjectCases =
     [
         new object[] { null, null },
-        new object[] { _convertToObjectInputDate, DateTime.Parse("2025-08-20T17:30:00") },
+        new object[] { _convertToObjectInputDate, DateTime.Parse("2025-08-20T16:30:00") },
     ];
 
     [TestCaseSource(nameof(_dateTimeUnspecifiedConvertToObjectCases))]

tests/Umbraco.Tests.UnitTests/Umbraco.Core/PropertyEditors/ValueConverters/TimeOnlyValueConverterTests.cs

@@ -86,7 +86,7 @@ public void Can_Convert_To_Intermediate_Value(string? input, object? expected)
     private static object[] _timeOnlyConvertToObjectCases =
     [
         new object[] { null, null },
-        new object[] { _convertToObjectInputDate, TimeOnly.Parse("17:30") },
+        new object[] { _convertToObjectInputDate, TimeOnly.Parse("16:30") },
     ];
 
     [TestCaseSource(nameof(_timeOnlyConvertToObjectCases))]