Add CToT3 function to convert JSON time strings to DateTime with default date part

(cherry picked from commit c409704)

# Conflicts:
#	dotnet/src/dotnetframework/GxClasses/Core/GXUtilsCommon.cs

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Core/GXUtilsCommon.cs

@@ -2872,6 +2872,32 @@ public static GxSimpleCollection<DateTime> CToT2(GxSimpleCollection<string> stCo
 			}
 			return dtCollection;
 		}
+		public static DateTime CToT3(string value)
+		{
+			if (isNullJsonDate(value))
+				return nullDate;
+			else
+			{
+				DateTime timeOnlyDateTime = nullDate;
+				TimeSpan timeSpan;
+				if (TimeSpan.TryParse(value, out timeSpan))
+				{
+					timeOnlyDateTime = DateTime.MinValue.Add(timeSpan);
+				}
+				else if (DateTime.TryParse(value, CultureInfo.InvariantCulture, DateTimeStyles.None, out timeOnlyDateTime))
+				{
+					timeOnlyDateTime = ResetDate(timeOnlyDateTime);
+				}
+				else if (value.StartsWith(GxDateString.NullValue))
+				{
+					value = value.Substring(GxDateString.NullValue.Length);
+					DateTime.TryParse(GxDateString.GregorianDate + value, CultureInfo.InvariantCulture, DateTimeStyles.None, out timeOnlyDateTime);
+
+				}
+
+				return timeOnlyDateTime;
+			}
+		}
 		public static DateTime CToT2(string value, IGxContext context)
 		{
 			if (isNullJsonDate(value))

dotnet/test/DotNetUnitTest/Domain/TimeZoneTest.cs

@@ -287,6 +287,27 @@ public void Year2050Conversion()
 			#endregion
 
 		}
+		[Fact]
+		public void TimeZoneInJsonTime()
+		{
+			DateTime value = DateTimeUtil.CToT3("19:00:00");
+			DateTime expected = DateTime.MinValue.AddHours(19);
+			Assert.Equal(expected, value);
+
+			value = DateTimeUtil.CToT3("19:00:00.000");
+			Assert.Equal(expected, value);
+
+			value = DateTimeUtil.CToT3("1899-12-31T19:00:00.000");
+			Assert.Equal(expected, value);
 
+			value = DateTimeUtil.CToT3("0000-00-00T19:00:00.000");
+			Assert.Equal(expected, value);
+
+			value = DateTimeUtil.CToT3("0001-01-01T19:00:00.000");
+			Assert.Equal(expected, value);
+
+			value = DateTimeUtil.CToT3("2025-04-14T19:00:00.000");
+			Assert.Equal(expected, value);
+		}
 	}
 }