Add configuration to set the behavior or add operations on empty dates to the previous one. (#510)

Author: claudiamurialdo

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

@@ -2640,13 +2640,13 @@ public string Time()
 
 		static public DateTime AddMth(DateTime dt, int cantMonths)
 		{
-			if (dt == nullDate && cantMonths < 0)
+			if (dt == nullDate && (cantMonths < 0 || Preferences.IgnoreAddOnEmptyDates))
 				return nullDate;
 			return dt.AddMonths(cantMonths);
 		}
 		static public DateTime AddYr(DateTime dt, int cantYears)
 		{
-			if (dt == nullDate && cantYears < 0)
+			if (dt == nullDate && (cantYears < 0 || Preferences.IgnoreAddOnEmptyDates))
 				return nullDate;
 			return dt.AddYears(cantYears);
         }
@@ -2701,13 +2701,13 @@ static public int DDiff(DateTime dtMinu, DateTime dtSust)
 		}
 		static public DateTime TAdd(DateTime dt, int seconds)
 		{
-			if (dt == nullDate && seconds < 0)
+			if (dt == nullDate && (seconds < 0 || Preferences.IgnoreAddOnEmptyDates))
 				return nullDate;
 			return dt.AddSeconds(seconds);
 		}
 		static public DateTime TAddMs(DateTime dt, double seconds)
 		{
-			if (dt == nullDate && seconds < 0)
+			if (dt == nullDate && (seconds < 0 || Preferences.IgnoreAddOnEmptyDates))
 				return nullDate;
 			if (seconds % 1 == 0)
 				return dt.AddSeconds((int)seconds);
@@ -2716,7 +2716,7 @@ static public DateTime TAddMs(DateTime dt, double seconds)
 		}
 		static public DateTime DAdd(DateTime dt, int days)
 		{
-			if (dt == nullDate && days < 0)
+			if (dt == nullDate && (days < 0 || Preferences.IgnoreAddOnEmptyDates))
 				return nullDate;
 			return dt.AddDays(days);
 		}

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

@@ -727,6 +727,7 @@ public class Preferences
 		static string blobPath;
 		static string blobPathFolderName;
 		static int blankEmptyDates = -1;
+		static int ignoreAddOnEmptyDate = -1;
 		static int setupDB = -1;
 		static HTMLDocType docType = HTMLDocType.UNDEFINED;
 		static int docTypeDTD = -1;
@@ -898,7 +899,29 @@ public static bool Remote
 			}
 
 		}
+		public static bool IgnoreAddOnEmptyDates
+		{
+			get
+			{
+				if (ignoreAddOnEmptyDate == -1)
+				{
+					string val;
+					if (Config.GetValueOf("IGNORE_ADD_ON_EMPTY_DATE", out val) && val == "1")
+					{
+						ignoreAddOnEmptyDate = 1;
+						return true;
+					}
+					else
+					{
+						ignoreAddOnEmptyDate = 0;
+						return false;
+					}
+				}
+				else return (ignoreAddOnEmptyDate == 1);
+			}
 
+		}
+		
 		public static bool BlankEmptyDates
 		{
 			get