preserve emptiness in ColorFormatter

svn path=/trunk/mcs/; revision=55711

mcs/class/System.Web/System.Web.UI/ChangeLog

@@ -1,3 +1,7 @@
+2006-01-18 Konstantin Triger <[email protected]>
+
+	* ObjectStateFormatter.cs: preserve emptiness in ColorFormatter.
+
 2006-01-18 Konstantin Triger <[email protected]>
 
 	* HtmlTextWriter.cs: perform case insensitive compare;

mcs/class/System.Web/System.Web.UI/ObjectStateFormatter.cs

@@ -663,19 +663,24 @@ namespace System.Web.UI {
 				
 				if (!c.IsKnownColor) {
 					w.Write (PrimaryId);
-					w.Write (c.ToArgb ());
+					w.Write(c.IsEmpty);
+					if (!c.IsEmpty)
+						w.Write (c.ToArgb ());
 				} else {
 					w.Write (SecondaryId);
-					w.Write ((int) c.ToKnownColor ());
+					w.Write(c.IsEmpty);
+					if (!c.IsEmpty)
+						w.Write ((int) c.ToKnownColor ());
 				}
 			}
 			
 			protected override object Read (byte token, BinaryReader r, ReaderContext ctx)
 			{
+				bool isEmpty = r.ReadBoolean();
 				if (token == PrimaryId)
-					return Color.FromArgb (r.ReadInt32 ());
+					return isEmpty ? Color.Empty : Color.FromArgb (r.ReadInt32 ());
 				else
-					return Color.FromKnownColor ((KnownColor) r.ReadInt32 ());
+					return isEmpty ? Color.Empty : Color.FromKnownColor ((KnownColor) r.ReadInt32 ());
 			}
 			
 			protected override Type Type {