add error handling for CrowType not found in group children

diff --git a/src/GraphicObjects/Group.cs b/src/GraphicObjects/Group.cs
index 087cd38d5f0a52ce577a4607f1cd5c741dd5239a..5107ccc5da620484188acfbb706ab857a61c057a 100644 (file)
--- a/src/GraphicObjects/Group.cs
+++ b/src/GraphicObjects/Group.cs
@@ -290,6 +290,8 @@ namespace Crow
                         break;
 
                     Type t = Type.GetType("Crow." + subTree.Name);
+                                       if (t == null)
+                                               throw new Exception ("Crow." + subTree.Name + " type not found");
                     GraphicObject go = (GraphicObject)Activator.CreateInstance(t);
                     (go as IXmlSerializable).ReadXml(subTree);                    
                     addChild(go);