handling offline and inassisable db in oe (#369)

* handling offline and inassisable db in oe

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/Nodes/ChildFactory.cs

@@ -37,6 +37,11 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.Nodes
         /// </summary>
         public abstract IEnumerable<NodeFilter> Filters { get; }
 
+        /// <summary>
+        /// The list of properties to be loaded with the object
+        /// </summary>
+        public abstract IEnumerable<NodeSmoProperty> SmoProperties { get; }
+
         /// <summary>
         /// Returns the node sub type if the object can have sub types otehr wise returns empty string
         /// </summary>

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/Nodes/NodeSmoProperty.cs

@@ -0,0 +1,23 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+
+namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.Nodes
+{
+    /// <summary>
+    /// Has information for SMO object properties to be loaded with the SMO object
+    /// </summary>
+    public class NodeSmoProperty
+    {
+        /// <summary>
+        /// Property name
+        /// </summary>
+        public string Name { get; set; }
+        /// <summary>
+        /// Indicates which platforms a filter is valid for
+        /// </summary>
+        public ValidForFlag ValidFor { get; set; }
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/Nodes/TreeNode.cs

@@ -286,7 +286,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.Nodes
             return Parent as T;
         }
 
-        protected void PopulateChildren(bool refresh, string name = null)
+        protected virtual void PopulateChildren(bool refresh, string name = null)
         {
             Logger.Write(LogLevel.Verbose, string.Format(CultureInfo.InvariantCulture, "Populating oe node :{0}", this.GetNodePath()));
             Debug.Assert(IsAlwaysLeaf == false);
@@ -331,7 +331,7 @@ namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.Nodes
                     }
                 }
             }
-            catch(Exception ex)
+            catch (Exception ex)
             {
                 string error = string.Format(CultureInfo.InvariantCulture, "Failed populating oe children. error:{0} inner:{1} stacktrace:{2}",
                     ex.Message, ex.InnerException != null ? ex.InnerException.Message : "", ex.StackTrace);