A condition evaluator.
Add-ins may use conditions to register nodes in an extension point which are only visible under some contexts. For example, an add-in registering a custom menu option to the main menu of a sample text editor might want to make that option visible only for some kind of files. To allow add-ins to do this kind of check, the host application needs to define a new condition.
ConditionType Class Documentation
Example #1
0
		public void RegisterCondition (string id, ConditionType type)
		{
			type.Id = id;
			ConditionInfo info = CreateConditionInfo (id);
			ConditionType ot = info.CondType as ConditionType;
			if (ot != null)
				ot.Changed -= new EventHandler (OnConditionChanged);
			info.CondType = type;
			type.Changed += new EventHandler (OnConditionChanged);
		}
Example #2
0
        public override bool Evaluate(ExtensionContext ctx)
        {
            if (!base.Evaluate(ctx))
            {
                return(false);
            }

            ConditionType type = ctx.GetCondition(typeId);

            if (type == null)
            {
                AddinManager.ReportError("Condition '" + typeId + "' not found in current extension context.", null, null, false);
                return(false);
            }

            try {
                return(type.Evaluate(node));
            }
            catch (Exception ex) {
                AddinManager.ReportError("Error while evaluating condition '" + typeId + "'", null, ex, false);
                return(false);
            }
        }
Example #3
0
        void OnConditionChanged(object s, EventArgs a)
        {
            ConditionType cond = (ConditionType)s;

            NotifyConditionChanged(cond);
        }
Example #4
0
		internal void NotifyConditionChanged (ConditionType cond)
		{
			try {
				fireEvents = true;
				
				ConditionInfo info = (ConditionInfo) conditionTypes [cond.Id];
				if (info != null && info.BoundConditions != null) {
					Hashtable parentsToNotify = new Hashtable ();
					foreach (BaseCondition c in info.BoundConditions) {
						ArrayList nodeList = (ArrayList) conditionsToNodes [c];
						if (nodeList != null) {
							foreach (TreeNode node in nodeList)
								parentsToNotify [node.Parent] = null;
						}
					}
					foreach (TreeNode node in parentsToNotify.Keys) {
						if (node.NotifyChildrenChanged ())
							NotifyExtensionsChanged (new ExtensionEventArgs (node.GetPath ()));
					}
				}
			}
			finally {
				fireEvents = false;
			}

			// Notify child contexts
			lock (conditionTypes) {
				if (childContexts != null) {
					foreach (WeakReference wref in childContexts) {
						ExtensionContext ctx = wref.Target as ExtensionContext;
						if (ctx != null)
							ctx.NotifyConditionChanged (cond);
					}
				}
			}
		}