Odtnhj

I am trying to create a custom IExpressionEditor. In order to new one up I need a WorkflowDesigner, All I have is the ModelItem representing my custom activity. Is it possible to access the WorkflowDesigner from a given ModelItem?

 List<ModelItem> variables = new List<ModelItem>();
 List<ModelItem> nameSpaces = new List<ModelItem>();

 // get the activity from the datacontext
 CustomActivityDesigner cad = this.DataContext as CustomActivityDesigner;
 // try to get the variables
 // look for variables collection cant seem to find them
 ModelProperty mp = cad.ModelItem.Properties["Variables"];

 if(mp != null && mp.PropertyType == typeof(Collection<Variable>))
 
 mp.Collection.ToList().ForEach(i => variables.Add(i));
 

 // get name spaces
 ModelProperty mp2 = cad.ModelItem.Properties["NameSpaces"];

 if(mp2 != null && mp2.PropertyType == typeof(Collection<NameSpace>))
 
 mp2.Collection.ToList().ForEach(i => nameSpaces.Add(i));
 

 // finally need the WorkflowDesigner object
 WorkflowDesigner designer = Modelitem.Root....??? as WorkflowDesigner

 // now we have what we need we can create the IExpressionEditor
 CustomExpressionEditior ce = new CustomExpressionEditior(designer, variables, nameSpaces)

Following the Using a Custom Expression Editor as reference, it seems you should be able to create a Custom Expression Service (which will be creating the Expression Editor instances) and register it to the Services collection on the WorkflowDesigner.

Once it's registered in the WorkflowDesigner's Services collection, you'll be able to:

• Get the editing context for the ModelItem by using ModelItemExtensions.GetEditingContext
  


• Access the Services property of the returned EditingContext
  


• Retrieve the Custom Expression Service you registered on the WorkflowDesginer
  

Hope it helps!