Tag Archives: Lt

How to Create a Custom Editor for a Domain Model Element Property

Sometimes when defining a property for a domain model element you may need to use a complex type that has more than one property or can’t easily be displayed using a single text field or drop down in the property editor. A good example might be a class that holds a list of strings for a GUI interface or a Rich Text editor for a custom text field required by your framework.


To resolve this you can create a custom editor and hook it into your domain model that will provide a proper user interface to specify information for your property.


There are three steps you need to take in order to wire your domain property to display a custom editor:


1. Create a class derived from System.Drawing.Design.UITypeEditor that will launch the custom dialog box as below:


   2: using System;
   3: using System.Collections.Generic;
   4: using System.Text;
   6: // Need to add a reference to System.Drawing DLL.
   7: using System.Drawing.Design;
   8: using System.Security.Permissions;
   9: using Microsoft.VisualStudio.Modeling;
  10: using Microsoft.VisualStudio.Modeling.Design;
  12: namespace XXX.UIProcessDesigner.UIEditors
  13: {
  15:     // FxCop rule: must have same security demands as parent class
  16:     [PermissionSet(SecurityAction.LinkDemand, Name = "FullTrust"),
  17:         PermissionSet(SecurityAction.InheritanceDemand, Name = "FullTrust")]
  18:     public class FormPromptUITypeEditor : System.Drawing.Design.UITypeEditor
  19:     {
  21:         /// <summary>
  22:         /// Overridden to specify that our editor is a modal form
  23:         /// </summary>
  24:         /// <param name="context"></param>
  25:         /// <returns></returns>
  26:         public override UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
  27:         {
  28:             return UITypeEditorEditStyle.Modal;
  29:         }
  32:         /// <summary>
  33:         /// Called by VS whenever the user clicks on the ellipsis in the 
  34:         /// properties window for a property to which this editor is linked.
  35:         /// </summary>
  36:         /// <param name="context"></param>
  37:         /// <param name="provider"></param>
  38:         /// <param name="value"></param>
  39:         /// <returns></returns>
  40:         public override object EditValue(
  41:             System.ComponentModel.ITypeDescriptorContext context,
  42:             IServiceProvider provider,
  43:             object value)
  44:         {
  46:             // Get a reference to the underlying property element
  47:             ElementPropertyDescriptor descriptor = context.PropertyDescriptor as ElementPropertyDescriptor;
  48:             ModelElement underlyingModelElent = descriptor.ModelElement;
  50:             // context.Instance also returns a model element, but this will either
  51:             // be the shape representing the underlying element (if you selected
  52:             // the element via the design surface), or the underlying element 
  53:             // itself (if you selected the element via the model explorer)
  54:             ModelElement element = context.Instance as ModelElement;
  56:             FormPromptUITypeEditorForm theForm = new FormPromptUITypeEditorForm();
  58:             theForm.Value = (string)value;
  60:             if (theForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
  61:             {
  62:                 value = theForm.Value;
  63:             }
  65:             return value;
  66:         }
  68:     }
  70: }


2. Create a Windows Form dialog that will be displayed when the editor is invoked, such as the one below:




3. Set the Custom Attributes for the Domain Property to reference the UITypeEditor class you have created.


The text is as follows: [System.ComponentModel.Editor(typeof(XXX.UIProcessDesigner.UIEditors.FormActionTypeUITypeEditor),typeof(System.Drawing.Design.UITypeEditor))]


The bold faced text is the full namespace of your class that derives from UITypeEditor.




I normally store all code that I add to a DSL Designer in various folders such as; CustomCode, UIEditors, Validators, etc. That way it is easy to find when I am trying to reference it.


Also, you can debug the UITypeEditor and Dialog by setting breakpoints in the code before you start debugging.



Guidance Development Tools

Guidance includes so many different types of documents; Help, How-Tos, FAQs, Checklists, Code Examples, Design Patterns, and Guidelines to name just a few that coming up with a standard way to develop the needed guidance is a hard task to do from scratch. Luckily Microsoft’s patterns & practices group has a tool that can simplify a lot of this for you.


The Microsoft patterns & practice’s Guidance Explorer provides a one stop shop for discovering, developing and publishing high quality development guidance. The project web site is located at http://www.codeplex.com/guidanceExplorer. There you can find the latest release of the tool as well as links to existing guidance examples developed by the team.


The tool includes an editor which provides standardized templates for many of the types of guidance you may want to include in your factory. The editor also includes the ability to add custom data to each guidance item for filtering by Technology, Category, Topic and Rule Type.


How I see this tool being used is pretty simple. As part of the factory development process the guidance developer creates the various guidance items using Guidance Explorer and then exports them to HTML for inclusion into the factory contents. The factory developer then includes links to the files as part of the recipes using the <DocumentationLinks> tag. Now when ever a consumer of the factory invokes a recipe the Guidance Navigator can navigate to the document relating to the action just taken. This could be anything; a checklist of what steps need to be taken in the process; a how-to article on the use of a model just created or even code examples of how to use the library just added to the project.


Another way to apply this tool to factory development is by incorporating the web edition of the tool. It provides a read-only version of the Guidance Explorer that can utilize an on-line store allowing all of your guidance to be in one place. The web edition could be launched in a separate pane within Visual Studio to provide the full guidance library to the factory consumer as they use the factory. They can perform searches for specific topics, filter on a particular category or use the Guidance Navigation pane to browse all of the sections at their leisure.

In my opinion this is a must have tool in any factory developers toolkit, check it out.