DevForce Community Forum : DynamicEntity with expression defined on underlying DataColumn http://www.ideablade.com/forum/ This is an XML content feed of; DevForce Community Forum : DevForce Classic : DynamicEntity with expression defined on underlying DataColumn Wed, 15 Apr 2026 01:45:55 -700 Wed, 22 Aug 2007 09:44:49 -700 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 9.69 360 www.ideablade.com/forum/RSS_post_feed.asp?TID=379 DevForce Community Forum http://www.ideablade.com/forum/forum_images/IdeaBlade_logo_tm.png http://www.ideablade.com/forum/ DynamicEntity with expression defined on underlying DataColumn : thanks! http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=964#964 Author: labcede
Subject: 379
Posted: 22-Aug-2007 at 9:44am

thanks!]]> Wed, 22 Aug 2007 09:44:49 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=964#964 DynamicEntity with expression defined on underlying DataColumn : I'm not really sure when... http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=963#963 Author: kimj
Subject: 379
Posted: 22-Aug-2007 at 8:58am

I'm not really sure when the DataColumn expression is evaluated, so there may be other ways to accomplish this, but here's one way.
 
First, be sure to use an EntityList as the data source for the grid and binding manager. 
 
Next, you need to fire a PropertyChanged event for the expression property.  (Since the DynamicEntity derives from Entity, PropertyChanged will automatically be fired for "simple" properties already.)  If you've used something similar to the sample DelegateHolder class in the tutorials, you can take a somewhat inelegant approach and add logic to the Setter method to do this:
 
public void Setter(object pParent, object pValue) {
   DataRow aRow = (DataRow)pParent;
   aRow[mColumnName] = pValue;
 
   // If Qty or Cost changes, then fire event for calculated Total
   if (mColumnName == "Qty" || mColumnName == "Cost")  {
      DynamicEntity ent = pParent as DynamicEntity;
      ent.ForcePropertyChanged(new PropertyChangedEventArgs("Total"));
   }
}
 
Since the sample DelegateHolder is meant to be multi-purpose you'll probably want to do some refactoring to come up with a cleaner design than this.
 
]]> Wed, 22 Aug 2007 08:58:20 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=963#963 DynamicEntity with expression defined on underlying DataColumn : When creating my DataTable for... http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=958#958 Author: labcede
Subject: 379
Posted: 21-Aug-2007 at 2:03pm

When creating my DataTable for the EntityTypeInfo, I have included a DataColumn that has an expression defined (basically the summary of the row values.

This dynamic entity list is bound to a .NET grid using the DataGridViewBindingManager.  I've added ViewDescriptors to the DataGridViewBindingManager (at run-time) so that I can display the data in the associated DataGridView.

After modifying a cell value, I would expect the Total column to be automatically updated.  However, this is not the case.  Only when the cell is in focus (selected by the mouse or 'tabbed into') does the value update.  How do I work around this?
]]> Tue, 21 Aug 2007 14:03:05 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=379&PID=958#958