Development With A Dot

Find Control that Caused a Postback

Sometimes there is the need to find the control that caused the postback from outside the event handler. The following code gives you just that:

public static class PageExtensions
{
	public static Control FindFiredControl(this Page page)
	{
		Control control = page;
		Boolean asyncPost = (page.Request.Form [ "__ASYNCPOST" ] == "true");
		String eventTarget = page.Request.Form [ "__EVENTTARGET" ];

		if (page.IsPostBack == true)
		{
			//check if the postback control is not a button
			if (String.IsNullOrEmpty(eventTarget) == false)
			{
				//all naming containers
				String [] parts = eventTarget.Split('$');
	
				foreach (String part in parts)
				{
					//find control on its naming container
					control = control.FindControl(part);
				}
			}
			else
			{
				//search all submitted form keys
				foreach (String key in page.Request.Form.AllKeys.Where(k => Char.IsLetter(k [ 0 ])).ToArray())
				{
					//all naming containers
					String [] parts = key.Split('$');

					//initialize control to page on each iteration
					control = page;

					foreach (String part in parts)
					{
						//find control on its naming container
						if ((part.EndsWith(".x")) || (part.EndsWith(".y")))
						{
							//ImageButton
							control = control.FindControl(part.Substring(0, part.Length - 2));
						}
						else
						{
							//other button type
							control = control.FindControl(part);
						}
					}
	
					if (control is IPostBackEventHandler)
					{
						if (((control is ScriptManager) || (control is ScriptManagerProxy)) && (asyncPost == true))
						{
							//ScriptManager/ScriptManagerProxy themselves never fire postback events
							continue;
						}
						else
						{
							//found firing event
							break;
						}
					}
	
					//clear control for next iteration
					control = null;
				}
			}
		}
	
		return (control);
	}
}

ASP.NET Events

Here is the full list of all events that occur in an ASP.NET application, from the standard modules, to the page, master page, page controls and master page controls.

ASP.NET Dynamic Data NHibernate Provider

My NHibernateDataSource was just a necessary step in order to build an ASP.NET Dynamic Data provider for NHibernate. I am pleased to say that it is now working! Like the NHibernateDataSource, it is only - for now - merely a proof of concept, it needs cleaning up and still misses the association metadata part, which means no links to associated entities, but list, edit, delete and insert are working fine.

If you want to try it, please download it and send me your feedback.

In order to use it, create a Dynamic Data Web Application project and change the name of the context class on the Global.asax.cs file:

model.RegisterContext(new NHibernateDataModelProvider(typeof(MyNHibernateContext)), new ContextConfiguration() { ScaffoldAllTables = true });

Then, on all of the ASPX files under the DynamicData folder, replace the EntityDataSource declaration for the NHibernateDataSource, keeping all of the properties. Add the NHibernateDataSource files to your project and add references to NHibernate and LINQ to NHibernate, from the NHContrib project, and that's it!

NHibernateDataSource

I wrote a NHibernateDataSource, which can be used in ASP.NET web forms applications just like their counterparts EntityDataSource and LinqDataSource.

It requires a LINQ to NHibernate NHibernateContext-derived class which specifies the queryable entities. You can get it from the NHContrib site.

I have used code from Microsoft's LINQ samples, of which I talked about on a previous post, and you can get a precompiled assembly from there.

I have not implemented the InsertParameters, DeleteParameters and UpdateParameters properties, only the WhereParameters, but it shouldn't be too difficult.

Please note that this code is merely a proof of concept, it may have problems, and it is not optimized. If you find anything in it that should be improved, drop me a line. As usual, hope you find it useful!