The WPF application I am working on at the moment contains a questionnaire definition system; the user interface for which contains a number of ComboBoxes (drop-down lists). The nature of the application means that some of these ComboBoxes contain a large number of dynamic entries (not hardcoded, they change based on user actions).

I have found that WPF ComboBoxes with a large number of entries; particularly ones which have overridden ToString methods, can take a second or two to ‘drop down’ (display). This is because WPF renders the entire dropdown interface when it opens; this means if you have many entries in the list each one will be rendered regardless of its position in the list. If you have custom logic inside the ToString methods this can present a significant overhead on the UI thread.

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Ok, so I may have gone overboard on the dot dev domains, obviously, I purchased melodious.dev and forwarded it to this website but I also purchased two random domains:

• itworksonmymachine.dev
• i-am-a-great.dev (in response to spotting @CydeWeys buying i-am-a.dev whilst I was searching twitter for #dotdev)

I could have just forwarded these domains to melodiouscode.net, but on my lunch break, I decided to chuck some single page sites at them for giggles. I, however, did not want to spend any more money than I already do on domain-related things. In steps Cloudflare workers.

For those that do not know about workers; they are small chunks of javascript that you can run on the “edge” of Cloudflare. This means that you can execute code at the moment that a page is requested from your site. In the case of my serverless approach, the code executes before the page request has the chance to realise there is no web server!

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The project I am currently working on is a sizable line-of-business desktop program written using the WPF framework; a framework I particularly like working with due to its extensibility and ease of design (via XAML).
One of the powerful parts of WPF is the ICommand system for binding buttons to ViewModel methods; I won’t go into the details of it here as it deserves an article of its own. However one of its basic functions is the ability to pass a parameter from the UI back to the ViewModel’s ICommand property, such as the selected item in a data table.

The application I am currently working on has lots of nested UI components, and some of the button events need to pass back multiple parameters (something I had not done before). It seems that it is perfectly possible to pass more than one parameter from the XAML View up to the ViewModel.
The XAML is simple, you nest a MultiValueConverter inside your buttons CommandParameter element; you also need to provide a reference to an IMultiValueConverter (which you can define statically in a resource elsewhere in your application).

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I have been asked the question “Can you pass an enumerable to a procedure?” or “How do you pass a table to a stored procedure” several times in the past. The simple answer is “yes”, the slightly more complex answer is “yes, and this is how”!

How to pass an Enumerable to a SQL Stored Procedure in .NET

Although my example code here is in C# the same process applies to other .NET languages.
You can indeed pass an enumerable object to your Stored Procedure by using a special type of SQL object called a “User Defined Table Type”. UDTTs can be used to create tempory tables in a SQL Query without the need to fully write out the TABLE statement; in much the same way they can be used to pass a tempory table to a stored procedure. The only restriction is that the parameter passed into the query must be marked as read-only.
An example SQL statement to create a User Defined Table Type is as follows:

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