Visual Studio Tips & Tricks 1- Re-register the controls in the .designer.cs file (recovering .designer.cs file)

Okay, I suppose all of you know what the .designer.cs file is, but I will shortly explain...

When you add a control to the page (via the markup editor), this control is also registered in the .designer.cs file, so you can have a reference to it in the code behind class (.cs).
So if you have a page Test.aspx, you will have a group of 3 files in it:

1. Test.aspx - this is the markup code, containing HTML and ASP markup, defining the control, css and so on.
2. Test.aspx.designer.cs - the designer file, where all controls are registered as a variables so you can reference them,
3. Test.aspx.cs - the code behind where you add your code. There you can use the controls, referencing them by the ID you gave them in the markup.
What happens behind the scene is that each runat="server" control is registered as a variable in the designer class like this:

protected global::System.Web.UI.WebControls.DetailsView dvMine

I recently did the following mistake - after added a lot of controls, then a lot of code, and a lot of changes to other files, I accidently got the latest version of the designer file (from the source control) of one of my aspx pages. This way I was having the controls markup, but the control registrations were lost. I wasn't able to CTRL + Z until I got my things back as I had already closed / opened the Visual Studio few times.

As a result When I hit F5 to start in debug mode, I got about 20 compilation errors, stating that I am referencing objects that don't exist.
I didn't want to re-register those controls manually in the .designer.cs, neither to delete them in the markup and re-create them (thus registration in the .designer.cs file will be automatically created).

I was wondering what to do, so I finally got the idea. I hit CTRL + K + D (which should reformat your markup) and the missing controls were auto re-created in the .designer.cs file.

Hope this helps someone out there.