For my program, Crunch, I'm trying to create a program that will be easy to convert between WPF and Silverlight. While they're the same for the most part, the two have a few differences that can lead to annoying compatibility issues. One of these is WPF's lack of Silverlight's ChildWindow class. The ChildWindow class allows for modal dialogs to pop up inside the Silverlight application itself, removing the need from breaking out of the web browser and showing a window.

Sadly, WPF doesn't have this feature. I've been able to work around this by making my own ModalDialog class. I'm not going into details on that, but one aspect that was annoying me recently.

When a ModalDialog instance displays inside its owning Window, the Window displays a container grid to cover up everything underneath. This works great for preventing mouse access of underlying controls and changing focus while the dialog is open, but this does nothing for keyboard navigation. A user could still hit tab and tab out of the control, leading to any number of problems!

The first thing I tried was disabling all underlying controls. This worked, but it seemed hacky and made the layout pretty ugly.

After some searching, I found there's two simple lines of code I can use to get around this issue. With these two properties set, keyboard focus is trapped within the container until either the property is changed, or another control is forcibly focused through code.

(Locks the tab key to the focused control)

KeyboardNavigation.SetTabNavigation(modalContainerGrid, KeyboardNavigationMode.Cycle)

(Locks the tab key to the focused control if the user's also holding down Ctrl)

KeyboardNavigation.SetControlTabNavigation(modalContainerGrid, KeyboardNavigationMode.Cycle)

I hope this helps someone in the future!

You learn something new every day!

It appears that ASP.Net's TextBox class doesn't have any built-in validation for trimming the Text property's length if the MaxLength property is set to a value greater than zero.

I suppose this is to give user's more leeway in how they want to validate the control, but it's not immediately obvious that a user can get around this limitation just by altering the html! ie: A user could use the FireFox FireBug extension to remove the textbox input's maxlength attribute and load it up with as much text as they'd like!

So remember kids: Always validate your input!

I'd been trying to get around the need to install SQL Compact for users that don't have it already. I'd read everything on msdn about how to do it, but my brain was just not comprehending the stupid easiness of it.

I had been trying to reference the private SQL Compact dlls in my project, thinking I was required to do that to get the private dlls to install. I'm an idiiot, and realized just now that I just need to copy the private dlls with the installer and continue to reference the regular dlls in my project.

*palm-forehead*

Crunch, my diet and exercise tracking software, is coming along nicely! I think a public beta is in the near future.