Question

I have a WPF Listbox control and I would like to allow the user to change the selected item by using type-ahead. The behavior I’m looking for is exactly like windows explorer. As you continue to type the text of a folder name, the list will keep selecting the more correct item.

For example assume this folder structure:

OtherFolderName
MyFirstFolder
MyFirstFileFolder
MyFirstList

If you select OtherFolderName with the mouse, then start typing MyFirstF the item MyFirstFolder will be selected, but if you continue typing MyFirstFi the item MyFirstFileFolder will be selected.

My WPF Listbox does not exhibit this behavor, I am hoping I can easily enable it, as the old WinForms listbox did just this.

Answer 1

Take a look at the TextSearch class, specifically the TextSearch.TextPath attached property:

<ListBox TextSearch.TextPath="FolderName" ... />

The TextSearch.TextPath property enables text searching and specifies how to extract the search text from each item. In this case I assumed each of your Folder objects has a property named “FolderName”.

If this doesn’t do everything you’re looking for, you’ll probably have to implement your own search, since the TextSearch feature isn’t particularly tweakable. To do this:

1. Handle the TextInput event
2. Compare the time of the current TextInput with the prior TextInput. If close enough together, append to prefix string otherwise set it to the single character typed.
3. Search all Items for the given prefix & if found set SelectedItem.

I would build this as a separate class using an attached property, similar to the built-in TextSearch class.