Is it possible to make a textbox autocomplete in WPF?
I found a sample where a combo box is used and the triangle is removed by editing the style template.
Is there a better solution?
You can find one in the WPF Toolkit, which is also available via NuGet.
This article demos how to create a textbox which can auto-suggest items at runtime based on input, in this case, disk drive folders. WPF AutoComplete Folder TextBox
Also take a look at this nice Reusable WPF Autocomplete TextBox, it was for me very usable.