The built-in error template in WPF is quite basic: a red rectangle around the control that is in error, and I invariably replace it with something a little fancier. I’m not sure who originated this style of error/validation template, but I know it best from the Visual Studio add-in Resharper.
Using an error icon such as this one from openclipart.org and a fairly simple error template we can create a similar effect of our own that works for multiple control types, and comes complete with a data-bound tool-tip to display the appropriate error message.
Like all my recent WPF samples the source-code for this is included in the learnwpf samples project hosted on bitbucket.
b1cd2c24-a4d0-4099-9404-96d975ef94e0|2|5.0