You're barking up the wrong tree. If you want to bind data to the Checked property of a CheckBox then the data has to be type Boolean. You would need to add a new property to the class that you're binding that is type Boolean. For instance, if you have a String property that returns "Y" or "N" you can add a new property that returns whether or not that property value equals "Y". That will return a Boolean: True for "Y" and False for "N". You can then bind that Boolean property to your CheckBox's Checked property.

Also, before you say that you're using a typed DataSet and you can't add properties, the code generated by the Data Source wizard is all partial classes so you absolutely can add your own members to all those classes, simply by declaring another partial class in the same namespace with the same name.