I set the ShowCheckBoxes property of a ListView to true. Now how can I change checkbox state to THREE state instead of two states. I know with a CheckBox you can set IsThreeState = true. I am not able to find this property of the ListView.
Currently, this feature is not supported by RadListView. However, as this sounds like a reasonable functionality, I have logged it to PITS as a feature request and we will implement it in a future release. Here is the link to the PITS item. For the time being, you can enable the ThreeState behavior of RadListView's items by adding a visual style to the indeterminate state of the items in the theme you are using and using the following code to apply it: