This is because RadTreeList needs to rebind on expand/collapse. Rebinding recreates all the items and the controls inside. Hence, any control that gets recreated inside treelist items is in its initial state. This is why your CheckBoxes all default to their non-checked state. To preserve their checked state after databinding, you need to save each CheckBox's Checked property value to some variable on your page and then restore the Checked state after rebinding inside the ItemDataBound
the Telerik team
Thank you for being the most amazing .NET community! Your unfailing support is what helps us charge forward!
We'd appreciate your vote for Telerik in this year's DevProConnections Awards. We are competing in mind-blowing 20 categories and every vote counts! VOTE for Telerik NOW >>