Checkbox gets reset in WPF Datagrid when sorting

I have a WPF application with DataGrid The DataGrid contains 4 columns with a checkbox template column on the first column the problem is when i check some of the checkbox on the items, the checkbox would got reset when开发者_StackOverflow社区 i sort a certain column. For example i check the checkbox on the row 2 it gets unchecked when i sort the datagrid.

been searching for similar case like this for a while but haven't seen one Thanks,

DataGrid has to redraw rows when sorted. When redrawing it accesses the properties for each item in the bound ItemSource. If the checkbox repaints "unchecked" that tells me that it isnot bound or not properly bound or bound one way