Clear datagridview checkbox column with button click

if you are wanting to uncheck all the checkboxes then something like this should do it

for each r as DataGridViewRow in datagridview1.rows
   'this next bit depends on the type of object bound to the gridview
r.DataBoundItem

next

sorry submitted by accident

for each r as DataGridViewRow in datagridview1.rows
   'this next bit depends on the type of object bound to the gridview
   r.DataBoundItem.Item("checkboxcolumn") = False  'if bound to a table
   CType(r.DataBoundItem, objectType).propertyname = False 'if bound to a type of object
next

Solar_Flare,

Doesn't seem to work - locks the form up.

I tried:
r.DataBoundItem.SelectedColumns.Item("checkboxcolumn") = False  'if bound to a table

still doesn't work.

Solar_Flare,

That did the trick.

Thanks,

Dave