Checkboxes with Repeaters and DataGrids

[Fresh Air Rider]

I am having trouble getting checkboxes to work within Repeaters and
DataGrids

I have tried to access the value of each checkbox within a repeater
which has been ticked as follows :-

string sValues ="values";
foreach (RepeaterItem ri in rptrPublications.Items){
CheckBox cbx = (CheckBox)ri.FindControl("cbxPub");
if(cbx.Checked){
sValues = sValues + cbx.Checked.ToString();
}
}
Response.Write(sValues);

For some reason, it doesn't recognise the cbx.Checked statement, but
if I remove this line, it happily writes out the values of each
checkbox.

I am also having getting a checkbox's OnCheckedChanged event to fire
when it's within either s Repeater or a DataGrid

Could anyone please put forward some suggestions ?

Thanks