I'me giving an example code using this you can control property on any control in Gridview in Templated Field
protected void loadcontrols()
{
for (int i = 0; i < gvReply.Rows.Count; i++)
{
Button btnDelete = gvReply.Rows[i].FindControl("btnDelete") as Button;
HiddenField hf=gvReply.Rows[i].FindControl("hfID") as HiddenField;
if (Session["userid"].ToString() == hf.Value)
{
btnDelete.Visible = true;
}
}
}
it is the example of a Button control , instead you can control the property of checkbox also.