//gridview遍历如下： 
foreach (GridViewRow row in GridView1.Rows)
{
  CheckBox cb = (CheckBox)row.FindControl("CheckBox2");
  if (cb.Checked == true)
  {
  }
}
//datagrid遍历：
foreach (DataGridItem oItem in ItemsGrid.Items)
{
  CheckBox ck1 = (CheckBox)oItem.FindControl("CheckBox");
  if (ck1.Checked == true)
  {
  }
}
//datalist遍历
foreach (DateListItem dl in DataList1.Items)
{
  CheckBox cb = (CheckBox)dl.FindControl("CheckBoxID ");
  if(cb.checked)
  ......
}

for(int i=0; i <GridView.Rows.Count;i++)
{
   Label lbl = (Label)GridView.Rows[i].FindControl("Label9")；
}

for(int i=0; i < Repeater.Items.Count;i++)
{
  Label lbl = (Label) Repeater.Items[i].FindControl("Label9")；
}

for(int i=0; i < DataList.Items.Count;i++)
{
  Label lbl = (Label) DataList.Items[i].FindControl("Label9")；
}