When you add a label to the DataGrid, you assign a value to the label

1: You can directly in the design page to the label text bound to the field you want
2: You can find the label inside the ItemDataBound E.item.findcontrol
and assign it a value.
protected void Datagrid1_itemdatabound (Object Sender,system.web.ui.webcontrols.datagriditemeventargs e)
{

if (e.item.itemtype==listitemtype.item| | E.item.itemtype==listitemtype.alternatingitem)
{

String MessageID = (string) e.item.cells[0]. Text;
Label Lab = (label) E.item.findcontrol ("Label1");
Lab. Text= "...";


}

}

foreach (DataGridItem item in this. Datagrid1.items)
{
String strpiece= (TextBox) item. FindControl ("Edit_piece")). Text.trim (). ToString ();
TextBox TextBox1 = Item. FindControl ("TextBox1");
textbox1.text= Convert.ToInt32 (strpiece) *33;
}