DataTable tt = new DataTable();
  for (int i = 0; i < dgvEdit.Columns.Count;i++ )
   {
tt.Columns.Add(dgvEdit.Columns[i].HeaderText);//创建一个与datagridview一样列名的datatable
  } 
if (!dgvEdit.CurrentRow.IsNewRow)
                        {
                            int count = dgvEdit.SelectedRows.Count;//选中行的个数
                            for (int i = count - 1; i >= 0; i--)
                            {
                                string strId = "";
                               tt.Rows.add(dgvEdig.SelectedRows[i]);                             
                            }