GridView用DataItem得到某字段的值、DropDownList通过显示字符选中值

if(e.Row.RowState == DataControlRowState.Edit)
    {
      // Preselect the DropDownList control with the state value
      // for the current row.

      // Retrieve the underlying data item. In this example
      // the underlying data item is a DataRowView object.
      DataRowView rowView = (DataRowView)e.Row.DataItem;

      // Retrieve the state value for the current row.
      String state = rowView["state"].ToString();

      // Retrieve the DropDownList control from the current row.
      DropDownList list = (DropDownList)e.Row.FindControl("StatesList");

      // Find the ListItem object in the DropDownList control with the
      // state value and select the item.
      ListItem item = list.Items.FindByText(state);
      list.SelectedIndex = list.Items.IndexOf(item);
    }