Delphi Try Except 实例

//判断单位转换率
  try
    um_rate := vp_mstr.F(‘vp_um_rate_d‘).AsFloat / vp_mstr.F(‘vp_um_rate_m‘).AsFloat;
    if um_rate <= 0 then
      abort
    else if (vp_mstr.F(‘vp_um‘).AsString = vp_mstr.F(‘part_um‘).AsString) and (um_rate <> 1) then
      abort
    else if (vp_mstr.F(‘vp_um‘).AsString <> vp_mstr.F(‘part_um‘).AsString) and (um_rate = 1) then
      abort;
  except on e:Exception do
    begin
    Application.MessageBox(PChar(E.Message), ‘error‘, 16);//抛出异常信息
    priMsg.ShowMsg(‘004‘);  //004=单位转换率设置错误!
    edt_vp_um_rate_d.SetFocus;
    abort;
    end;
  end;