如题.
解决方案 »
- 有关网页链接显示问题
- 更改了TLB库的GUID后,注册组件报错....
- 大家給點意見,老大為什麼不讓我在SQL 語句裡面加 CASE 條件和運算?
- 请问StringGrid中如何将选中的某些框改颜色,在线等,谢谢
- DELPHI中如何使用SQL的赋值语句.查询结果赋值问题.
- DBgrid 的怎么不能实现这个功能??? 不会是真的吧
- 怎样取消系统默认的菜单快捷键??
- DBComboBox可以做到象ASP的下拉列表一样吗?
- 百合过完年回来了。。。。
- SMTP下的监视程序如何做,还有就是SMTP和POP3的区别?各位高手请指教
- 再次散分~~~~~~~~~~~~~~~~~~~~
- 请问各位仁兄,哪里有Delphi的安装制作程序可以下载?
是用select count(*) from myTable吗??
2.直接用recordcount也可以,比如用query,判断1.recordcount>0
vk_LButton = $01;
vk_RButton = $02;vk_Cancel = $03;vk_MButton = $04; { NOT contiguous with L & RBUTTON }vk_Back = $08;vk_Tab = $09;vk_Clear = $0C;vk_Return = $0D;vk_Shift = $10;vk_Control = $11;vk_Menu = $12;vk_Pause = $13;vk_Capital = $14;vk_Escape = $1B;vk_Space = $20;vk_Prior = $21;vk_Next = $22;vk_End = $23;vk_Home = $24;vk_Left = $25;vk_Up = $26;vk_Right = $27;vk_Down = $28;vk_Select = $29;vk_Print = $2A;vk_Execute = $2B;vk_SnapShot = $2C;vk_Copy = $2C not used by keyboards }vk_Insert = $2D;vk_Delete = $2E;vk_Help = $2F;vk_A thru vk_Z are the same as their ASCII equivalents: 'A' thru 'Z' }vk_0 thru vk_9 are the same as their ASCII equivalents: '0' thru '9' }vk_NumPad0 = $60;vk_NumPad1 = $61;vk_NumPad2 = $62;vk_NumPad3 = $63;vk_NumPad4 = $64;vk_NumPad5 = $65;vk_NumPad6 = $66;vk_NumPad7 = $67;vk_NumPad8 = $68;vk_NumPad9 = $69;vk_Multiply = $6A;vk_Add = $6B;vk_Separator = $6C;vk_Subtract = $6D;vk_Decimal = $6E;vk_Divide = $6F;vk_F1 = $70;vk_F2 = $71;vk_F3 = $72;vk_F4 = $73;vk_F5 = $74;vk_F6 = $75;vk_F7 = $76;vk_F8 = $77;vk_F9 = $78;vk_F10 = $79;vk_F11 = $7A;vk_F12 = $7B;vk_F13 = $7C;vk_F14 = $7D;vk_F15 = $7E;vk_F16 = $7F;vk_F17 = $80;vk_F18 = $81;vk_F19 = $82;vk_F20 = $83;vk_F21 = $84;vk_F22 = $85;vk_F23 = $86;vk_F24 = $87;vk_NumLock = $90;vk_Scroll = $91;
几乎所有的虚键,呵呵
然后单步跟踪,就可以知道enter的符号了
2)是对的,如果返回0则表示空
或者select * from my table where....
如果 query的isempty属性为true则为空
你的那种方法是可行的,也很好
还有就是 query.text:='select * from Table'
query.Open
if query.Eof and query.Bof then
begin
showmessage('数据集为空');
end;
uses Variants;function VarIsNull(const V: Variant): Boolean;
用于判断所有Variant是否为空!
http://expert.csdn.net/Expert/topic/2073/2073178.xml?temp=.2358057
2.判断query1.recordcount=0即为空
2. 在 OnKeyPress 事件中 Enter 的 Key = $0D