使用准则进行条件查询--1.4.从窗体中选择查询的条件
使用准则进行条件查询--1.4.从窗体中选择查询的条件
4.从窗体中选择查询的条件 前面的方法虽然简单，但对用户来说操作不够方便，对设计者来说也难以控制，如果通过窗体来实现，这些问题就可以解决了。 如下面的窗体，运行时用户可以在组合框中选择要查询司机的姓名，按下查询按钮就可以看到查询的结果。
下面详细地列出设计的步骤：
创建一个窗体，按下控件向导按钮，在窗体上添加一个组合框。在第一个对话框中
选择“我想让组合框在一个表或查询中查找这些值”，下一步。
选择一个为组合框提供数据的表或查询。下一步。
选择组合框中要显示的数据，通常除了选择要显示在组合框中的字段以外，还选择表的主关键字。下一步。
如果主关键字是自动编号字段，通常选择“隐藏主关键字列”，下一步，给组合框起个名，完成。
建一个查询，在查询的字段的准则中输入刚才窗体组合框的字段名，这里输入“[Forms]![条件查询]![要查询的司机]”。为了方便，可以用表达式生成器生成这个表达式。 保存这个查询为“按司机姓名查询”。
再回到刚才的窗体中，添加一个按钮。在控件向导的第一对话框中选择“杂项/运行查询”。下一步。
选择刚建的查询“按司机姓名查询”，下一步。
输入按钮上显示的文本，或者用图片来表示按钮，随你啦。下一步，给按钮起个名，完成。
0 运行这个窗体，就象本页最上面的图中所示，在组合框中选择“马千斤”，按下“查询”按钮，就会看到查询的结果
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