When overridden in a derived class , returns the expression string that is formed by the expression editor sheet property values 当在派生类中重写时，返回由表达式编辑器表属性值组成的表达式字符串。
Otherwise , an empty string , if the expression editor does not have an associated expression prefix 派生的类所支持的表达式前缀的字符串；否则，如果表达式编辑器没有关联的表达式前缀，则为空字符串( " ) 。
Returns a resource expression editor sheet that is initialized with the input expression string and service provider implementation 返回使用输入表达式字符串和服务提供程序实现初始化的资源表达式编辑器表。
A property in the properties window . you can open the expression editor by right - clicking a text box or by choosing 可以通过以下方法打开表达式编辑器：右键单击某文本框，或者在某属性的值列表中选择< expression > 。
The expression prefix identifies the custom expression type and associates an expression with the expression builder and expression editor 表达式前缀标识自定义表达式类型，并将表达式与表达式生成器和表达式编辑器关联。
Other important report design enhancements include an updated expression editor , and improved integration with other sql server components 重要的报表设计增强功能还包括更新的表达式编辑器与其他sql server组件的改进的集成。
For example , a custom expression editor sheet class that implements additional expression properties can define the default values for the expression properties in the 例如，实现附加的表达式属性的自定义表达式编辑器表类可在
The expression editor is context - sensitive ; the category items and descriptions change in response to the expression category you are working with 表达式编辑器是上下文相关的；类别项和说明会随着您使用的表达式的类别而变化。
Class to present custom expression editor sheets to the user , and then evaluate the selected expression for design - time rendering . when you browse the 类向用户显示自定义表达式编辑器表，然后再计算选定的表达式以便在设计时呈现。
