LabelExpression.Update(LabelTarget, Expression) 方法
定义
创建一个新的表达式,它类似于此表达式,但使用所提供的子级。Creates a new expression that is like this one, but using the supplied children. 如果所有子级均相同,它将返回此表达式。If all of the children are the same, it will return this expression.
public:
System::Linq::Expressions::LabelExpression ^ Update(System::Linq::Expressions::LabelTarget ^ target, System::Linq::Expressions::Expression ^ defaultValue);
public System.Linq.Expressions.LabelExpression Update (System.Linq.Expressions.LabelTarget target, System.Linq.Expressions.Expression defaultValue);
public System.Linq.Expressions.LabelExpression Update (System.Linq.Expressions.LabelTarget target, System.Linq.Expressions.Expression? defaultValue);
member this.Update : System.Linq.Expressions.LabelTarget * System.Linq.Expressions.Expression -> System.Linq.Expressions.LabelExpression
Public Function Update (target As LabelTarget, defaultValue As Expression) As LabelExpression
参数
- target
- LabelTarget
- defaultValue
- Expression
结果的 DefaultValue 属性The DefaultValue property of the result
返回
如果子级未更改,则为此表达式;否则为具有已更新子级的表达式。This expression if no children are changed or an expression with the updated children.