Switch<T>.Expression 属性

定义

命名空间:

System.Activities.Statements

程序集:

System.Activities.dll

获取要与 Cases 集合中的键进行比较的对象。

public:
 property System::Activities::InArgument<T> ^ Expression { System::Activities::InArgument<T> ^ get(); void set(System::Activities::InArgument<T> ^ value); };

[System.Activities.RequiredArgument]
public System.Activities.InArgument<T> Expression { get; set; }

[<System.Activities.RequiredArgument>]
member this.Expression : System.Activities.InArgument<'T> with get, set

Public Property Expression As InArgument(Of T)

属性值

InArgument<T>

要与 Cases 集合中的键进行比较的对象。

属性

RequiredArgumentAttribute

示例

下面的代码示例演示如何设置 Switch<T> 活动的 Expression 属性。

// check if the number is ok...
new Switch<int>()
{
    DisplayName = "Verify Value from User",
    Expression = ExpressionServices.Convert<int>( env => numberFromUser.Get(env).CompareTo(numberToGuess.Get(env)) ),
    Cases =
    {
        { 0, new Assign<bool>()
            {
                To = new OutArgument<bool>(finished),
                Value = true
            }
        },
        {  1, new WriteLine() { Text = "    Try a lower number number..." } },
        { -1, new WriteLine() { Text = "    Try a higher number" } }
    }
}

注解

在计算表达式之后进行比较。