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C# Expression类代码示例

本文整理汇总了C#中System.Linq.Expressions.Expression的典型用法代码示例。如果您正苦于以下问题:C# Expression类的具体用法?C# Expression怎么用?C# Expression使用的例子?那么恭喜您, 这里精选的类代码示例或许可以为您提供帮助。


Expression类属于System.Linq.Expressions命名空间,在下文中一共展示了Expression类的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C#代码示例。

示例1: typeof

// Add the following directive to your file:
// using System.Linq.Expressions;  

// The block expression allows for executing several expressions sequentually.
// When the block expression is executed,
// it returns the value of the last expression in the sequence.
BlockExpression blockExpr = Expression.Block(
    Expression.Call(
        null,
        typeof(Console).GetMethod("Write", new Type[] { typeof(String) }),
        Expression.Constant("Hello ")
       ),
    Expression.Call(
        null,
        typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
        Expression.Constant("World!")
        ),
    Expression.Constant(42)
);

Console.WriteLine("The result of executing the expression tree:");
// The following statement first creates an expression tree,
// then compiles it, and then executes it.           
var result = Expression.Lambda<Func<int>>(blockExpr).Compile()();

// Print out the expressions from the block expression.
Console.WriteLine("The expressions from the block expression:");
foreach (var expr in blockExpr.Expressions)
    Console.WriteLine(expr.ToString());

// Print out the result of the tree execution.
Console.WriteLine("The return value of the block expression:");
Console.WriteLine(result);
开发者ID:.NET开发者,项目名称:System.Linq.Expressions,代码行数:33,代码来源:Expression

输出:

The result of executing the expression tree:
Hello World!

The expressions from the block expression:
Write("Hello ")
WriteLine("World!")
42

The return value of the block expression:
42


注:本文中的System.Linq.Expressions.Expression类示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。