本文整理匯總了C#中System.Linq.Expressions.Expression類的典型用法代碼示例。如果您正苦於以下問題:C# Expression類的具體用法?C# Expression怎麽用?C# Expression使用的例子?那麽, 這裏精選的類代碼示例或許可以為您提供幫助。
Expression類屬於System.Linq.Expressions命名空間,在下文中一共展示了Expression類的1個代碼示例,這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚,您的評價將有助於係統推薦出更棒的C#代碼示例。
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);
輸出:
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