如何将表达式传递给IronPython中的C＃函数

Given a C# function as below, what is the valid syntax in IronPython to call it?

给定C＃函数如下，IronPython中调用它的有效语法是什么？

public void MyFunction( Expression<Action> foo)
{

}

1 个解决方案

#1

You just need to construct an expression that fits the pattern. In the expression library, a generic expression is a specialized lambda expression. So you would just write the appropriate lambda expression in IronPython. Unfortunately you won't get any compiler help with this as you would in C#, you'll have to build it by hand.

您只需要构造一个适合该模式的表达式。在表达式库中，泛型表达式是一个专门的lambda表达式。所以你只需要在IronPython中编写适当的lambda表达式。不幸的是，你不会像在C＃中那样得到任何编译器帮助，你必须手动构建它。

Fortunately, the dlr will be very forgiving and will infer some types for you where possible.

幸运的是，dlr将非常宽容，并会在可能的情况下为您推断某些类型。

Given a library SomeLibrary.dll, with a given class:

给定一个SomeLibrary.dll库，给定一个类：

using System;
using System.Linq.Expressions;

namespace SomeNamespace
{
    public class SomeClass
    {
        public void SomeMethod(Expression<Action> expr) => Console.WriteLine(expr);
    }
}

import clr

clr.AddReference('System.Core')
clr.AddReference('SomeLibrary')

from System import Console, Array, Type, Action
from System.Linq.Expressions import *
from SomeNamespace import SomeClass

# build the expression
expr = Expression.Lambda(
    Expression.Call(
        clr.GetClrType(Console).GetMethod('WriteLine', Array[Type]([str])),
        Expression.Constant('Hello World')
    )
)

# technically, the type of expr is Expression as far as C# is concerned
# but it happens to be an instance of Expression<Action> which the dlr will make work
SomeClass().SomeMethod(expr)

#1