基本上我正在尝试将两个lambdas与Expression类相乘,但我甚至无法构建并且无法找到相关文档。这是我的代码:
var f = x=>x+2;
var g = x=>x+3;
var argX = Expression.Parameter(typeof(double), "x");
var fg = Expression.Multiply(Expression.Constant(g, typeof(Func<double, double>)), Expression.Constant(f, typeof(Func<double, double>)));
//var fg = Expression.Multiply(Expression.Constant(g),Expression.Constant(f));
var lambda = Expression.Lambda<Func<double, double>>(f3, argX);
return lambda.Compile();
答案 0 :(得分:4)
你想要这样的东西:
-lxyz
如果我这样称呼它:
Expression<Func<double,double>> f = x => x + 2;
Expression<Func<double,double>> g = x => x + 3;
var param = Expression.Parameter(typeof(double));
var invokeF = Expression.Invoke(f, param);
var invokeG = Expression.Invoke(g, param);
var mult = Expression.Multiply(invokeF,invokeG);
var lambda = ((Expression<Func<double, double>>)Expression.Lambda(mult, param)).Compile();
我得到30作为有效答案。
答案 1 :(得分:0)
为此,只需将f
和g
定义为Expression
:
var argX = Expression.Parameter(typeof(double), "x");
var f = Expression.Add(argX, Expression.Constant(3.0)); // applies to x => x + 3
var g = Expression.Add(argX, Expression.Constant(2.0)); // applies to x => x + 2
var fg = Expression.Multiply(f, g); // applies to f(x) * g(x)
var lambda = Expression.Lambda<Func<double, double>>(fg, argX);
现在这样称呼:
var r = lambda.Compile()(1);
返回12
。