I want to implement
Expression<Func<int, int, int>> Max = (p1,p2) => p1 > p2 ? p1:p2;
as an expression tree and tried
ParameterExpression LeftEx = Expression.Parameter(typeof(int), "p1");
ParameterExpression RightEx = Expression.Parameter(typeof(int), "p2");
BinaryExpression GroesserAls = Expression.GreaterThan(LeftEx, RightEx);
ConditionalExpression Cond = BinaryExpression.Condition(GroesserAls, LeftEx, RightEx);
Expression main = Cond.Test;
Expression<Func<int, int, bool>> Lam = Expression.Lambda<Func<int, int, bool>>(main,
new ParameterExpression[] { LeftEx, RightEx });
Console.WriteLine(Lam.Compile().Invoke(333, 1200));
With Cond I either get true/false but not the LeftEx or RightEx that Condition should return.
I couldn't find anything in the documentation.
peter
I think you just need:
Expression<Func<int, int, int>> Lam =
Expression.Lambda<Func<int, int, int>>(Cond, // <=== HERE
new ParameterExpression[] { LeftEx, RightEx });
edit - btw - var
is your friend here:
var p1 = Expression.Parameter(typeof(int), "p1");
var p2 = Expression.Parameter(typeof(int), "p2");
var body = Expression.Condition(Expression.GreaterThan(p1, p2), p1, p2);
var lambda = Expression.Lambda<Func<int, int, int>>(body, p1, p2);
var func = lambda.Compile();
Console.WriteLine(func(333,1200));
Console.WriteLine(func(1200,333));