浅谈c#表达式树Expression简单类型比较demo

实例如下：

using system;
using system.linq.expressions;

class dynamicpredicate
{
  public static expression<func<t, t, bool>> generate<t>(string op)
  {
    parameterexpression x = expression.parameter(typeof(t), "x");
    parameterexpression y = expression.parameter(typeof(t), "y");
    return expression.lambda<func<t, t, bool>>
    (
      (op.equals(">")) ? expression.greaterthan(x, y) :
        (op.equals("<")) ? expression.lessthan(x, y) :
          (op.equals(">=")) ? expression.greaterthanorequal(x, y) :
            (op.equals("<=")) ? expression.lessthanorequal(x, y) :
              (op.equals("!=")) ? expression.notequal(x, y) :
                expression.equal(x, y),
      x,
      y
    );
  }
}

static void main()
  {
    string op = ">=";
    var integerpredicate = dynamicpredicate.generate<int>(op).compile();
    var floatpredicate = dynamicpredicate.generate<float>(op).compile();

    int ia = 12, ib = 4;
    console.writeline("{0} {1} {2} : {3}",
              ia, op, ib, integerpredicate(ia, ib));

    float fa = 867.0f, fb = 867.0f;
    console.writeline("{0} {1} {2} : {3}",
              fa, op, fb, floatpredicate(fa, fb));

    console.writeline("{0} {1} {2} : {3}",
              fa, ">", fb, dynamicpredicate.generate<float>(">").compile()(fa, fb));

    console.readline();
  }

以上这篇浅谈c#表达式树expression简单类型比较demo就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。