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服务器之家。
dy("nrwz");
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