我尝试创建表达式,但失败了。
我想建立类似的东西Expression<Func<typeof(type), bool>> expression = _ => true;
我的尝试:
private static Expression GetTrueExpression(Type type)
{
LabelTarget returnTarget = Expression.Label(typeof(bool));
ParameterExpression parameter = Expression.Parameter(type, "x");
var resultExpression =
Expression.Return(returnTarget, Expression.Constant(true), typeof(bool));
var delegateType = typeof(Func<,>).MakeGenericType(type, typeof(bool));
return Expression.Lambda(delegateType, resultExpression, parameter); ;
}
Usage:
var predicate = Expression.Lambda(GetTrueExpression(typeof(bool))).Compile();
但我收到错误:Cannot jump to undefined label ''
就如此容易:
private static Expression GetTrueExpression(Type type)
{
return Expression.Lambda(Expression.Constant(true), Expression.Parameter(type, "_"));
}
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)