.net Framework 4中的表达式名称 [英] nameof expression in .net framework 4
问题描述
Visual Studio 2015和c#6中引入了
"nameof" expression is introduced in Visual Studio 2015 and c# 6
如何在较旧的版本(如.net Framework 4)中使用它或编写类似的方法?
How can u use it or write a similar method in older versions like .net framework 4.
推荐答案
如果您要在C#6之前谈论C#的等效项,那么这将(以hacky的方式)完成属性的工作.它可能可以扩展为包括字段,方法等.
If you're talking about an equivalent for C# before C#6, this will get the job done (in a hacky way) for properties. It can probably be expanded upon to include fields, methods, etc.
public static class TestExtension
{
public static String nameof<T, TT>(this T obj, Expression<Func<T, TT>> propertyAccessor)
{
if (propertyAccessor.Body.NodeType == ExpressionType.MemberAccess)
{
var memberExpression = propertyAccessor.Body as MemberExpression;
if (memberExpression == null)
return null;
return memberExpression.Member.Name;
}
return null;
}
}
只是快速地进行了说明,因此有很多地方需要改进,但是您可以这样使用它:
Just whipped this up quickly, so there's a lot to be improved, but you use it like this:
public class myClass
{
public string myProp { get; set; }
}
var a = new myClass();
var result = a.nameof(b => b.myProp);
结果包含"myProp"
Result contains 'myProp'
更新:
更全面(尽管仍然不那么漂亮)
More comprehensive (though still not that pretty)
public static class TestExtension
{
public static String nameof<T, TT>(this Expression<Func<T, TT>> accessor)
{
return nameof(accessor.Body);
}
public static String nameof<T>(this Expression<Func<T>> accessor)
{
return nameof(accessor.Body);
}
public static String nameof<T, TT>(this T obj, Expression<Func<T, TT>> propertyAccessor)
{
return nameof(propertyAccessor.Body);
}
private static String nameof(Expression expression)
{
if (expression.NodeType == ExpressionType.MemberAccess)
{
var memberExpression = expression as MemberExpression;
if (memberExpression == null)
return null;
return memberExpression.Member.Name;
}
return null;
}
}
访问静态属性/字段:
TestExtension.nameof(() => myClass.MyOtherField)
访问函数中的参数:
void func (int a) {
TestExtension.nameof(() => a);
}
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