Extension method to get property name

问题:

I have an extension method to get property name as

public static string Name<T>(this Expression<Func<T>> expression)
{
    MemberExpression body = (MemberExpression)expression.Body;
    return body.Member.Name;
}

I am calling it as

string Name = ((Expression<Func<DateTime>>)(() => this.PublishDateTime)).Name();

This is working fine and returns me PublishDateTime as string.

However I have an issue with the calling statement, it is looking too complex and I want some thing like this.

this.PublishDateTime.Name()

Can some one modify my extension method?

回答1:

Try this:

public static string Name<T,TProp>(this T o, Expression<Func<T,TProp>> propertySelector)
{
    MemberExpression body = (MemberExpression)propertySelector.Body;
    return body.Member.Name;
}

The usage is:

this.Name(x=>x.PublishDateTime);

回答2:

With C# 6.0, you can use:

nameof(PublishDateTime)

回答3:

You can't do this.PublishDateTime.Name(), as the only thing that will be passed into the extension method is the value or reference on which you call the extension method.

Whether it's a property, field, local variable or method result doesn't matter, it won't have a name that you can access inside the extension method.

The expression will be "verbose", see How can I add this method as an extension method to properties of my class? (thanks @Black0ut) to put it in a static helper class.