如何声明具有匿名类型的字段（C＃）

In the code below,how do I declare myLine as a public(global) variable? The problem is that I can't use the keyword "var".

在下面的代码中,如何将myLine声明为公共(全局)变量?问题是我不能使用关键字“var”。

    public static IEnumerable<string> ReadLines(StreamReader reader)
    {
        while (!reader.EndOfStream)
        {
            yield return reader.ReadLine();
        }
    }

    private void Filter1(string filename)
    {
        using(var writer = File.CreateText(Application.StartupPath + "\\temp\\test.txt"))
        {
            using (var reader = File.OpenText(filename))
            {
                int[] Ids = { 14652, 14653, 14654, 14655, 14656, 14657, 14658, 14659, 14660 };
                var myLine = from line in ReadLines(reader)
                             where line.Length > 1
                             let id = int.Parse(line.Split('\t')[1])
                             where Ids.Contains(id)
                             let m = Regex.Match(line, @"^\d+\t(\d+)\t.+?\t(item\\[^\t]+\.ddj)")
                             where m.Success == true
                             select new { Text = line, ItemId = id, Path = m.Groups[2].Value };


                foreach (var id in myLine)
                {
                    writer.WriteLine("Item Id = " + id.ItemId);
                    writer.WriteLine("Path = " + id.Path);
                    writer.WriteLine("\n");
                }

            }
        }
    }

I want to do it ,because I have to find a way to gain access to that ienumerable for later use.

我想这样做,因为我必须找到一种方法来获取对该数量的访问以供以后使用。

2 个解决方案

#1

The trouble is that it's using an anonymous type, which you can't use in a field declaration.

麻烦的是它使用的是匿名类型,你不能在字段声明中使用它。

The fix is to write a named type with the same members, and use that type in your query. If you want it to have the same behaviour as your anonymous type, it should:

修复方法是编写具有相同成员的命名类型,并在查询中使用该类型。如果您希望它与您的匿名类型具有相同的行为,它应该:

Take all the values in the constructor

获取构造函数中的所有值

Be immutable, exposing read-only properties

是不可变的,暴露只读属性

Override Equals, GetHashCode and ToString

覆盖Equals,GetHashCode和ToString

Be sealed

You could just use Reflector to decompile the code, but then you'd end up with a generic type which you don't really need.

你可以使用Reflector来反编译代码,但是你最终会得到一个你并不真正需要的泛型类型。

The class would look something like:

该类看起来像:

public sealed class Foo
{
    private readonly string text;
    private readonly int itemId;
    private readonly string path;

    public Foo(string text, int itemId, string path)
    {
        this.text = text;
        this.itemId = itemId;
        this.path = path;
    }

    public string Text
    {
        get { return text; }
    }

    public int ItemId
    {
        get { return itemId; }
    }

    public string Path
    {
        get { return path; }
    }

    public override bool Equals(object other)
    {
        Foo otherFoo = other as Foo;
        if (otherFoo == null)
        {
            return false;
        }
        return EqualityComparer<string>.Default.Equals(text, otherFoo.text) &&
        return EqualityComparer<int>.Default.Equals(itemId, otherFoo.itemId) &&
        return EqualityComparer<string>.Default.Equals(path, otherFoo.path);
    }

    public override string ToString()
    {
        return string.Format("{{ Text={0}, ItemId={1}, Path={2} }}",
                             text, itemId, path);
    }

    public override int GetHashCode()
    {
        int hash = 17;
        hash = hash * 23 + EqualityComparer<string>.Default.GetHashCode(text);
        hash = hash * 23 + EqualityComparer<int>.Default.GetHashCode(itemId);
        hash = hash * 23 + EqualityComparer<string>.Default.GetHashCode(path);
        return hash;
    }
}

Your query would just change at the end to:

您的查询最终会更改为:

select new Foo(line, id, m.Groups[2].Value)

#2

Instead of using an anonymous class with the new keyboard, define a class explicitly with a Text, ItemId, etc. Then the type would be IQueryable<MyClass>. Use that instead of the var keyword.

不使用带有新键盘的匿名类,而是使用Text,ItemId等显式定义类。然后类型将是IQueryable 。使用它而不是var关键字。

#1