我喜欢元组。它们允许您快速地将相关信息分组在一起，而不必为此编写结构或类。这在重构非常本地化的代码时非常有用。
然而，初始化它们的列表似乎有点多余。
var tupleList = new List<Tuple<int, string>>
{
Tuple.Create( 1, "cow" ),
Tuple.Create( 5, "chickens" ),
Tuple.Create( 1, "airplane" )
};
难道没有更好的办法吗?我希望有一个类似Dictionary初始化式的解决方案。
Dictionary<int, string> students = new Dictionary<int, string>()
{
{ 111, "bleh" },
{ 112, "bloeh" },
{ 113, "blah" }
};
我们不能使用类似的语法吗?
当前回答
var colors = new[]
{
new { value = Color.White, name = "White" },
new { value = Color.Silver, name = "Silver" },
new { value = Color.Gray, name = "Gray" },
new { value = Color.Black, name = "Black" },
new { value = Color.Red, name = "Red" },
new { value = Color.Maroon, name = "Maroon" },
new { value = Color.Yellow, name = "Yellow" },
new { value = Color.Olive, name = "Olive" },
new { value = Color.Lime, name = "Lime" },
new { value = Color.Green, name = "Green" },
new { value = Color.Aqua, name = "Aqua" },
new { value = Color.Teal, name = "Teal" },
new { value = Color.Blue, name = "Blue" },
new { value = Color.Navy, name = "Navy" },
new { value = Color.Pink, name = "Pink" },
new { value = Color.Fuchsia, name = "Fuchsia" },
new { value = Color.Purple, name = "Purple" }
};
foreach (var color in colors)
{
stackLayout.Children.Add(
new Label
{
Text = color.name,
TextColor = color.value,
});
FontSize = Device.GetNamedSize(NamedSize.Large, typeof(Label))
}
this is a Tuple<Color, string>
其他回答
您可以通过每次调用构造函数来实现这一点
var tupleList = new List<Tuple<int, string>>
{
new Tuple<int, string>(1, "cow" ),
new Tuple<int, string>( 5, "chickens" ),
new Tuple<int, string>( 1, "airplane" )
};
是的!这是可能的。
集合初始化式的{}语法适用于任何IEnumerable 类型，它有一个添加方法，参数数量正确。 不用担心在被窝里是怎么工作的，这意味着你可以 简单地从List<T>扩展，添加一个自定义的add方法来初始化您的 T，你完成了!
public class TupleList<T1, T2> : List<Tuple<T1, T2>>
{
public void Add( T1 item, T2 item2 )
{
Add( new Tuple<T1, T2>( item, item2 ) );
}
}
这允许你做以下事情:
var groceryList = new TupleList<int, string>
{
{ 1, "kiwi" },
{ 5, "apples" },
{ 3, "potatoes" },
{ 1, "tomato" }
};
我认为有一个技巧比较简单，但之前没有提到过:
var asdf = new [] {
(Age: 1, Name: "cow"),
(Age: 2, Name: "bird")
}.ToList();
我认为这比:
var asdf = new List<Tuple<int, string>> {
(Age: 1, Name: "cow"),
(Age: 2, Name: "bird")
};
c# 7.0允许你这样做:
var tupleList = new List<(int, string)>
{
(1, "cow"),
(5, "chickens"),
(1, "airplane")
};
如果你不需要List，而只是一个数组，你可以这样做:
var tupleList = new(int, string)[]
{
(1, "cow"),
(5, "chickens"),
(1, "airplane")
};
如果你不喜欢“Item1”和“Item2”，你可以做:
var tupleList = new List<(int Index, string Name)>
{
(1, "cow"),
(5, "chickens"),
(1, "airplane")
};
或者对于数组:
var tupleList = new (int Index, string Name)[]
{
(1, "cow"),
(5, "chickens"),
(1, "airplane")
};
tupleList[0]。索引和tupleList[0]。的名字
框架4.6.2及以下
您必须安装系统。Nuget包管理器中的ValueTuple。
框架4.7及以上
它被内置到框架中。不要安装System.ValueTuple。实际上，将其从bin目录中删除。
注意:在现实生活中，我无法在牛、鸡和飞机之间做出选择。我真的会很纠结。
var colors = new[]
{
new { value = Color.White, name = "White" },
new { value = Color.Silver, name = "Silver" },
new { value = Color.Gray, name = "Gray" },
new { value = Color.Black, name = "Black" },
new { value = Color.Red, name = "Red" },
new { value = Color.Maroon, name = "Maroon" },
new { value = Color.Yellow, name = "Yellow" },
new { value = Color.Olive, name = "Olive" },
new { value = Color.Lime, name = "Lime" },
new { value = Color.Green, name = "Green" },
new { value = Color.Aqua, name = "Aqua" },
new { value = Color.Teal, name = "Teal" },
new { value = Color.Blue, name = "Blue" },
new { value = Color.Navy, name = "Navy" },
new { value = Color.Pink, name = "Pink" },
new { value = Color.Fuchsia, name = "Fuchsia" },
new { value = Color.Purple, name = "Purple" }
};
foreach (var color in colors)
{
stackLayout.Children.Add(
new Label
{
Text = color.name,
TextColor = color.value,
});
FontSize = Device.GetNamedSize(NamedSize.Large, typeof(Label))
}
this is a Tuple<Color, string>
