为什么元组的物品是只读的？

我正在考虑使用Tuple类来存储我的程序中需要的2个整数信息（StartAddress，EndAddress）。

但是我发现Tuple项目只是ReadOnly，所以如果我需要为一个项目设置一个值，我需要重新实例化一个Tuple。

这个devise决定背后的原因是什么？

Answer 1

元组起源于函数式编程 。 在（纯粹的）函数式编程中， 所有的东西都是不可变的，一个variables只有一个定义，就像math一样。 .NETdevise师在将函数风格整合到C＃/ .NET中时明智地遵循相同的原则，尽pipe它最终成为主要的（混合语言）语言。

注意：虽然我怀疑元组是不可变的，但事实上这并不会让你的任务变得更加困难，但也可能使用匿名types（或者只是一个简单的结构）。

Answer 2

我想知道为什么没有这样的事情。 但是，这是我喜欢使用的。

 namespace System { /// <summary> /// Helper so we can call some tuple methods recursively without knowing the underlying types. /// </summary> internal interface IWTuple { string ToString(StringBuilder sb); int GetHashCode(IEqualityComparer comparer); int Size { get; } } /// <summary> /// Represents a writable 2-tuple, or pair. /// </summary> /// <typeparam name="T1">The type of the tuple's first component.</typeparam> /// <typeparam name="T2">The type of the tuple's second component.</typeparam> public class WTuple<T1, T2> : IStructuralEquatable, IStructuralComparable, IComparable, IWTuple { private T1 _item1; private T2 _item2; #region ImplementedInterfaces Int32 IStructuralEquatable.GetHashCode(IEqualityComparer comparer) { return comparer.GetHashCode(_item1); } Boolean IStructuralEquatable.Equals(Object other, IEqualityComparer comparer) { if (other == null) return false; WTuple<T1, T2> objTuple = other as WTuple<T1, T2>;//Tuple<t1, t2=""> objTuple = other as Tuple<t1, t2="">; if (objTuple == null) { return false; } return comparer.Equals(_item1, objTuple._item1) && comparer.Equals(_item2, objTuple._item2); } Int32 IStructuralComparable.CompareTo(Object other, IComparer comparer) { if (other == null) return 1; WTuple<T1, T2> objTuple = other as WTuple<T1, T2>;//Tuple<t1, t2=""> objTuple = other as Tuple<t1, t2="">; if (objTuple == null) { throw new ArgumentException("ArgumentException_TupleIncorrectType", "other");//ArgumentException(Environment.GetResourceString("ArgumentException_TupleIncorrectType", this.GetType().ToString()), "other"); } int c = 0; c = comparer.Compare(_item1, objTuple._item1); if (c != 0) return c; return comparer.Compare(_item2, objTuple._item2); } Int32 IComparable.CompareTo(Object obj) { return ((IStructuralComparable)this).CompareTo(obj, Comparer<object>.Default); } Int32 IWTuple.GetHashCode(IEqualityComparer comparer) { return ((IStructuralEquatable)this).GetHashCode(comparer); } string IWTuple.ToString(StringBuilder sb) { sb.Append(_item1); sb.Append(", "); sb.Append(_item2); sb.Append(")"); return sb.ToString(); } int IWTuple.Size { get { return 2; } } #endregion #region WTuple /// <summary> /// Initializes a new instance of the System.WTuple&lt;T1,T2&gt; class. /// </summary> /// <param name="item1">The value of the tuple's first component.</param> /// <param name="item2">The value of the tuple's second component.</param> public WTuple(T1 item1, T2 item2) { _item1 = item1; _item2 = item2; } /// <summary> /// Gets or sets the value of the current System.WTuple&lt;T1,T2&gt; object's first component. /// </summary> public T1 Item1 { get { return _item1; } set { _item1 = value; } } /// <summary> /// Gets or sets the value of the current System.WTuple&lt;T1,T2&gt; object's second component. /// </summary> public T2 Item2 { get { return _item2; } set { _item2 = value; } } /// <summary> /// Returns a value that indicates whether the current System.WTuple&lt;T1,T2&gt; object /// is equal to a specified object. /// </summary> /// <param name="obj">The object to compare with this instance.</param> /// <returns>true if the current instance is equal to the specified object; otherwise, /// false.</returns> public override Boolean Equals(Object obj) { return ((IStructuralEquatable)this).Equals(obj, EqualityComparer<object>.Default); } /// <summary> /// Returns the hash code for the current System.WTuple&lt;T1,T2&gt; object. /// </summary> /// <returns>A 32-bit signed integer hash code.</returns> public override int GetHashCode() { return ((IStructuralEquatable)this).GetHashCode(EqualityComparer<object>.Default); } /// <summary> /// Returns a string that represents the value of this System.WTuple&lt;T1,T2&gt; instance. /// </summary> /// <returns>The string representation of this System.WTuple&lt;T1,T2&gt; object.</returns> public override string ToString() { StringBuilder sb = new StringBuilder(); sb.Append("("); return ((IWTuple)this).ToString(sb); } #endregion } } 

Answer 3

你只有ItemX属性的getter，没错，但是我find了一个方法来首先实例化一个具有空值的tupple并填充它们。

如果你做这样的事情：

 Dictionary <string, Tuple<string, string>> mydic = new Dictionary<string,Tuple<string,string>>(); Tuple<string, string> tplTemp = new Tuple<string, string>("", ""); mydic.TryGetValue("akey", out tplTemp); 

作为outparameter passing的tplTemp将从集合中获得2个项目值。 所以这是一种可以帮助某人的方法。