C# 将KeyValuePair强制转换为KeyValuePair
最简单的施展方式是什么:C# 将KeyValuePair强制转换为KeyValuePair,c#,.net,C#,.net,最简单的施展方式是什么: IList<KeyValuePair<Guid, object>> 到 无循环等。如果您有KeyValuePair k,则可以执行以下操作: new KeyValuePair<string, object>(k.Key.ToString(), k.Value); 不能在KeyValuePair和KeyValuePair之间强制转换,它们是不兼容的类型,它们的IList也是如此,除非您使用的类同时实现了这两种类型。通过使用ToStr
IList<KeyValuePair<Guid, object>>
到
无循环等。如果您有KeyValuePair k,则可以执行以下操作:
new KeyValuePair<string, object>(k.Key.ToString(), k.Value);
不能在KeyValuePair和KeyValuePair之间强制转换,它们是不兼容的类型,它们的IList也是如此,除非您使用的类同时实现了这两种类型。通过使用ToString将Guid转换为字符串,可以创建具有类似值的新Guid:
要对IList执行此操作,必须执行某种循环。为了可读性,我建议使用LINQ:
IList<KeyValuePair<string, object>> newList = oldList
.Select(x => new KeyValuePair<string, object>(x.Key.ToString(), x.Value))
.ToList();
当你说:
没有回路等
这是否意味着您有多个KeyValuePairs?所以说你有IEnumerable并且想要IEnumerable。。。您必须执行某种形式的循环来转换每个值:
因此,您可以非常轻松地使用LINQ语句:
IEnumerable<KeyValuePair<Guid, Object>> x = ...;
var newPairs = x.Select(kvp=> new KeyValuePair<string, object>(kvp.Key.ToString(), kvp.Value));
这至少相当干净…您可以创建一个无循环的包装IList类,但您必须提供转换派生的父级,父级派生的自己
用法:
var originalList = new List<KeyValuePair<Guid, object>>();
originalList.Add(new KeyValuePair<Guid, object>(Guid.Empty, "blabla"));
originalList.Add(new KeyValuePair<Guid, object>(Guid.NewGuid(), "foobar"));
var list = new ConvertibleList<KeyValuePair<string, object>, KeyValuePair<Guid, object>>(originalList,
(k) => new KeyValuePair<string, object>(k.Key.ToString("N"), k.Value),
(k) => new KeyValuePair<Guid, object>(new Guid(k.Key), k.Value));
包装类:
public class ConvertibleList<Derived,Parent> : IList<Derived> {
private IList<Parent> m_List;
private Func<Parent, Derived> m_ParentToDerived;
private Func<Derived, Parent> m_DerivedToParent;
private class Enumerator : IEnumerator<Derived> {
private IEnumerator<Parent> m_Enumerator;
private Func<Parent, Derived> m_ParentToDerived;
public Enumerator(IEnumerator<Parent> enumerator, Func<Parent, Derived> parentToDerived) {
m_Enumerator = enumerator;
m_ParentToDerived = parentToDerived;
}
public Derived Current {
get { return m_ParentToDerived(m_Enumerator.Current); }
}
object IEnumerator.Current {
get { return m_ParentToDerived(m_Enumerator.Current); }
}
public bool MoveNext() {
return m_Enumerator.MoveNext();
}
public void Reset() {
m_Enumerator.Reset();
}
public void Dispose() {
m_Enumerator.Dispose();
}
}
private class Enumerable : IEnumerable<Derived> {
private IEnumerable<Parent> m_Parent;
private Func<Parent, Derived> m_ParentToDerived;
public Enumerable(IEnumerable<Parent> parent, Func<Parent, Derived> parentToDerived) {
m_Parent = parent;
m_ParentToDerived = parentToDerived;
}
public IEnumerator<Derived> GetEnumerator() {
return new Enumerator(m_Parent.GetEnumerator(), m_ParentToDerived);
}
IEnumerator IEnumerable.GetEnumerator() {
return new Enumerator(m_Parent.GetEnumerator(), m_ParentToDerived);
}
}
public ConvertibleList(IList<Parent> list, Func<Parent, Derived> parentToDerived, Func<Derived, Parent> derivedToParent) {
if (list == null) {
throw new ArgumentNullException("list");
}
m_List = list;
m_ParentToDerived = parentToDerived;
m_DerivedToParent = derivedToParent;
}
public int IndexOf(Derived item) {
return m_List.IndexOf(m_DerivedToParent(item));
}
public void Insert(int index, Derived item) {
m_List.Insert(index, m_DerivedToParent(item));
}
public void RemoveAt(int index) {
m_List.RemoveAt(index);
}
public Derived this[int index] {
get { return m_ParentToDerived(m_List[index]); }
set { m_List[index] = m_DerivedToParent(value); }
}
public void Add(Derived item) {
m_List.Add(m_DerivedToParent(item));
}
public void Clear() {
m_List.Clear();
}
public bool Contains(Derived item) {
return m_List.Contains(m_DerivedToParent(item));
}
public void CopyTo(Derived[] array, int arrayIndex) {
var parentArray = new Parent[array.Length];
for (var i = 0; i < array.Length; i++) {
parentArray[i] = m_DerivedToParent(array[i]);
}
m_List.CopyTo(parentArray, arrayIndex);
}
public int Count {
get { return m_List.Count; }
}
public bool IsReadOnly {
get { return m_List.IsReadOnly; }
}
public bool Remove(Derived item) {
return m_List.Remove(m_DerivedToParent(item));
}
public IEnumerator<Derived> GetEnumerator() {
return new Enumerator(m_List.GetEnumerator(), m_ParentToDerived);
}
IEnumerator IEnumerable.GetEnumerator() {
return new Enumerator(m_List.GetEnumerator(), m_ParentToDerived);
}
}
var pair=new KeyValuePairguidObj.Key.ToString,guidObj.Value;你不能施放,你必须转换。对不起大家,忘记犯了一个错误-忘记了IList位!如果它真的是IList或List,那么您可以使用List.ConvertAll,它也会隐式循环。根据您的编辑,它是:
var originalList = new List<KeyValuePair<Guid, object>>();
originalList.Add(new KeyValuePair<Guid, object>(Guid.Empty, "blabla"));
originalList.Add(new KeyValuePair<Guid, object>(Guid.NewGuid(), "foobar"));
var list = new ConvertibleList<KeyValuePair<string, object>, KeyValuePair<Guid, object>>(originalList,
(k) => new KeyValuePair<string, object>(k.Key.ToString("N"), k.Value),
(k) => new KeyValuePair<Guid, object>(new Guid(k.Key), k.Value));
public class ConvertibleList<Derived,Parent> : IList<Derived> {
private IList<Parent> m_List;
private Func<Parent, Derived> m_ParentToDerived;
private Func<Derived, Parent> m_DerivedToParent;
private class Enumerator : IEnumerator<Derived> {
private IEnumerator<Parent> m_Enumerator;
private Func<Parent, Derived> m_ParentToDerived;
public Enumerator(IEnumerator<Parent> enumerator, Func<Parent, Derived> parentToDerived) {
m_Enumerator = enumerator;
m_ParentToDerived = parentToDerived;
}
public Derived Current {
get { return m_ParentToDerived(m_Enumerator.Current); }
}
object IEnumerator.Current {
get { return m_ParentToDerived(m_Enumerator.Current); }
}
public bool MoveNext() {
return m_Enumerator.MoveNext();
}
public void Reset() {
m_Enumerator.Reset();
}
public void Dispose() {
m_Enumerator.Dispose();
}
}
private class Enumerable : IEnumerable<Derived> {
private IEnumerable<Parent> m_Parent;
private Func<Parent, Derived> m_ParentToDerived;
public Enumerable(IEnumerable<Parent> parent, Func<Parent, Derived> parentToDerived) {
m_Parent = parent;
m_ParentToDerived = parentToDerived;
}
public IEnumerator<Derived> GetEnumerator() {
return new Enumerator(m_Parent.GetEnumerator(), m_ParentToDerived);
}
IEnumerator IEnumerable.GetEnumerator() {
return new Enumerator(m_Parent.GetEnumerator(), m_ParentToDerived);
}
}
public ConvertibleList(IList<Parent> list, Func<Parent, Derived> parentToDerived, Func<Derived, Parent> derivedToParent) {
if (list == null) {
throw new ArgumentNullException("list");
}
m_List = list;
m_ParentToDerived = parentToDerived;
m_DerivedToParent = derivedToParent;
}
public int IndexOf(Derived item) {
return m_List.IndexOf(m_DerivedToParent(item));
}
public void Insert(int index, Derived item) {
m_List.Insert(index, m_DerivedToParent(item));
}
public void RemoveAt(int index) {
m_List.RemoveAt(index);
}
public Derived this[int index] {
get { return m_ParentToDerived(m_List[index]); }
set { m_List[index] = m_DerivedToParent(value); }
}
public void Add(Derived item) {
m_List.Add(m_DerivedToParent(item));
}
public void Clear() {
m_List.Clear();
}
public bool Contains(Derived item) {
return m_List.Contains(m_DerivedToParent(item));
}
public void CopyTo(Derived[] array, int arrayIndex) {
var parentArray = new Parent[array.Length];
for (var i = 0; i < array.Length; i++) {
parentArray[i] = m_DerivedToParent(array[i]);
}
m_List.CopyTo(parentArray, arrayIndex);
}
public int Count {
get { return m_List.Count; }
}
public bool IsReadOnly {
get { return m_List.IsReadOnly; }
}
public bool Remove(Derived item) {
return m_List.Remove(m_DerivedToParent(item));
}
public IEnumerator<Derived> GetEnumerator() {
return new Enumerator(m_List.GetEnumerator(), m_ParentToDerived);
}
IEnumerator IEnumerable.GetEnumerator() {
return new Enumerator(m_List.GetEnumerator(), m_ParentToDerived);
}
}