Najlepszy sposób na przetłumaczenie z IDictionary na ogólne IDictionary

Question

Mam pole IDictionary, które chciałbym ujawnić poprzez właściwość typu IDictionary<string, dynamic> konwersja jest zaskakująco trudne, ponieważ nie mam pojęcia, co mogę .Cast<>() IDictionary to.

Najlepszy mam:

IDictionary properties; 
protected virtual IDictionary<string, dynamic> Properties { 
    get { 
     return _properties.Keys.Cast<string>() 
       .ToDictionary(name=>name, name=> _properties[name] as dynamic); 
     } 
    } 

Answer 1

Jeżeli bazowy typ IDictionary nie implementuje IDictionary<string, dynamic>, nie można rzutować obiektu, kropka. Jeśli tak, wystarczy zwykła obsada przez (IDictionary<string, dynamic>)localVar.

Jeśli tak nie jest, są dwie rzeczy, które możesz zrobić:

1. Kopiuje IDictionary do typu rodzajowego.
2. Zbuduj klasę Adapter, która akceptuje IDictionary jako zależność i implementuje typowe IDictionary, które chcesz, mapując połączenia z jednego do drugiego.

Edit: Przykładowy kod, który właśnie pisał skopiuje słownika za każdym razem robi się nazywa! Będę edytować ponownie za chwilę z sugerowanym kodem.

Wariant 1

Twoje podejście przykładowy kod jest stałe jako sposób kopiowania danych, ale kopia powinna być buforowane lub masz zamiar skopiować wiele razy. Sugeruję, abyś wstawił rzeczywisty kod tłumaczenia do osobnej metody i zadzwonił do niego z twojej nieruchomości przy pierwszym użyciu. Na przykład:

private IDictionary dataLayerProperties; 
private IDictionary<string, dynamic> translatedProperties = null; 
protected virtual IDictionary<string, dynamic> Properties 
{ 
    if(translatedProperties == null) 
    { 
     translatedProperties = TranslateDictionary(dataLayerProperties);   
    } 
    return translatedProperties; 
} 

public IDictionary<string, dynamic> TranslateDictionary(IDictionary values) 
{ 
    return values.Keys.Cast<string>().ToDictionary(key=>key, key => values[key] as dynamic);    
} 

Istnieje oczywiste przeciwwskazanie do tego podejścia ... co zrobić, jeśli dataLayerProperties wymaga odświeżenia? Musisz iść do ustawiania translatedProperties ponownie wartość null itp

Opcja 2

To jest mój preferowany podejście.

public class TranslatedDictionary : IDictionary<string, dynamic> 
{ 
    private IDictionary Original = null; 

    public TranslatedDictionary(IDictionary original) 
    { 
     Original = original; 
    } 
    public ICollection<string> Keys 
    { 
     get 
     { 
      return Original.Keys.Cast<string>().ToList(); 
     } 
    } 

    public dynamic this[string key] 
    { 
     get 
     { 
      return Original[key] as dynamic; 
     } 
     set 
     { 
      Original[key] = value; 
     } 
    } 
    // and so forth, for each method of IDictionary<string, dynamic> 
} 

//elsewhere, using your original property and field names: 
Properties = new TranslatedDictionary(properties); 

Teraz istnieją oczywiste zalety tego podejścia, jak również, najbardziej rażące jest fakt, że Keys (i wartość, a wszystko, co zwraca ICollection na IDictionary musi powrócić nową tablicę na każde wezwanie. Ale pozwala to nadal najbardziej elastycznego podejścia, ponieważ zapewnia, że ​​dane są zawsze aktualne.

Answer 2

Musisz użyć KeyValuePair.

myDictionary.Cast<KeyValuePair<Type1, Type2>>() 

Answer 3

ile rodzaj podkładu na przykład IDictionary już implementuje IDictionary<string,dynamic> (jak Dictionary<string,dynamic>), a następnie rzucając nie pomoże. metoda jest Cast<>() przydatne tylko przy zwracaniu wartości IEnumerable<T> i normalnym c asting nie jest opcją.

Jeśli podanie danych w postaci IDictionary<string,dynamic> jest ważne, to dlaczego nie od razu zapisać je jako numer Dictionary<string,dynamic>?

Answer 4

Oto pełna implementacja metody zalecanej w górnej odpowiedzi. To było zbyt duże, aby zmieścić się w komentarzu.

using System; 
    using System.Collections; 
    using System.Collections.Generic; 
    using System.Diagnostics.CodeAnalysis; 
    using System.Linq; 

    /// <summary> 
    /// The casted dictionary. 
    /// </summary> 
    /// <typeparam name="TKey"> 
    /// The key type 
    /// </typeparam> 
    /// <typeparam name="TValue"> 
    /// The value type 
    /// </typeparam> 
    public class CastedDictionary<TKey, TValue> : IDictionary<TKey, TValue> 
    { 
     /// <summary> 
     /// The original dictionary. 
     /// </summary> 
     private readonly IDictionary originalDictionary; 

     /// <summary> 
     /// The keys. 
     /// </summary> 
     private ICollection<TKey> keys; 

     /// <summary> 
     /// The values. 
     /// </summary> 
     private ICollection<TValue> values; 

     /// <summary> 
     /// Initializes a new instance of the <see cref="CastedDictionary{TKey,TValue}"/> class. 
     /// </summary> 
     /// <param name="original"> 
     /// The original. 
     /// </param> 
     public CastedDictionary(IDictionary original) 
      : this() 
     { 
      if (original == null) 
      { 
       throw new ArgumentNullException("original"); 
      } 

      this.originalDictionary = original; 
     } 

     /// <summary> 
     /// Prevents a default instance of the <see cref="CastedDictionary{TKey, TValue}"/> class from being created. 
     /// </summary> 
     [SuppressMessage("StyleCop.CSharp.DocumentationRules", "SA1642:ConstructorSummaryDocumentationMustBeginWithStandardText", Justification = "Style Cop does not analyze private generic class constructor comments properly")] 
     private CastedDictionary() 
     { 
     } 

     /// <summary> 
     /// Gets the number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </summary> 
     /// <returns> 
     /// The number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </returns> 
     public int Count 
     { 
      get 
      { 
       return this.originalDictionary.Count; 
      } 
     } 

     /// <summary> 
     /// Gets a value indicating whether the <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only. 
     /// </summary> 
     /// <returns> 
     /// true if the <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only; otherwise, false. 
     /// </returns> 
     public bool IsReadOnly 
     { 
      get 
      { 
       return this.originalDictionary.IsReadOnly; 
      } 
     } 

     /// <summary> 
     /// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the keys of the <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </summary> 
     /// <returns> 
     /// An <see cref="T:System.Collections.Generic.ICollection`1"/> containing the keys of the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </returns> 
     public ICollection<TKey> Keys 
     { 
      get 
      { 
       return this.keys ?? (this.keys = this.originalDictionary.Keys.Cast<TKey>().ToList()); 
      } 
     } 

     /// <summary> 
     /// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the values in the <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </summary> 
     /// <returns> 
     /// An <see cref="T:System.Collections.Generic.ICollection`1"/> containing the values in the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </returns> 
     public ICollection<TValue> Values 
     { 
      get 
      { 
       return this.values ?? (this.values = this.originalDictionary.Values.Cast<TValue>().ToList()); 
      } 
     } 

     /// <summary> 
     /// Gets or sets the element with the specified key. 
     /// </summary> 
     /// <returns> 
     /// The element with the specified key. 
     /// </returns> 
     /// <param name="key">The key of the element to get or set.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.Collections.Generic.KeyNotFoundException">The property is retrieved and <paramref name="key"/> is not found.</exception><exception cref="T:System.NotSupportedException">The property is set and the <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception> 
     public TValue this[TKey key] 
     { 
      get 
      { 
       return (TValue)this.originalDictionary[key]; 
      } 

      set 
      { 
       this.originalDictionary[key] = value; 
      } 
     } 

     /// <summary> 
     /// Returns an enumerator that iterates through the collection. 
     /// </summary> 
     /// <returns> 
     /// A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection. 
     /// </returns> 
     /// <filterpriority>1</filterpriority> 
     public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() 
     { 
      return this.originalDictionary.Cast<KeyValuePair<TKey, TValue>>().GetEnumerator(); 
     } 

     /// <summary> 
     /// Returns an enumerator that iterates through a collection. 
     /// </summary> 
     /// <returns> 
     /// An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection. 
     /// </returns> 
     /// <filterpriority>2</filterpriority> 
     IEnumerator IEnumerable.GetEnumerator() 
     { 
      return this.GetEnumerator(); 
     } 

     /// <summary> 
     /// Adds an item to the <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </summary> 
     /// <param name="item">The object to add to the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only.</exception> 
     public void Add(KeyValuePair<TKey, TValue> item) 
     { 
      this.originalDictionary.Add(item.Key, item.Value); 
     } 

     /// <summary> 
     /// Removes all items from the <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </summary> 
     /// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only. </exception> 
     public void Clear() 
     { 
      this.originalDictionary.Clear(); 
     } 

     /// <summary> 
     /// Determines whether the <see cref="T:System.Collections.Generic.ICollection`1"/> contains a specific value. 
     /// </summary> 
     /// <returns> 
     /// true if <paramref name="item"/> is found in the <see cref="T:System.Collections.Generic.ICollection`1"/>; otherwise, false. 
     /// </returns> 
     /// <param name="item">The object to locate in the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param> 
     public bool Contains(KeyValuePair<TKey, TValue> item) 
     { 
      return this.originalDictionary.Contains(item.Key) && EqualityComparer<TValue>.Default.Equals(this[item.Key], item.Value); 
     } 

     /// <summary> 
     /// Copies the elements of the <see cref="T:System.Collections.Generic.ICollection`1"/> to an <see cref="T:System.Array"/>, starting at a particular <see cref="T:System.Array"/> index. 
     /// </summary> 
     /// <param name="array">The one-dimensional <see cref="T:System.Array"/> that is the destination of the elements copied from <see cref="T:System.Collections.Generic.ICollection`1"/>. The <see cref="T:System.Array"/> must have zero-based indexing.</param><param name="arrayIndex">The zero-based index in <paramref name="array"/> at which copying begins.</param><exception cref="T:System.ArgumentNullException"><paramref name="array"/> is null.</exception><exception cref="T:System.ArgumentOutOfRangeException"><paramref name="arrayIndex"/> is less than 0.</exception><exception cref="T:System.ArgumentException">The number of elements in the source <see cref="T:System.Collections.Generic.ICollection`1"/> is greater than the available space from <paramref name="arrayIndex"/> to the end of the destination <paramref name="array"/>.</exception> 
     public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex) 
     { 
      this.originalDictionary.CopyTo(array, arrayIndex); 
     } 

     /// <summary> 
     /// Removes the first occurrence of a specific object from the <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </summary> 
     /// <returns> 
     /// true if <paramref name="item"/> was successfully removed from the <see cref="T:System.Collections.Generic.ICollection`1"/>; otherwise, false. This method also returns false if <paramref name="item"/> is not found in the original <see cref="T:System.Collections.Generic.ICollection`1"/>. 
     /// </returns> 
     /// <param name="item">The object to remove from the <see cref="T:System.Collections.Generic.ICollection`1"/>.</param><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"/> is read-only.</exception> 
     public bool Remove(KeyValuePair<TKey, TValue> item) 
     { 
      if (this.Contains(item)) 
      { 
       this.originalDictionary.Remove(item.Key); 
       return true; 
      } 

      return false; 
     } 

     /// <summary> 
     /// Determines whether the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the specified key. 
     /// </summary> 
     /// <returns> 
     /// true if the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the key; otherwise, false. 
     /// </returns> 
     /// <param name="key">The key to locate in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception> 
     public bool ContainsKey(TKey key) 
     { 
      return this.originalDictionary.Contains(key); 
     } 

     /// <summary> 
     /// Adds an element with the provided key and value to the <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </summary> 
     /// <param name="key">The object to use as the key of the element to add.</param><param name="value">The object to use as the value of the element to add.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.ArgumentException">An element with the same key already exists in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.</exception><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception> 
     public void Add(TKey key, TValue value) 
     { 
      this.originalDictionary.Add(key, value); 
     } 

     /// <summary> 
     /// Removes the element with the specified key from the <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </summary> 
     /// <returns> 
     /// true if the element is successfully removed; otherwise, false. This method also returns false if <paramref name="key"/> was not found in the original <see cref="T:System.Collections.Generic.IDictionary`2"/>. 
     /// </returns> 
     /// <param name="key">The key of the element to remove.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception><exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.</exception> 
     public bool Remove(TKey key) 
     { 
      if (this.ContainsKey(key)) 
      { 
       this.originalDictionary.Remove(key); 
       return true; 
      } 

      return false; 
     } 

     /// <summary> 
     /// Gets the value associated with the specified key. 
     /// </summary> 
     /// <returns> 
     /// true if the object that implements <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the specified key; otherwise, false. 
     /// </returns> 
     /// <param name="key">The key whose value to get.</param><param name="value">When this method returns, the value associated with the specified key, if the key is found; otherwise, the default value for the type of the <paramref name="value"/> parameter. This parameter is passed uninitialized.</param><exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null.</exception> 
     public bool TryGetValue(TKey key, out TValue value) 
     { 
// ReSharper disable CompareNonConstrainedGenericWithNull 
      if (typeof(TKey).IsValueType == false && key == null) 
// ReSharper restore CompareNonConstrainedGenericWithNull 
      { 
       throw new ArgumentNullException("key"); 
      } 

      if (this.ContainsKey(key)) 
      { 
       value = this[key]; 
       return true; 
      } 

      value = default(TValue); 
      return false; 
     } 
    }