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从身份识别器翻译成普通身份识别器的最佳方式
原标题:Best way to translate from IDictionary to a generic IDictionary
  • 时间:2010-06-02 22:13:28
  •  标签:
  • c#
  • generics

我想通过“<代码”类型的财产暴露的电离层。 IDictionary<string,active>. 转换工作令人惊讶,因为我不知道什么是的。 Cast<>:. IDictionary to.

Best I ve got:

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

如果有:<代码>的基本类型 IDictionary不执行IDictionary<string,active>, 您不能投标,期限。 如果是的话,则通过<代码>(IDictionary<string, Dynamic>) 在当地投放。 Var 就足够了。

如果没有,你可以做两件事:

  1. Copy the IDictionary to your generic type.
  2. Build an Adapter class that accepts the IDictionary as a dependency and implements the generic IDictionary you want, mapping calls from one to the other.

<><>Edit>: 刚贴出的样本代码将复印字典,无论何时打到!。 我将在某个时候再次提出某些建议守则。

<><>>

您的样本代码法作为复制数据的手段是坚实的,但复制件应当贴在册,或重新复制时间。 d 我建议你将实际翻译法作为单独的方法,并要求从你的财产中第一次使用。 例如:

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);            
}

现在,这种做法显然有合意......如果需要更新数据的话? 你们必须把翻译作品重新开销,等等。

<><>>>

这是我的首选做法。

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);

现在,这种做法显然也有同感,最明显的是<代码>。 钥匙 (and Value and any others that Return ICollection on IDictionary has to re a new range for each calls. 但是,这仍然允许采取最灵活的做法,因为它确保了数据始终如一。

问题回答

Unless the Backing category for the IDictionary instance have useds IDictionary<string,dynamic> (类似于Dictionary<string,dynamic>) 然后向您提供打赢笔。 <代码>Cast<>> 方法仅对下列方法有用:IE 数和代数;T>值和正常投放量无选择。

提供<代码>数据 IDictionary<string,dynamic>很重要,因此不能继续并将其作为加以储存。 Dictionary<string,dynamic> from the first?

这里完全采用最高答案所建议的办法。 这太大,不能算作评论。

    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;
        }
    }

你们需要使用钥匙。

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




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