NameValueCollection Class
System.Collections.Specialized.NameObjectCollectionBase
System.Collections.Specialized.NameValueCollection
System.Net.WebHeaderCollection
System.Web.HttpClientCertificate
Assembly: System (in System.dll)
The NameValueCollection type exposes the following members.
Name | Description | |
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![]() ![]() | NameValueCollection() | Initializes a new instance of the NameValueCollection class that is empty, has the default initial capacity and uses the default case-insensitive hash code provider and the default case-insensitive comparer. |
![]() ![]() | NameValueCollection(IEqualityComparer) | Initializes a new instance of the NameValueCollection class that is empty, has the default initial capacity, and uses the specified IEqualityComparer object. |
![]() ![]() | NameValueCollection(Int32) | Initializes a new instance of the NameValueCollection class that is empty, has the specified initial capacity and uses the default case-insensitive hash code provider and the default case-insensitive comparer. |
![]() ![]() | NameValueCollection(NameValueCollection) | Copies the entries from the specified NameValueCollection to a new NameValueCollection with the same initial capacity as the number of entries copied and using the same hash code provider and the same comparer as the source collection. |
![]() ![]() | NameValueCollection(IHashCodeProvider, IComparer) | Obsolete. Initializes a new instance of the NameValueCollection class that is empty, has the default initial capacity and uses the specified hash code provider and the specified comparer. |
![]() ![]() | NameValueCollection(Int32, IEqualityComparer) | Initializes a new instance of the NameValueCollection class that is empty, has the specified initial capacity, and uses the specified IEqualityComparer object. |
![]() ![]() | NameValueCollection(Int32, NameValueCollection) | Copies the entries from the specified NameValueCollection to a new NameValueCollection with the specified initial capacity or the same initial capacity as the number of entries copied, whichever is greater, and using the default case-insensitive hash code provider and the default case-insensitive comparer. |
![]() | NameValueCollection(SerializationInfo, StreamingContext) | Initializes a new instance of the NameValueCollection class that is serializable and uses the specified System.Runtime.Serialization.SerializationInfo and System.Runtime.Serialization.StreamingContext. |
![]() ![]() | NameValueCollection(Int32, IHashCodeProvider, IComparer) | Obsolete. Initializes a new instance of the NameValueCollection class that is empty, has the specified initial capacity and uses the specified hash code provider and the specified comparer. |
Name | Description | |
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![]() ![]() | AllKeys | Gets all the keys in the NameValueCollection. |
![]() ![]() | Count | Gets the number of key/value pairs contained in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | IsReadOnly | Gets or sets a value indicating whether the NameObjectCollectionBase instance is read-only. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | Item[Int32] | Gets the entry at the specified index of the NameValueCollection. |
![]() ![]() | Item[String] | Gets or sets the entry with the specified key in the NameValueCollection. |
![]() ![]() | Keys | Gets a NameObjectCollectionBase.KeysCollection instance that contains all the keys in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
Name | Description | |
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![]() ![]() | Add(NameValueCollection) | Copies the entries in the specified NameValueCollection to the current NameValueCollection. |
![]() ![]() | Add(String, String) | Adds an entry with the specified name and value to the NameValueCollection. |
![]() ![]() | BaseAdd | Adds an entry with the specified key and value into the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseClear | Removes all entries from the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseGet(Int32) | Gets the value of the entry at the specified index of the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseGet(String) | Gets the value of the first entry with the specified key from the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseGetAllKeys | Returns a String array that contains all the keys in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() | BaseGetAllValues() | Returns an Object array that contains all the values in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() | BaseGetAllValues(Type) | Returns an array of the specified type that contains all the values in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseGetKey | Gets the key of the entry at the specified index of the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseHasKeys | Gets a value indicating whether the NameObjectCollectionBase instance contains entries whose keys are not null. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseRemove | Removes the entries with the specified key from the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseRemoveAt | Removes the entry at the specified index of the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseSet(Int32, Object) | Sets the value of the entry at the specified index of the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | BaseSet(String, Object) | Sets the value of the first entry with the specified key in the NameObjectCollectionBase instance, if found; otherwise, adds an entry with the specified key and value into the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | Clear | Invalidates the cached arrays and removes all entries from the NameValueCollection. |
![]() | CopyTo | Copies the entire NameValueCollection to a compatible one-dimensional Array, starting at the specified index of the target array. |
![]() ![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() ![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() ![]() | Get(Int32) | Gets the values at the specified index of the NameValueCollection combined into one comma-separated list. |
![]() ![]() | Get(String) | Gets the values associated with the specified key from the NameValueCollection combined into one comma-separated list. |
![]() ![]() | GetEnumerator | Returns an enumerator that iterates through the NameObjectCollectionBase. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() ![]() | GetKey | Gets the key at the specified index of the NameValueCollection. |
![]() | GetObjectData | Implements the ISerializable interface and returns the data needed to serialize the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() ![]() | GetValues(Int32) | Gets the values at the specified index of the NameValueCollection. |
![]() ![]() | GetValues(String) | Gets the values associated with the specified key from the NameValueCollection. |
![]() ![]() | HasKeys | Gets a value indicating whether the NameValueCollection contains keys that are not null. |
![]() ![]() | InvalidateCachedArrays | Resets the cached arrays of the collection to null. |
![]() ![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | OnDeserialization | Implements the ISerializable interface and raises the deserialization event when the deserialization is complete. (Inherited from NameObjectCollectionBase.) |
![]() ![]() | Remove | Removes the entries with the specified key from the NameObjectCollectionBase instance. |
![]() ![]() | Set | Sets the value of an entry in the NameValueCollection. |
![]() ![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
Name | Description | |
---|---|---|
![]() ![]() ![]() | ICollection.CopyTo | Copies the entire NameObjectCollectionBase to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from NameObjectCollectionBase.) |
![]() ![]() ![]() | ICollection.IsSynchronized | Gets a value indicating whether access to the NameObjectCollectionBase object is synchronized (thread safe). (Inherited from NameObjectCollectionBase.) |
![]() ![]() ![]() | ICollection.SyncRoot | Gets an object that can be used to synchronize access to the NameObjectCollectionBase object. (Inherited from NameObjectCollectionBase.) |
This collection is based on the NameObjectCollectionBase class. However, unlike the NameObjectCollectionBase, this class stores multiple string values under a single key.
This class can be used for headers, query strings and form data.
Each element is a key/value pair.
Collections of this type do not preserve the ordering of element, and no particular ordering is guaranteed when enumerating the collection.
The capacity of a NameValueCollection is the number of elements the NameValueCollection can hold. As elements are added to a NameValueCollection, the capacity is automatically increased as required through reallocation.
The hash code provider dispenses hash codes for keys in the NameValueCollection. The default hash code provider is the CaseInsensitiveHashCodeProvider.
The comparer determines whether two keys are equal. The default comparer is the CaseInsensitiveComparer.
In .NET Framework version 1.0, this class uses culture-sensitive string comparisons. However, in .NET Framework version 1.1 and later, this class uses CultureInfo.InvariantCulture when comparing strings. For more information about how culture affects comparisons and sorting, see Comparing and Sorting Data for a Specific Culture Comparing and Sorting Data for a Specific Cultureand Performing Culture-Insensitive String Operations.
null is allowed as a key or as a value.
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The Get method does not distinguish between null which is returned because the specified key is not found and null which is returned because the value associated with the key is null. |
Topic | Location |
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How to: Read Application Settings from the Web.config File | Configuring ASP .NET Web Applications |
How to: Read Application Settings from the Web.config File | Configuring ASP .NET Web Applications |
using System; using System.Collections; using System.Collections.Specialized; public class SamplesNameValueCollection { public static void Main() { // Creates and initializes a new NameValueCollection. NameValueCollection myCol = new NameValueCollection(); myCol.Add( "red", "rojo" ); myCol.Add( "green", "verde" ); myCol.Add( "blue", "azul" ); myCol.Add( "red", "rouge" ); // Displays the values in the NameValueCollection in two different ways. Console.WriteLine( "Displays the elements using the AllKeys property and the Item (indexer) property:" ); PrintKeysAndValues( myCol ); Console.WriteLine( "Displays the elements using GetKey and Get:" ); PrintKeysAndValues2( myCol ); // Gets a value either by index or by key. Console.WriteLine( "Index 1 contains the value {0}.", myCol[1] ); Console.WriteLine( "Key \"red\" has the value {0}.", myCol["red"] ); Console.WriteLine(); // Copies the values to a string array and displays the string array. String[] myStrArr = new String[myCol.Count]; myCol.CopyTo( myStrArr, 0 ); Console.WriteLine( "The string array contains:" ); foreach ( String s in myStrArr ) Console.WriteLine( " {0}", s ); Console.WriteLine(); // Searches for a key and deletes it. myCol.Remove( "green" ); Console.WriteLine( "The collection contains the following elements after removing \"green\":" ); PrintKeysAndValues( myCol ); // Clears the entire collection. myCol.Clear(); Console.WriteLine( "The collection contains the following elements after it is cleared:" ); PrintKeysAndValues( myCol ); } public static void PrintKeysAndValues( NameValueCollection myCol ) { Console.WriteLine( " KEY VALUE" ); foreach ( String s in myCol.AllKeys ) Console.WriteLine( " {0,-10} {1}", s, myCol[s] ); Console.WriteLine(); } public static void PrintKeysAndValues2( NameValueCollection myCol ) { Console.WriteLine( " [INDEX] KEY VALUE" ); for ( int i = 0; i < myCol.Count; i++ ) Console.WriteLine( " [{0}] {1,-10} {2}", i, myCol.GetKey(i), myCol.Get(i) ); Console.WriteLine(); } } /* This code produces the following output. Displays the elements using the AllKeys property and the Item (indexer) property: KEY VALUE red rojo,rouge green verde blue azul Displays the elements using GetKey and Get: [INDEX] KEY VALUE [0] red rojo,rouge [1] green verde [2] blue azul Index 1 contains the value verde. Key "red" has the value rojo,rouge. The string array contains: rojo,rouge verde azul The collection contains the following elements after removing "green": KEY VALUE red rojo,rouge blue azul The collection contains the following elements after it is cleared: KEY VALUE */
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
This implementation does not provide a synchronized (thread safe) wrapper for a NameValueCollection, but derived classes can create their own synchronized versions of the NameValueCollection using the SyncRoot property of the NameObjectCollectionBase class.
Enumerating through a collection is intrinsically not a thread safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.