ExpandoObject Class

Definition

Represents an object whose members can be dynamically added and removed at run time.

public ref class ExpandoObject sealed : System::Collections::Generic::ICollection<System::Collections::Generic::KeyValuePair<System::String ^, System::Object ^>>, System::Collections::Generic::IDictionary<System::String ^, System::Object ^>, System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<System::String ^, System::Object ^>>, System::ComponentModel::INotifyPropertyChanged, System::Dynamic::IDynamicMetaObjectProvider
public sealed class ExpandoObject : System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<string,object>>, System.Collections.Generic.IDictionary<string,object>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string,object>>, System.ComponentModel.INotifyPropertyChanged, System.Dynamic.IDynamicMetaObjectProvider
type ExpandoObject = class
    interface ICollection<KeyValuePair<string, obj>>
    interface seq<KeyValuePair<string, obj>>
    interface IEnumerable
    interface IDictionary<string, obj>
    interface INotifyPropertyChanged
    interface IDynamicMetaObjectProvider
type ExpandoObject = class
    interface IDynamicMetaObjectProvider
    interface IDictionary<string, obj>
    interface ICollection<KeyValuePair<string, obj>>
    interface seq<KeyValuePair<string, obj>>
    interface IEnumerable
    interface INotifyPropertyChanged
type ExpandoObject = class
    interface IDynamicMetaObjectProvider
    interface IDictionary<string, obj>
    interface INotifyPropertyChanged
    interface ICollection<KeyValuePair<string, obj>>
    interface seq<KeyValuePair<string, obj>>
    interface IEnumerable
Public NotInheritable Class ExpandoObject
Implements ICollection(Of KeyValuePair(Of String, Object)), IDictionary(Of String, Object), IDynamicMetaObjectProvider, IEnumerable(Of KeyValuePair(Of String, Object)), INotifyPropertyChanged
Inheritance
ExpandoObject
Implements

Remarks

The ExpandoObject class enables you to add and delete members of its instances at run time and also to set and get values of these members. This class supports dynamic binding, which enables you to use standard syntax like sampleObject.sampleMember instead of more complex syntax like sampleObject.GetAttribute("sampleMember").

The ExpandoObject class implements the standard Dynamic Language Runtime (DLR) interface IDynamicMetaObjectProvider, which enables you to share instances of the ExpandoObject class between languages that support the DLR interoperability model. For example, you can create an instance of the ExpandoObject class in C# and then pass it to an IronPython function. For more information, see Dynamic Language Runtime Overview and Introducing the ExpandoObject on the C# Frequently Asked Questions Web site.

The ExpandoObject class is an implementation of the dynamic object concept that enables getting, setting, and invoking members. If you want to define types that have their own dynamic dispatch semantics, use the DynamicObject class. If you want to define how dynamic objects participate in the interoperability protocol and manage DLR fast dynamic dispatch caching, create your own implementation of the IDynamicMetaObjectProvider interface.

Creating an Instance

In C#, to enable late binding for an instance of the ExpandoObject class, you must use the dynamic keyword. For more information, see Using Type dynamic.

In Visual Basic, dynamic operations are supported by late binding. For more information, see Early and Late Binding (Visual Basic).

The following code example demonstrates how to create an instance of the ExpandoObject class.

dynamic sampleObject = new ExpandoObject();
Dim sampleObject As Object = New ExpandoObject()

Adding New Members

You can add properties, methods, and events to instances of the ExpandoObject class.

The following code example demonstrates how to add a new property to an instance of the ExpandoObject class.

sampleObject.test = "Dynamic Property";
Console.WriteLine(sampleObject.test);
Console.WriteLine(sampleObject.test.GetType());
// This code example produces the following output:
// Dynamic Property
// System.String
sampleObject.Test = "Dynamic Property"
Console.WriteLine(sampleObject.test)
Console.WriteLine(sampleObject.test.GetType())
' This code example produces the following output:
' Dynamic Property
' System.String

The methods represent lambda expressions that are stored as delegates, which can be invoked when they are needed. The following code example demonstrates how to add a method that increments a value of the dynamic property.

sampleObject.number = 10;
sampleObject.Increment = (Action)(() => { sampleObject.number++; });

// Before calling the Increment method.
Console.WriteLine(sampleObject.number);

sampleObject.Increment();

// After calling the Increment method.
Console.WriteLine(sampleObject.number);
// This code example produces the following output:
// 10
// 11
sampleObject.Number = 10
sampleObject.Increment = Function() sampleObject.Number + 1
' Before calling the Increment method.
Console.WriteLine(sampleObject.number)

sampleObject.Increment.Invoke()

' After calling the Increment method.
Console.WriteLine(sampleObject.number)
' This code example produces the following output:
' 10
' 11

The following code example demonstrates how to add an event to an instance of the ExpandoObject class.

class Program  
{  
    static void Main(string[] args)  
    {  
        dynamic sampleObject = new ExpandoObject();  

        // Create a new event and initialize it with null.  
        sampleObject.sampleEvent = null;  

        // Add an event handler.  
        sampleObject.sampleEvent += new EventHandler(SampleHandler);  

        // Raise an event for testing purposes.  
        sampleObject.sampleEvent(sampleObject, new EventArgs());  
   }  

    // Event handler.  
    static void SampleHandler(object sender, EventArgs e)  
    {  
        Console.WriteLine("SampleHandler for {0} event", sender);  
    }  
}  
// This code example produces the following output:  
// SampleHandler for System.Dynamic.ExpandoObject event.  
Module Module1  

Sub Main()  
    Dim sampleObject As Object = New ExpandoObject()  

    ' Create a new event and initialize it with null.  
    sampleObject.sampleEvent = Nothing  

    ' Add an event handler.  
    Dim handler As EventHandler = AddressOf SampleHandler  
    sampleObject.sampleEvent =   
        [Delegate].Combine(sampleObject.sampleEvent, handler)  

    ' Raise an event for testing purposes.  
    sampleObject.sampleEvent.Invoke(sampleObject, New EventArgs())  

End Sub  

' Event handler.  
Sub SampleHandler(ByVal sender As Object, ByVal e As EventArgs)  
    Console.WriteLine("SampleHandler for {0} event", sender)  
End Sub  

' This code example produces the following output:  
' SampleHandler for System.Dynamic.ExpandoObject event.  

End Module  

Passing As a Parameter

You can pass instances of the ExpandoObject class as parameters. Note that these instances are treated as dynamic objects in C# and late-bound objects in Visual Basic. This means that you do not have IntelliSense for object members and you do not receive compiler errors when you call non-existent members. If you call a member that does not exist, an exception occurs.

The following code example demonstrates how you can create and use a method to print the names and values of properties.

class Program
{
    static void Main(string[] args)
    {
        dynamic employee, manager;

        employee = new ExpandoObject();
        employee.Name = "John Smith";
        employee.Age = 33;

        manager = new ExpandoObject();
        manager.Name = "Allison Brown";
        manager.Age = 42;
        manager.TeamSize = 10;

        WritePerson(manager);
        WritePerson(employee);
    }
    private static void WritePerson(dynamic person)
    {
        Console.WriteLine("{0} is {1} years old.",
                          person.Name, person.Age);
        // The following statement causes an exception
        // if you pass the employee object.
        // Console.WriteLine("Manages {0} people", person.TeamSize);
    }
}
// This code example produces the following output:
// John Smith is 33 years old.
// Allison Brown is 42 years old.
Sub Main()
    Dim employee, manager As Object

    employee = New ExpandoObject()
    employee.Name = "John Smith"
    employee.Age = 33

    manager = New ExpandoObject()
    manager.Name = "Allison Brown"
    manager.Age = 42
    manager.TeamSize = 10

    WritePerson(manager)
    WritePerson(employee)
End Sub

Private Sub WritePerson(ByVal person As Object)

    Console.WriteLine("{0} is {1} years old.",
                      person.Name, person.Age)
    ' The following statement causes an exception
    ' if you pass the employee object.
    ' Console.WriteLine("Manages {0} people", person.TeamSize)

End Sub

Enumerating and Deleting Members

The ExpandoObject class implements the IDictionary<String, Object> interface. This enables enumeration of members added to the instance of the ExpandoObject class at run time. This can be useful if you do not know at compile time what members an instance might have.

The following code example shows how you can cast an instance of the ExpandoObject class to the IDictionary<TKey,TValue> interface and enumerate the instance's members.

dynamic employee = new ExpandoObject();
employee.Name = "John Smith";
employee.Age = 33;

foreach (var property in (IDictionary<String, Object>)employee)
{
    Console.WriteLine(property.Key + ": " + property.Value);
}
// This code example produces the following output:
// Name: John Smith
// Age: 33
Dim employee As Object = New ExpandoObject()
employee.Name = "John Smith"
employee.Age = 33
For Each member In CType(employee, IDictionary(Of String, Object))
    Console.WriteLine(member.Key & ": " & member.Value)
Next
' This code example produces the following output:
' Name: John Smith
' Age: 33

In languages that do not have syntax for deleting members (such as C# and Visual Basic), you can delete a member by implicitly casting an instance of the ExpandoObject to the IDictionary<String, Object> interface and then deleting the member as a key/value pair. This is shown in the following example.

dynamic employee = new ExpandoObject();
employee.Name = "John Smith";
((IDictionary<String, Object>)employee).Remove("Name");
Dim employee As Object = New ExpandoObject()
employee.Name = "John Smith"
CType(employee, IDictionary(Of String, Object)).Remove("Name")

Receiving Notifications of Property Changes

The ExpandoObject class implements the INotifyPropertyChanged interface and can raise a PropertyChanged event when a member is added, deleted, or modified. This enables ExpandoObject class integration with Windows Presentation Foundation (WPF) data binding and other environments that require notification about changes in the object content.

The following code example demonstrates how to create an event handler for the PropertyChanged event.

// Add "using System.ComponentModel;" line
// to the beginning of the file.
class Program
{
    static void Test()
    {
        dynamic employee = new ExpandoObject();
        ((INotifyPropertyChanged)employee).PropertyChanged +=
            new PropertyChangedEventHandler(HandlePropertyChanges);
        employee.Name = "John Smith";
    }

    private static void HandlePropertyChanges(
        object sender, PropertyChangedEventArgs e)
    {
        Console.WriteLine("{0} has changed.", e.PropertyName);
    }
}
' Add "Imports System.ComponentModel" line 
' to the beginning of the file.
Sub Main()
    Dim employee As Object = New ExpandoObject
    AddHandler CType(
        employee, INotifyPropertyChanged).PropertyChanged,
        AddressOf HandlePropertyChanges
    employee.Name = "John Smith"
End Sub

Private Sub HandlePropertyChanges(
       ByVal sender As Object, ByVal e As PropertyChangedEventArgs)
    Console.WriteLine("{0} has changed.", e.PropertyName)
End Sub

Constructors

ExpandoObject()

Initializes a new ExpandoObject that does not have members.

Methods

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString()

Returns a string that represents the current object.

(Inherited from Object)

Explicit Interface Implementations

ICollection<KeyValuePair<String,Object>>.Add(KeyValuePair<String,Object>)

Adds the specified value to the ICollection<T> that has the specified key.

ICollection<KeyValuePair<String,Object>>.Clear()

Removes all items from the collection.

ICollection<KeyValuePair<String,Object>>.Contains(KeyValuePair<String,Object>)

Determines whether the ICollection<T> contains a specific key and value.

ICollection<KeyValuePair<String,Object>>.CopyTo(KeyValuePair<String,Object>[], Int32)

Copies the elements of the ICollection<T> to an array of type KeyValuePair<TKey,TValue>, starting at the specified array index.

ICollection<KeyValuePair<String,Object>>.Count

Gets the number of elements in the ICollection<T>.

ICollection<KeyValuePair<String,Object>>.IsReadOnly

Gets a value indicating whether the ICollection<T> is read-only.

ICollection<KeyValuePair<String,Object>>.Remove(KeyValuePair<String,Object>)

Removes a key and value from the collection.

IDictionary<String,Object>.Add(String, Object)

Adds the specified key and value to the dictionary.

IDictionary<String,Object>.ContainsKey(String)

Determines whether the dictionary contains the specified key.

IDictionary<String,Object>.Item[String]

Gets or sets the element that has the specified key.

IDictionary<String,Object>.Keys

Gets an ICollection<T> that contains the keys of the IDictionary<TKey,TValue>.

IDictionary<String,Object>.Remove(String)

Removes the element that has the specified key from the IDictionary.

IDictionary<String,Object>.TryGetValue(String, Object)

Gets the value associated with the specified key.

IDictionary<String,Object>.Values

Gets an ICollection<T> that contains the values in the IDictionary<TKey,TValue>.

IDynamicMetaObjectProvider.GetMetaObject(Expression)

The provided MetaObject will dispatch to the dynamic virtual methods. The object can be encapsulated inside another MetaObject to provide custom behavior for individual actions.

IEnumerable.GetEnumerator()

Returns an enumerator that iterates through the collection.

IEnumerable<KeyValuePair<String,Object>>.GetEnumerator()

Returns an enumerator that iterates through the collection.

INotifyPropertyChanged.PropertyChanged

Occurs when a property value changes.

Extension Methods

ToFrozenDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Creates a FrozenDictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector function.

ToFrozenDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

Creates a FrozenDictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

ToFrozenSet<T>(IEnumerable<T>, IEqualityComparer<T>)

Creates a FrozenSet<T> with the specified values.

AsReadOnly<TKey,TValue>(IDictionary<TKey,TValue>)

Returns a read-only ReadOnlyDictionary<TKey,TValue> wrapper for the current dictionary.

Remove<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue)

Tries to remove the value with the specified key from the dictionary.

TryAdd<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue)

Tries to add the specified key and value to the dictionary.

ToImmutableArray<TSource>(IEnumerable<TSource>)

Creates an immutable array from the specified collection.

ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Constructs an immutable dictionary from an existing collection of elements, applying a transformation function to the source keys.

ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Constructs an immutable dictionary based on some transformation of a sequence.

ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)

Enumerates and transforms a sequence, and produces an immutable dictionary of its contents.

ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>)

Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key comparer.

ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>, IEqualityComparer<TValue>)

Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key and value comparers.

ToImmutableHashSet<TSource>(IEnumerable<TSource>)

Enumerates a sequence and produces an immutable hash set of its contents.

ToImmutableHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)

Enumerates a sequence, produces an immutable hash set of its contents, and uses the specified equality comparer for the set type.

ToImmutableList<TSource>(IEnumerable<TSource>)

Enumerates a sequence and produces an immutable list of its contents.

ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)

Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents.

ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>)

Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key comparer.

ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>, IEqualityComparer<TValue>)

Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key and value comparers.

ToImmutableSortedSet<TSource>(IEnumerable<TSource>)

Enumerates a sequence and produces an immutable sorted set of its contents.

ToImmutableSortedSet<TSource>(IEnumerable<TSource>, IComparer<TSource>)

Enumerates a sequence, produces an immutable sorted set of its contents, and uses the specified comparer.

CopyToDataTable<T>(IEnumerable<T>)

Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)

Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)

Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>)

Applies an accumulator function over a sequence.

Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>)

Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.

Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>)

Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.

All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Determines whether all elements of a sequence satisfy a condition.

Any<TSource>(IEnumerable<TSource>)

Determines whether a sequence contains any elements.

Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Determines whether any element of a sequence satisfies a condition.

Append<TSource>(IEnumerable<TSource>, TSource)

Appends a value to the end of the sequence.

AsEnumerable<TSource>(IEnumerable<TSource>)

Returns the input typed as IEnumerable<T>.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.

Chunk<TSource>(IEnumerable<TSource>, Int32)

Splits the elements of a sequence into chunks of size at most size.

Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Concatenates two sequences.

Contains<TSource>(IEnumerable<TSource>, TSource)

Determines whether a sequence contains a specified element by using the default equality comparer.

Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)

Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.

Count<TSource>(IEnumerable<TSource>)

Returns the number of elements in a sequence.

Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns a number that represents how many elements in the specified sequence satisfy a condition.

DefaultIfEmpty<TSource>(IEnumerable<TSource>)

Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty.

DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource)

Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.

Distinct<TSource>(IEnumerable<TSource>)

Returns distinct elements from a sequence by using the default equality comparer to compare values.

Distinct<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)

Returns distinct elements from a sequence by using a specified IEqualityComparer<T> to compare values.

DistinctBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Returns distinct elements from a sequence according to a specified key selector function.

DistinctBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Returns distinct elements from a sequence according to a specified key selector function and using a specified comparer to compare keys.

ElementAt<TSource>(IEnumerable<TSource>, Index)

Returns the element at a specified index in a sequence.

ElementAt<TSource>(IEnumerable<TSource>, Int32)

Returns the element at a specified index in a sequence.

ElementAtOrDefault<TSource>(IEnumerable<TSource>, Index)

Returns the element at a specified index in a sequence or a default value if the index is out of range.

ElementAtOrDefault<TSource>(IEnumerable<TSource>, Int32)

Returns the element at a specified index in a sequence or a default value if the index is out of range.

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Produces the set difference of two sequences by using the default equality comparer to compare values.

Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.

ExceptBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)

Produces the set difference of two sequences according to a specified key selector function.

ExceptBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Produces the set difference of two sequences according to a specified key selector function.

First<TSource>(IEnumerable<TSource>)

Returns the first element of a sequence.

First<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the first element in a sequence that satisfies a specified condition.

FirstOrDefault<TSource>(IEnumerable<TSource>)

Returns the first element of a sequence, or a default value if the sequence contains no elements.

FirstOrDefault<TSource>(IEnumerable<TSource>, TSource)

Returns the first element of a sequence, or a specified default value if the sequence contains no elements.

FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.

FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)

Returns the first element of the sequence that satisfies a condition, or a specified default value if no such element is found.

GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Groups the elements of a sequence according to a specified key selector function.

GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.

GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function.

GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

Groups the elements of a sequence according to a key selector function. The keys are compared by using a comparer and each group's elements are projected by using a specified function.

GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>)

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.

GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>, IEqualityComparer<TKey>)

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The keys are compared by using a specified comparer.

GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>,TResult>)

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function.

GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource, TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>, TResult>, IEqualityComparer<TKey>)

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>, TResult>)

Correlates the elements of two sequences based on equality of keys and groups the results. The default equality comparer is used to compare keys.

GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>, TResult>, IEqualityComparer<TKey>)

Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer<T> is used to compare keys.

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Produces the set intersection of two sequences by using the default equality comparer to compare values.

Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.

IntersectBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)

Produces the set intersection of two sequences according to a specified key selector function.

IntersectBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Produces the set intersection of two sequences according to a specified key selector function.

Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>)

Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys.

Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>, IEqualityComparer<TKey>)

Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer<T> is used to compare keys.

Last<TSource>(IEnumerable<TSource>)

Returns the last element of a sequence.

Last<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the last element of a sequence that satisfies a specified condition.

LastOrDefault<TSource>(IEnumerable<TSource>)

Returns the last element of a sequence, or a default value if the sequence contains no elements.

LastOrDefault<TSource>(IEnumerable<TSource>, TSource)

Returns the last element of a sequence, or a specified default value if the sequence contains no elements.

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)

Returns the last element of a sequence that satisfies a condition, or a specified default value if no such element is found.

LongCount<TSource>(IEnumerable<TSource>)

Returns an Int64 that represents the total number of elements in a sequence.

LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns an Int64 that represents how many elements in a sequence satisfy a condition.

Max<TSource>(IEnumerable<TSource>)

Returns the maximum value in a generic sequence.

Max<TSource>(IEnumerable<TSource>, IComparer<TSource>)

Returns the maximum value in a generic sequence.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

Invokes a transform function on each element of a sequence and returns the maximum Decimal value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

Invokes a transform function on each element of a sequence and returns the maximum Double value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

Invokes a transform function on each element of a sequence and returns the maximum Int32 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

Invokes a transform function on each element of a sequence and returns the maximum Int64 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

Invokes a transform function on each element of a sequence and returns the maximum nullable Decimal value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

Invokes a transform function on each element of a sequence and returns the maximum nullable Double value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

Invokes a transform function on each element of a sequence and returns the maximum nullable Int32 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

Invokes a transform function on each element of a sequence and returns the maximum nullable Single value.

Max<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

Invokes a transform function on each element of a sequence and returns the maximum Single value.

Max<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

Invokes a transform function on each element of a generic sequence and returns the maximum resulting value.

MaxBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Returns the maximum value in a generic sequence according to a specified key selector function.

MaxBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

Returns the maximum value in a generic sequence according to a specified key selector function and key comparer.

Min<TSource>(IEnumerable<TSource>)

Returns the minimum value in a generic sequence.

Min<TSource>(IEnumerable<TSource>, IComparer<TSource>)

Returns the minimum value in a generic sequence.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

Invokes a transform function on each element of a sequence and returns the minimum Decimal value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

Invokes a transform function on each element of a sequence and returns the minimum Double value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

Invokes a transform function on each element of a sequence and returns the minimum Int32 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

Invokes a transform function on each element of a sequence and returns the minimum Int64 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

Invokes a transform function on each element of a sequence and returns the minimum nullable Decimal value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

Invokes a transform function on each element of a sequence and returns the minimum nullable Double value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

Invokes a transform function on each element of a sequence and returns the minimum nullable Int32 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

Invokes a transform function on each element of a sequence and returns the minimum nullable Int64 value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

Invokes a transform function on each element of a sequence and returns the minimum nullable Single value.

Min<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

Invokes a transform function on each element of a sequence and returns the minimum Single value.

Min<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

Invokes a transform function on each element of a generic sequence and returns the minimum resulting value.

MinBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Returns the minimum value in a generic sequence according to a specified key selector function.

MinBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

Returns the minimum value in a generic sequence according to a specified key selector function and key comparer.

OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.

Order<T>(IEnumerable<T>)

Sorts the elements of a sequence in ascending order.

Order<T>(IEnumerable<T>, IComparer<T>)

Sorts the elements of a sequence in ascending order.

OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Sorts the elements of a sequence in ascending order according to a key.

OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

Sorts the elements of a sequence in ascending order by using a specified comparer.

OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Sorts the elements of a sequence in descending order according to a key.

OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)

Sorts the elements of a sequence in descending order by using a specified comparer.

OrderDescending<T>(IEnumerable<T>)

Sorts the elements of a sequence in descending order.

OrderDescending<T>(IEnumerable<T>, IComparer<T>)

Sorts the elements of a sequence in descending order.

Prepend<TSource>(IEnumerable<TSource>, TSource)

Adds a value to the beginning of the sequence.

Reverse<TSource>(IEnumerable<TSource>)

Inverts the order of the elements in a sequence.

Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)

Projects each element of a sequence into a new form.

Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,TResult>)

Projects each element of a sequence into a new form by incorporating the element's index.

SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TResult>>)

Projects each element of a sequence to an IEnumerable<T> and flattens the resulting sequences into one sequence.

SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TResult>>)

Projects each element of a sequence to an IEnumerable<T>, and flattens the resulting sequences into one sequence. The index of each source element is used in the projected form of that element.

SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)

Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein.

SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)

Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. The index of each source element is used in the intermediate projected form of that element.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.

SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.

Single<TSource>(IEnumerable<TSource>)

Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.

Single<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

SingleOrDefault<TSource>(IEnumerable<TSource>)

Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

SingleOrDefault<TSource>(IEnumerable<TSource>, TSource)

Returns the only element of a sequence, or a specified default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)

Returns the only element of a sequence that satisfies a specified condition, or a specified default value if no such element exists; this method throws an exception if more than one element satisfies the condition.

Skip<TSource>(IEnumerable<TSource>, Int32)

Bypasses a specified number of elements in a sequence and then returns the remaining elements.

SkipLast<TSource>(IEnumerable<TSource>, Int32)

Returns a new enumerable collection that contains the elements from source with the last count elements of the source collection omitted.

SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.

SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. The element's index is used in the logic of the predicate function.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)

Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Double>)

Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)

Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)

Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)

Computes the sum of the sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)

Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)

Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)

Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)

Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.

Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)

Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.

Take<TSource>(IEnumerable<TSource>, Int32)

Returns a specified number of contiguous elements from the start of a sequence.

Take<TSource>(IEnumerable<TSource>, Range)

Returns a specified range of contiguous elements from a sequence.

TakeLast<TSource>(IEnumerable<TSource>, Int32)

Returns a new enumerable collection that contains the last count elements from source.

TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Returns elements from a sequence as long as a specified condition is true.

TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

Returns elements from a sequence as long as a specified condition is true. The element's index is used in the logic of the predicate function.

ToArray<TSource>(IEnumerable<TSource>)

Creates an array from a IEnumerable<T>.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

ToHashSet<TSource>(IEnumerable<TSource>)

Creates a HashSet<T> from an IEnumerable<T>.

ToHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)

Creates a HashSet<T> from an IEnumerable<T> using the comparer to compare keys.

ToList<TSource>(IEnumerable<TSource>)

Creates a List<T> from an IEnumerable<T>.

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function.

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function and key comparer.

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to specified key selector and element selector functions.

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function, a comparer and an element selector function.

TryGetNonEnumeratedCount<TSource>(IEnumerable<TSource>, Int32)

Attempts to determine the number of elements in a sequence without forcing an enumeration.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)

Produces the set union of two sequences by using the default equality comparer.

Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)

Produces the set union of two sequences by using a specified IEqualityComparer<T>.

UnionBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TSource>, Func<TSource,TKey>)

Produces the set union of two sequences according to a specified key selector function.

UnionBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

Produces the set union of two sequences according to a specified key selector function.

Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Filters a sequence of values based on a predicate.

Where<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)

Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function.

Zip<TFirst,TSecond>(IEnumerable<TFirst>, IEnumerable<TSecond>)

Produces a sequence of tuples with elements from the two specified sequences.

Zip<TFirst,TSecond,TThird>(IEnumerable<TFirst>, IEnumerable<TSecond>, IEnumerable<TThird>)

Produces a sequence of tuples with elements from the three specified sequences.

Zip<TFirst,TSecond,TResult>(IEnumerable<TFirst>, IEnumerable<TSecond>, Func<TFirst,TSecond,TResult>)

Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.

AsParallel(IEnumerable)

Enables parallelization of a query.

AsParallel<TSource>(IEnumerable<TSource>)

Enables parallelization of a query.

AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

AsQueryable<TElement>(IEnumerable<TElement>)

Converts a generic IEnumerable<T> to a generic IQueryable<T>.

Ancestors<T>(IEnumerable<T>)

Returns a collection of elements that contains the ancestors of every node in the source collection.

Ancestors<T>(IEnumerable<T>, XName)

Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.

DescendantNodes<T>(IEnumerable<T>)

Returns a collection of the descendant nodes of every document and element in the source collection.

Descendants<T>(IEnumerable<T>)

Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Descendants<T>(IEnumerable<T>, XName)

Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

Elements<T>(IEnumerable<T>)

Returns a collection of the child elements of every element and document in the source collection.

Elements<T>(IEnumerable<T>, XName)

Returns a filtered collection of the child elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

InDocumentOrder<T>(IEnumerable<T>)

Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.

Nodes<T>(IEnumerable<T>)

Returns a collection of the child nodes of every document and element in the source collection.

Remove<T>(IEnumerable<T>)

Removes every node in the source collection from its parent node.

Applies to