CollectionBase.xml

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    <summary>Provides the <see langword="abstract" /> base class for a strongly typed collection.</summary>
    <remarks>
      <format type="text/markdown"><![CDATA[

## Remarks

> [!IMPORTANT]
>  We don't recommend that you use the `CollectionBase` class for new development. Instead, we recommend that you use the generic <xref:System.Collections.ObjectModel.Collection`1> class. For more information, see [Non-generic collections shouldn't be used](https://github.com/dotnet/platform-compat/blob/master/docs/DE0006.md) on GitHub.

A <xref:System.Collections.CollectionBase> instance is always modifiable. See <xref:System.Collections.ReadOnlyCollectionBase> for a read-only version of this class.

 The capacity of a <xref:System.Collections.CollectionBase> is the number of elements the <xref:System.Collections.CollectionBase> can hold. As elements are added to a <xref:System.Collections.CollectionBase>, the capacity is automatically increased as required through reallocation. The capacity can be decreased by setting the <xref:System.Collections.CollectionBase.Capacity> property explicitly.



## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
    </remarks>
    <threadsafe>Public static (<see langword="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 <see cref="T:System.Collections.CollectionBase" />, but derived classes can create their own synchronized versions of the <see cref="T:System.Collections.CollectionBase" /> using the <see cref="P:System.Collections.ICollection.SyncRoot" /> property.

 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.</threadsafe>
    <block subset="none" type="overrides">
      <para>This base class is provided to make it easier for implementers to create a strongly typed custom collection. Implementers are encouraged to extend this base class instead of creating their own.</para>
    </block>
    <altmember cref="T:System.Collections.ArrayList" />
    <altmember cref="T:System.Collections.IList" />
    <altmember cref="T:System.Collections.ReadOnlyCollectionBase" />
    <altmember cref="N:System.Collections.Generic" />
    <related type="Article" href="/dotnet/standard/globalization-localization/performing-culture-insensitive-string-operations">Performing Culture-Insensitive String Operations</related>
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        <summary>Initializes a new instance of the <see cref="T:System.Collections.CollectionBase" /> class.</summary>
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        <summary>Initializes a new instance of the <see cref="T:System.Collections.CollectionBase" /> class with the default initial capacity.</summary>
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          <format type="text/markdown"><![CDATA[

## Remarks
 The capacity of a <xref:System.Collections.CollectionBase> is the number of elements that the <xref:System.Collections.CollectionBase> can hold. As elements are added to a <xref:System.Collections.CollectionBase>, the capacity is automatically increased as required by reallocating the internal array.

 If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the <xref:System.Collections.CollectionBase>.

 This constructor is an `O(1)` operation.

 ]]></format>
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        <param name="capacity">The number of elements that the new list can initially store.</param>
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        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The capacity of a <xref:System.Collections.CollectionBase> is the number of elements that the <xref:System.Collections.CollectionBase> can hold. As elements are added to a <xref:System.Collections.CollectionBase>, the capacity is automatically increased as required by reallocating the internal array.

 If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the <xref:System.Collections.CollectionBase>.

 This constructor is an `O(n)` operation, where `n` is `capacity`.

 ]]></format>
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        <summary>Gets or sets the number of elements that the <see cref="T:System.Collections.CollectionBase" /> can contain.</summary>
        <value>The number of elements that the <see cref="T:System.Collections.CollectionBase" /> can contain.</value>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 <xref:System.Collections.CollectionBase.Capacity*> is the number of elements that the <xref:System.Collections.CollectionBase> can store. <xref:System.Collections.CollectionBase.Count*> is the number of elements that are actually in the <xref:System.Collections.CollectionBase>.

 <xref:System.Collections.CollectionBase.Capacity*> is always greater than or equal to <xref:System.Collections.CollectionBase.Count*>. If <xref:System.Collections.CollectionBase.Count*> exceeds <xref:System.Collections.CollectionBase.Capacity*> while adding elements, the capacity is automatically increased by reallocating the internal array before copying the old elements and adding the new elements.

 The capacity can be decreased by setting the <xref:System.Collections.CollectionBase.Capacity> property explicitly. When the value of <xref:System.Collections.CollectionBase.Capacity*> is set explicitly, the internal array is also reallocated to accommodate the specified capacity.

 Retrieving the value of this property is an `O(1)` operation; setting the property is an `O(n)` operation, where `n` is the new capacity.

 ]]></format>
        </remarks>
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          <see cref="P:System.Collections.CollectionBase.Capacity" /> is set to a value that is less than <see cref="P:System.Collections.CollectionBase.Count" />.</exception>
        <exception cref="T:System.OutOfMemoryException">There is not enough memory available on the system.</exception>
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        <summary>Removes all objects from the <see cref="T:System.Collections.CollectionBase" /> instance. This method cannot be overridden.</summary>
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## Remarks
 <xref:System.Collections.CollectionBase.Count*> is set to zero.

 This method is an `O(n)` operation, where `n` is <xref:System.Collections.CollectionBase.Count*>.

 To perform custom actions before or after the collection is cleared, override the protected <xref:System.Collections.CollectionBase.OnClear*> or <xref:System.Collections.CollectionBase.OnClearComplete*> method.

 ]]></format>
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        <summary>Gets the number of elements contained in the <see cref="T:System.Collections.CollectionBase" /> instance. This property cannot be overridden.</summary>
        <value>The number of elements contained in the <see cref="T:System.Collections.CollectionBase" /> instance. Retrieving the value of this property is an O(1) operation.</value>
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          <format type="text/markdown"><![CDATA[

## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="GetEnumerator">
      <MemberSignature Language="C#" Value="public System.Collections.IEnumerator GetEnumerator ();" />
      <MemberSignature Language="ILAsm" Value=".method public hidebysig newslot virtual instance class System.Collections.IEnumerator GetEnumerator() cil managed" />
      <MemberSignature Language="DocId" Value="M:System.Collections.CollectionBase.GetEnumerator" />
      <MemberSignature Language="VB.NET" Value="Public Function GetEnumerator () As IEnumerator" />
      <MemberSignature Language="F#" Value="abstract member GetEnumerator : unit -&gt; System.Collections.IEnumerator&#xA;override this.GetEnumerator : unit -&gt; System.Collections.IEnumerator" Usage="collectionBase.GetEnumerator " />
      <MemberSignature Language="C++ CLI" Value="public:&#xA; virtual System::Collections::IEnumerator ^ GetEnumerator();" />
      <MemberType>Method</MemberType>
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        <InterfaceMember>M:System.Collections.IEnumerable.GetEnumerator</InterfaceMember>
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        <AssemblyName>System.Collections.NonGeneric</AssemblyName>
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        <AssemblyVersion>4.0.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.0.0</AssemblyVersion>
        <AssemblyVersion>4.1.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.2.0</AssemblyVersion>
        <AssemblyVersion>5.0.0.0</AssemblyVersion>
        <AssemblyVersion>6.0.0.0</AssemblyVersion>
        <AssemblyVersion>7.0.0.0</AssemblyVersion>
        <AssemblyVersion>8.0.0.0</AssemblyVersion>
        <AssemblyVersion>9.0.0.0</AssemblyVersion>
        <AssemblyVersion>10.0.0.0</AssemblyVersion>
        <AssemblyVersion>11.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>mscorlib</AssemblyName>
        <AssemblyVersion>1.0.5000.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.5.0</AssemblyVersion>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>netstandard</AssemblyName>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.1.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Collections.IEnumerator</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Returns an enumerator that iterates through the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <returns>An <see cref="T:System.Collections.IEnumerator" /> for the <see cref="T:System.Collections.CollectionBase" /> instance.</returns>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks

 The `foreach` statement of the C# language (`for each` in Visual Basic) hides the complexity of the enumerators.  Therefore, using `foreach` is recommended, instead of directly manipulating the enumerator.

 Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.

 Initially, the enumerator is positioned before the first element in the collection. <xref:System.Collections.IEnumerator.Reset*> also brings the enumerator back to this position. At this position, calling <xref:System.Collections.IEnumerator.Current*> throws an exception. Therefore, you must call <xref:System.Collections.IEnumerator.MoveNext*> to advance the enumerator to the first element of the collection before reading the value of <xref:System.Collections.IEnumerator.Current*>.

 <xref:System.Collections.IEnumerator.Current*> returns the same object until either <xref:System.Collections.IEnumerator.MoveNext*> or <xref:System.Collections.IEnumerator.Reset*> is called. <xref:System.Collections.IEnumerator.MoveNext*> sets <xref:System.Collections.IEnumerator.Current*> to the next element.

 If <xref:System.Collections.IEnumerator.MoveNext*> passes the end of the collection, the enumerator is positioned after the last element in the collection and <xref:System.Collections.IEnumerator.MoveNext*> returns `false`. When the enumerator is at this position, subsequent calls to <xref:System.Collections.IEnumerator.MoveNext*> also return `false`. If the last call to <xref:System.Collections.IEnumerator.MoveNext*> returned `false`, calling <xref:System.Collections.IEnumerator.Current*> throws an exception. To set <xref:System.Collections.IEnumerator.Current*> to the first element of the collection again, you can call <xref:System.Collections.IEnumerator.Reset*> followed by <xref:System.Collections.IEnumerator.MoveNext*>.

 An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and the next call to <xref:System.Collections.IEnumerator.MoveNext*> or <xref:System.Collections.IEnumerator.Reset*> throws an <xref:System.InvalidOperationException>. If the collection is modified between <xref:System.Collections.IEnumerator.MoveNext*> and <xref:System.Collections.IEnumerator.Current*>, <xref:System.Collections.IEnumerator.Current*> returns the element that it is set to, even if the enumerator is already invalidated.

 The enumerator does not have exclusive access to the collection; therefore, 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.

 While the <xref:System.Collections.CollectionBase.GetEnumerator*> method is not visible to COM clients by default, inheriting the <xref:System.Collections.CollectionBase> class can expose it and can cause undesirable behavior in COM clients.

 This method is an `O(1)` operation.



## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
        </remarks>
        <altmember cref="T:System.Collections.IEnumerator" />
      </Docs>
    </Member>
    <Member MemberName="InnerList">
      <MemberSignature Language="C#" Value="protected System.Collections.ArrayList InnerList { get; }" />
      <MemberSignature Language="ILAsm" Value=".property instance class System.Collections.ArrayList InnerList" />
      <MemberSignature Language="DocId" Value="P:System.Collections.CollectionBase.InnerList" />
      <MemberSignature Language="VB.NET" Value="Protected ReadOnly Property InnerList As ArrayList" />
      <MemberSignature Language="F#" Value="member this.InnerList : System.Collections.ArrayList" Usage="System.Collections.CollectionBase.InnerList" />
      <MemberSignature Language="C++ CLI" Value="protected:&#xA; property System::Collections::ArrayList ^ InnerList { System::Collections::ArrayList ^ get(); };" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyName>System.Collections.NonGeneric</AssemblyName>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
        <AssemblyVersion>4.0.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.0.0</AssemblyVersion>
        <AssemblyVersion>4.1.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.2.0</AssemblyVersion>
        <AssemblyVersion>5.0.0.0</AssemblyVersion>
        <AssemblyVersion>6.0.0.0</AssemblyVersion>
        <AssemblyVersion>7.0.0.0</AssemblyVersion>
        <AssemblyVersion>8.0.0.0</AssemblyVersion>
        <AssemblyVersion>9.0.0.0</AssemblyVersion>
        <AssemblyVersion>10.0.0.0</AssemblyVersion>
        <AssemblyVersion>11.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>mscorlib</AssemblyName>
        <AssemblyVersion>1.0.5000.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.5.0</AssemblyVersion>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>netstandard</AssemblyName>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.1.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Collections.ArrayList</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets an <see cref="T:System.Collections.ArrayList" /> containing the list of elements in the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <value>An <see cref="T:System.Collections.ArrayList" /> representing the <see cref="T:System.Collections.CollectionBase" /> instance itself. Retrieving the value of this property is an O(1) operation.</value>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 ]]></format>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="List">
      <MemberSignature Language="C#" Value="protected System.Collections.IList List { get; }" />
      <MemberSignature Language="ILAsm" Value=".property instance class System.Collections.IList List" />
      <MemberSignature Language="DocId" Value="P:System.Collections.CollectionBase.List" />
      <MemberSignature Language="VB.NET" Value="Protected ReadOnly Property List As IList" />
      <MemberSignature Language="F#" Value="member this.List : System.Collections.IList" Usage="System.Collections.CollectionBase.List" />
      <MemberSignature Language="C++ CLI" Value="protected:&#xA; property System::Collections::IList ^ List { System::Collections::IList ^ get(); };" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyName>System.Collections.NonGeneric</AssemblyName>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
        <AssemblyVersion>4.0.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.0.0</AssemblyVersion>
        <AssemblyVersion>4.1.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.2.0</AssemblyVersion>
        <AssemblyVersion>5.0.0.0</AssemblyVersion>
        <AssemblyVersion>6.0.0.0</AssemblyVersion>
        <AssemblyVersion>7.0.0.0</AssemblyVersion>
        <AssemblyVersion>8.0.0.0</AssemblyVersion>
        <AssemblyVersion>9.0.0.0</AssemblyVersion>
        <AssemblyVersion>10.0.0.0</AssemblyVersion>
        <AssemblyVersion>11.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>mscorlib</AssemblyName>
        <AssemblyVersion>1.0.5000.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.5.0</AssemblyVersion>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>netstandard</AssemblyName>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.1.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Collections.IList</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets an <see cref="T:System.Collections.IList" /> containing the list of elements in the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <value>An <see cref="T:System.Collections.IList" /> representing the <see cref="T:System.Collections.CollectionBase" /> instance itself.</value>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 Retrieving the value of this property is an `O(1)` operation.



## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="OnClear">
      <MemberSignature Language="C#" Value="protected virtual void OnClear ();" />
      <MemberSignature Language="ILAsm" Value=".method familyhidebysig newslot virtual instance void OnClear() cil managed" />
      <MemberSignature Language="DocId" Value="M:System.Collections.CollectionBase.OnClear" />
      <MemberSignature Language="VB.NET" Value="Protected Overridable Sub OnClear ()" />
      <MemberSignature Language="F#" Value="abstract member OnClear : unit -&gt; unit&#xA;override this.OnClear : unit -&gt; unit" Usage="collectionBase.OnClear " />
      <MemberSignature Language="C++ CLI" Value="protected:&#xA; virtual void OnClear();" />
      <MemberType>Method</MemberType>
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        <AssemblyVersion>4.0.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.0.0</AssemblyVersion>
        <AssemblyVersion>4.1.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.2.0</AssemblyVersion>
        <AssemblyVersion>5.0.0.0</AssemblyVersion>
        <AssemblyVersion>6.0.0.0</AssemblyVersion>
        <AssemblyVersion>7.0.0.0</AssemblyVersion>
        <AssemblyVersion>8.0.0.0</AssemblyVersion>
        <AssemblyVersion>9.0.0.0</AssemblyVersion>
        <AssemblyVersion>10.0.0.0</AssemblyVersion>
        <AssemblyVersion>11.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>mscorlib</AssemblyName>
        <AssemblyVersion>1.0.5000.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.5.0</AssemblyVersion>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>netstandard</AssemblyName>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.1.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Performs additional custom processes when clearing the contents of the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The default implementation of this method is intended to be overridden by a derived class to perform some action before the collection is cleared.

 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 If the process fails, the collection reverts back to its previous state.

 The default implementation of this method is an `O(1)` operation.

 ]]></format>
        </remarks>
        <block subset="none" type="overrides">
          <para>This method allows implementers to define processes that must be performed before deleting all the elements from the underlying <see cref="T:System.Collections.ArrayList" />. By defining this method, implementers can add functionality to inherited methods without having to override all other methods.

 <see cref="M:System.Collections.CollectionBase.OnClear" /> is invoked before the standard Clear behavior, whereas <see cref="M:System.Collections.CollectionBase.OnClearComplete" /> is invoked after the standard Clear behavior.

 For example, implementers can exempt certain elements from deletion by a global Clear.</para>
        </block>
        <altmember cref="M:System.Collections.CollectionBase.OnClearComplete" />
        <altmember cref="M:System.Collections.CollectionBase.OnRemove(System.Int32,System.Object)" />
      </Docs>
    </Member>
    <Member MemberName="OnClearComplete">
      <MemberSignature Language="C#" Value="protected virtual void OnClearComplete ();" />
      <MemberSignature Language="ILAsm" Value=".method familyhidebysig newslot virtual instance void OnClearComplete() cil managed" />
      <MemberSignature Language="DocId" Value="M:System.Collections.CollectionBase.OnClearComplete" />
      <MemberSignature Language="VB.NET" Value="Protected Overridable Sub OnClearComplete ()" />
      <MemberSignature Language="F#" Value="abstract member OnClearComplete : unit -&gt; unit&#xA;override this.OnClearComplete : unit -&gt; unit" Usage="collectionBase.OnClearComplete " />
      <MemberSignature Language="C++ CLI" Value="protected:&#xA; virtual void OnClearComplete();" />
      <MemberType>Method</MemberType>
      <AssemblyInfo>
        <AssemblyName>System.Collections.NonGeneric</AssemblyName>
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        <AssemblyVersion>4.0.1.0</AssemblyVersion>
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        <AssemblyVersion>4.1.1.0</AssemblyVersion>
        <AssemblyVersion>4.1.2.0</AssemblyVersion>
        <AssemblyVersion>5.0.0.0</AssemblyVersion>
        <AssemblyVersion>6.0.0.0</AssemblyVersion>
        <AssemblyVersion>7.0.0.0</AssemblyVersion>
        <AssemblyVersion>8.0.0.0</AssemblyVersion>
        <AssemblyVersion>9.0.0.0</AssemblyVersion>
        <AssemblyVersion>10.0.0.0</AssemblyVersion>
        <AssemblyVersion>11.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>mscorlib</AssemblyName>
        <AssemblyVersion>1.0.5000.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.5.0</AssemblyVersion>
        <AssemblyVersion>4.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <AssemblyInfo>
        <AssemblyName>netstandard</AssemblyName>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
        <AssemblyVersion>2.1.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Performs additional custom processes after clearing the contents of the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The default implementation of this method is intended to be overridden by a derived class to perform some action after the collection is cleared.

 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 The default implementation of this method is an `O(1)` operation.

 ]]></format>
        </remarks>
        <block subset="none" type="overrides">
          <para>This method allows implementers to define processes that must be performed after deleting all the elements from the underlying <see cref="T:System.Collections.ArrayList" />. By defining this method, implementers can add functionality to inherited methods without having to override all other methods.

 <see cref="M:System.Collections.CollectionBase.OnClear" /> is invoked before the standard Clear behavior, whereas <see cref="M:System.Collections.CollectionBase.OnClearComplete" /> is invoked after the standard Clear behavior.</para>
        </block>
        <altmember cref="M:System.Collections.CollectionBase.OnClear" />
        <altmember cref="M:System.Collections.CollectionBase.OnRemoveComplete(System.Int32,System.Object)" />
      </Docs>
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    <Member MemberName="OnInsert">
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      <MemberSignature Language="C#" Value="protected virtual void OnInsert (int index, object? value);" FrameworkAlternate="net-10.0;net-11.0;net-5.0;net-6.0;net-7.0;net-8.0;net-9.0" />
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        <AssemblyVersion>4.0.0.0</AssemblyVersion>
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      <AssemblyInfo>
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      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
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      <Parameters>
        <Parameter Name="index" Type="System.Int32" />
        <Parameter Name="value" Type="System.Object" />
      </Parameters>
      <Docs>
        <param name="index">The zero-based index at which to insert <paramref name="value" />.</param>
        <param name="value">The new value of the element at <paramref name="index" />.</param>
        <summary>Performs additional custom processes before inserting a new element into the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The default implementation of this method is intended to be overridden by a derived class to perform some action before the specified element is inserted.

 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 If the process fails, the collection reverts back to its previous state.

 The default implementation of this method is an `O(1)` operation.



## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
        </remarks>
        <block subset="none" type="overrides">
          <para>This method allows implementers to define processes that must be performed before inserting the element into the underlying <see cref="T:System.Collections.ArrayList" />. By defining this method, implementers can add functionality to inherited methods without having to override all other methods.

 <see cref="M:System.Collections.CollectionBase.OnInsert(System.Int32,System.Object)" /> is invoked before the standard Insert behavior, whereas <see cref="M:System.Collections.CollectionBase.OnInsertComplete(System.Int32,System.Object)" /> is invoked after the standard Insert behavior.

 For example, implementers can restrict which types of objects can be inserted into the <see cref="T:System.Collections.ArrayList" />.

 <see cref="M:System.Collections.CollectionBase.OnValidate(System.Object)" /> is called prior to this method.</para>
        </block>
        <altmember cref="M:System.Collections.CollectionBase.OnInsertComplete(System.Int32,System.Object)" />
        <altmember cref="M:System.Collections.CollectionBase.OnSet(System.Int32,System.Object,System.Object)" />
        <altmember cref="M:System.Collections.CollectionBase.OnValidate(System.Object)" />
      </Docs>
    </Member>
    <Member MemberName="OnInsertComplete">
      <MemberSignature Language="C#" Value="protected virtual void OnInsertComplete (int index, object value);" FrameworkAlternate="dotnet-uwp-10.0;netcore-1.0;netcore-1.1;netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0;netcore-3.1;netframework-1.1;netframework-2.0;netframework-3.0;netframework-3.5;netframework-4.0;netframework-4.5;netframework-4.5.1;netframework-4.5.2;netframework-4.6;netframework-4.6.1;netframework-4.6.2;netframework-4.7;netframework-4.7.1;netframework-4.7.2;netframework-4.8;netframework-4.8.1;netstandard-2.0;netstandard-2.1" />
      <MemberSignature Language="ILAsm" Value=".method familyhidebysig newslot virtual instance void OnInsertComplete(int32 index, object value) cil managed" />
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      <MemberSignature Language="VB.NET" Value="Protected Overridable Sub OnInsertComplete (index As Integer, value As Object)" />
      <MemberSignature Language="F#" Value="abstract member OnInsertComplete : int * obj -&gt; unit&#xA;override this.OnInsertComplete : int * obj -&gt; unit" Usage="collectionBase.OnInsertComplete (index, value)" />
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        <Parameter Name="index" Type="System.Int32" />
        <Parameter Name="value" Type="System.Object" />
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        <param name="index">The zero-based index at which to insert <paramref name="value" />.</param>
        <param name="value">The new value of the element at <paramref name="index" />.</param>
        <summary>Performs additional custom processes after inserting a new element into the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
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          <format type="text/markdown"><![CDATA[

## Remarks
 The default implementation of this method is intended to be overridden by a derived class to perform some action after the specified element is inserted.

 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 The collection reverts back to its previous state if one of the following occurs:

- The process fails.

- This method is overridden to throw an exception.

 The default implementation of this method is an `O(1)` operation.

 ]]></format>
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          <para>This method allows implementers to define processes that must be performed after inserting the element into the underlying <see cref="T:System.Collections.ArrayList" />. By defining this method, implementers can add functionality to inherited methods without having to override all other methods.

 <see cref="M:System.Collections.CollectionBase.OnInsert(System.Int32,System.Object)" /> is invoked before the standard Insert behavior, whereas <see cref="M:System.Collections.CollectionBase.OnInsertComplete(System.Int32,System.Object)" /> is invoked after the standard Insert behavior.</para>
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        <param name="index">The zero-based index at which <paramref name="value" /> can be found.</param>
        <param name="value">The value of the element to remove from <paramref name="index" />.</param>
        <summary>Performs additional custom processes when removing an element from the <see cref="T:System.Collections.CollectionBase" /> instance.</summary>
        <remarks>
          <format type="text/markdown"><![CDATA[

## Remarks
 The default implementation of this method is intended to be overridden by a derived class to perform some action before the specified element is removed.

 The On* methods are invoked only on the instance returned by the <xref:System.Collections.CollectionBase.List> property, but not on the instance returned by the <xref:System.Collections.CollectionBase.InnerList> property.

 If the process fails, the collection reverts back to its previous state.

 The default implementation of this method is an `O(1)` operation.



## Examples
 The following code example implements the <xref:System.Collections.CollectionBase> class and uses that implementation to create a collection of <xref:System.Int16> objects.

 :::code language="csharp" source="~/snippets/csharp/System.Collections/CollectionBase/Overview/collectionbase.cs" id="Snippet1":::
 :::code language="vb" source="~/snippets/visualbasic/System.Collections/CollectionBase/Overview/collectionbase.vb" id="Snippet1":::

 ]]></format>
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 <see cref="M:System.Collections.CollectionBase.OnRemove(System.Int32,System.Object)" /> is invoked before the standard Remove behavior, whereas <see cref="M:System.Collections.CollectionBase.OnRemoveComplete(System.Int32,System.Object)" /> is invoked after the standard Remove behavior.

 For example, implementers can prevent removal of elements by always throwing an exception in <see cref="M:System.Collections.CollectionBase.OnRemove(System.Int32,System.Object)" />.

 <see cref="M:System.Collections.CollectionBase.OnValidate(System.Object)" /> is called prior to this method.</para>
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