# C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged

## Content

<div class="doc-site-dotnet-api-container">



<h1 id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged*">OnCollectionChanged Method
</h1>
<div class="markdown level0 summary"></div>
<div class="markdown level0 conceptual"></div>



<a id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged*"></a>
<h4 id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_System_Collections_Specialized_NotifyCollectionChangedEventArgs_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged(System.Collections.Specialized.NotifyCollectionChangedEventArgs)">OnCollectionChanged(NotifyCollectionChangedEventArgs)</h4>
<div class="markdown level1 summary"><p>Fires the CollectionChanged event.</p>
</div>
<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Protected Sub OnCollectionChanged(e As NotifyCollectionChangedEventArgs)</code></pre>
</div>
<h5 class="parameters">Parameters</h5>
<table class="table table-bordered table-condensed">
  <thead>
    <tr>
      <th>Type</th>
      <th>Name</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedeventargs">NotifyCollectionChangedEventArgs</a></td>
      <td><span class="parametername">e</span></td>
      <td></td>
    </tr>
  </tbody>
</table>


<a id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged*"></a>
<h4 id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_System_Collections_Specialized_NotifyCollectionChangedAction_System_Object_System_Int32_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged(System.Collections.Specialized.NotifyCollectionChangedAction,System.Object,System.Int32)">OnCollectionChanged(NotifyCollectionChangedAction, object, int)</h4>
<div class="markdown level1 summary"><p>Fires the CollectionChanged event.</p>
</div>
<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">protected void OnCollectionChanged(NotifyCollectionChangedAction action, object item, int index)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Protected Sub OnCollectionChanged(action As NotifyCollectionChangedAction, item As Object, index As Integer)</code></pre>
</div>
<h5 class="parameters">Parameters</h5>
<table class="table table-bordered table-condensed">
  <thead>
    <tr>
      <th>Type</th>
      <th>Name</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedaction">NotifyCollectionChangedAction</a></td>
      <td><span class="parametername">action</span></td>
      <td></td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.object">object</a></td>
      <td><span class="parametername">item</span></td>
      <td></td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.int32">int</a></td>
      <td><span class="parametername">index</span></td>
      <td></td>
    </tr>
  </tbody>
</table>


<a id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged*"></a>
<h4 id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_System_Collections_Specialized_NotifyCollectionChangedAction_System_Collections_Generic_IEnumerable_System_Object__" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged(System.Collections.Specialized.NotifyCollectionChangedAction,System.Collections.Generic.IEnumerable{System.Object})">OnCollectionChanged(NotifyCollectionChangedAction, IEnumerable&lt;object&gt;)</h4>
<div class="markdown level1 summary"><p>Fires the CollectionChanged event.</p>
</div>
<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">protected void OnCollectionChanged(NotifyCollectionChangedAction action, IEnumerable&lt;object&gt; items)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Protected Sub OnCollectionChanged(action As NotifyCollectionChangedAction, items As IEnumerable(Of Object))</code></pre>
</div>
<h5 class="parameters">Parameters</h5>
<table class="table table-bordered table-condensed">
  <thead>
    <tr>
      <th>Type</th>
      <th>Name</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedaction">NotifyCollectionChangedAction</a></td>
      <td><span class="parametername">action</span></td>
      <td></td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1">IEnumerable</a>&lt;<a class="xref" href="https://learn.microsoft.com/dotnet/api/system.object">object</a>&gt;</td>
      <td><span class="parametername">items</span></td>
      <td></td>
    </tr>
  </tbody>
</table>


<a id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged*"></a>
<h4 id="C1_Win_C1Input_ComboBoxItemList_OnCollectionChanged_System_Collections_Specialized_NotifyCollectionChangedAction_System_Collections_Generic_IEnumerable_System_Object__System_Int32_" data-uid="C1.Win.C1Input.ComboBoxItemList.OnCollectionChanged(System.Collections.Specialized.NotifyCollectionChangedAction,System.Collections.Generic.IEnumerable{System.Object},System.Int32)">OnCollectionChanged(NotifyCollectionChangedAction, IEnumerable&lt;object&gt;, int)</h4>
<div class="markdown level1 summary"><p>Fires the CollectionChanged event.</p>
</div>
<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">protected void OnCollectionChanged(NotifyCollectionChangedAction action, IEnumerable&lt;object&gt; items, int index)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Protected Sub OnCollectionChanged(action As NotifyCollectionChangedAction, items As IEnumerable(Of Object), index As Integer)</code></pre>
</div>
<h5 class="parameters">Parameters</h5>
<table class="table table-bordered table-condensed">
  <thead>
    <tr>
      <th>Type</th>
      <th>Name</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedaction">NotifyCollectionChangedAction</a></td>
      <td><span class="parametername">action</span></td>
      <td></td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1">IEnumerable</a>&lt;<a class="xref" href="https://learn.microsoft.com/dotnet/api/system.object">object</a>&gt;</td>
      <td><span class="parametername">items</span></td>
      <td></td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.int32">int</a></td>
      <td><span class="parametername">index</span></td>
      <td></td>
    </tr>
  </tbody>
</table>
</div>