# C1.Document.INotifyCollection.CollectionChanging

## Content

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




<h1 id="C1_Document_INotifyCollection_CollectionChanging" data-uid="C1.Document.INotifyCollection.CollectionChanging" class="text-break">CollectionChanging Event
</h1>
<div class="markdown level0 summary"><p>Occurs when a collection about to be changed.</p>
</div>
<div class="markdown level0 conceptual"></div>
<h6><strong>Namespace</strong>: <a class="xref" href="C1.Document.html">C1.Document</a></h6>
<h6><strong>Assembly</strong>: C1.Document.dll</h6>
<h5 id="C1_Document_INotifyCollection_CollectionChanging_syntax">Syntax</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">event NotifyCollectionEventHandler CollectionChanging</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Event CollectionChanging As NotifyCollectionEventHandler</code></pre>
</div>
<h5 class="returns">Returns</h5>
<table class="table table-bordered table-condensed">
  <thead>
    <tr>
      <th>Type</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a class="xref" href="C1.Document.NotifyCollectionEventHandler.html">NotifyCollectionEventHandler</a></td>
      <td>Occurs when a collection about to be changed.</td>
    </tr>
  </tbody>
</table>
</div>