# C1.WPF.Extended.C1Expander.IsExpandedChanging

## Content

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<h1 id="C1_WPF_Extended_C1Expander_IsExpandedChanging" data-uid="C1.WPF.Extended.C1Expander.IsExpandedChanging" class="text-break">IsExpandedChanging Event
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<div class="markdown level0 summary"><p>Occurs before the <a class="xref" href="C1.WPF.Extended.C1Expander.html">C1Expander</a> is expanded.</p>
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<div class="markdown level0 conceptual"></div>
<h6><strong>Namespace</strong>: <a class="xref" href="C1.WPF.Extended.html">C1.WPF.Extended</a></h6>
<h6><strong>Assembly</strong>: C1.WPF.Extended.4.6.2.dll</h6>
<h5 id="C1_WPF_Extended_C1Expander_IsExpandedChanging_syntax">Syntax</h5>
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  <pre><code class="lang-csharp hljs">public event EventHandler&lt;PropertyChangingEventArgs&lt;bool&gt;&gt; IsExpandedChanging</code></pre>
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  <pre><code class="lang-vbnet hljs">Public Event IsExpandedChanging As EventHandler(Of PropertyChangingEventArgs(Of Boolean))</code></pre>
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<h5 class="returns">Returns</h5>
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      <th>Type</th>
      <th>Description</th>
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      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.eventhandler-1">EventHandler</a>&lt;<span class="xref">PropertyChangingEventArgs</span>&lt;<a class="xref" href="https://learn.microsoft.com/dotnet/api/system.boolean">bool</a>&gt;&gt;</td>
      <td>Occurs before the  is expanded.</td>
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