# GrapeCity.Spreadsheet.SparklineDataSource.OnDirtying

## Content

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<h1 id="GrapeCity_Spreadsheet_SparklineDataSource_OnDirtying_" data-uid="GrapeCity.Spreadsheet.SparklineDataSource.OnDirtying*">OnDirtying Method
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<div class="markdown level0 conceptual"></div>



<a id="GrapeCity_Spreadsheet_SparklineDataSource_OnDirtying_" data-uid="GrapeCity.Spreadsheet.SparklineDataSource.OnDirtying*"></a>
<h4 id="GrapeCity_Spreadsheet_SparklineDataSource_OnDirtying" data-uid="GrapeCity.Spreadsheet.SparklineDataSource.OnDirtying">OnDirtying()</h4>
<div class="markdown level1 summary"><p>Designates this external variable to be recalculated when the next recalculation occurs.</p>
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<h5 class="declaration">Declaration</h5>
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  <pre><code class="lang-csharp hljs">protected override bool OnDirtying()</code></pre>
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  <pre><code class="lang-vbnet hljs">Protected Overrides Function OnDirtying() As 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.boolean">bool</a></td>
      <td><p><code>true</code> if the external variable require executing its own logic after the calculation engine is ready; otherwise, <code>false</code>.</p>
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<h5 class="overrides">Overrides</h5>
<div><span class="xref">GrapeCity.Spreadsheet.Data.CellRangeDataSource&lt;double&gt;.OnDirtying()</span></div>
<h5 id="GrapeCity_Spreadsheet_SparklineDataSource_OnDirtying_remarks">Remarks</h5>
<div class="markdown level1 remarks"><p>Accessing calculation engine (like get value of external variable) isn't available inside this function.</p>
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