# C1.CalcEngine.ExpressionEngine.ExpressionEngine.GetFunctionExpression

## Content

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<h1 id="C1_CalcEngine_ExpressionEngine_ExpressionEngine_GetFunctionExpression_" data-uid="C1.CalcEngine.ExpressionEngine.ExpressionEngine.GetFunctionExpression*">GetFunctionExpression Method
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<div class="markdown level0 conceptual"></div>



<a id="C1_CalcEngine_ExpressionEngine_ExpressionEngine_GetFunctionExpression_" data-uid="C1.CalcEngine.ExpressionEngine.ExpressionEngine.GetFunctionExpression*"></a>
<h4 id="C1_CalcEngine_ExpressionEngine_ExpressionEngine_GetFunctionExpression_System_String_C1_CalcEngine_ExpressionEngine_FunctionDefinition_System_Collections_Generic_List_C1_CalcEngine_ExpressionEngine_IExpression__" data-uid="C1.CalcEngine.ExpressionEngine.ExpressionEngine.GetFunctionExpression(System.String,C1.CalcEngine.ExpressionEngine.FunctionDefinition,System.Collections.Generic.List{C1.CalcEngine.ExpressionEngine.IExpression})">GetFunctionExpression(string, FunctionDefinition, List&lt;IExpression&gt;)</h4>
<div class="markdown level1 summary"><p>Gets a function expression.</p>
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<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
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  <pre><code class="lang-csharp hljs">protected virtual IExpression GetFunctionExpression(string id, FunctionDefinition fnDef, List&lt;IExpression&gt; expr)</code></pre>
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  <pre><code class="lang-vbnet hljs">Protected Overridable Function GetFunctionExpression(id As String, fnDef As FunctionDefinition, expr As List(Of IExpression)) As IExpression</code></pre>
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<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.string">string</a></td>
      <td><span class="parametername">id</span></td>
      <td><p>Function identifier.</p>
</td>
    </tr>
    <tr>
      <td><a class="xref" href="C1.CalcEngine.ExpressionEngine.FunctionDefinition.html">FunctionDefinition</a></td>
      <td><span class="parametername">fnDef</span></td>
      <td><p>Function definition.</p>
</td>
    </tr>
    <tr>
      <td><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.list-1">List</a>&lt;<a class="xref" href="C1.CalcEngine.ExpressionEngine.IExpression.html">IExpression</a>&gt;</td>
      <td><span class="parametername">expr</span></td>
      <td><p>Arguments of the function.</p>
</td>
    </tr>
  </tbody>
</table>
<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.CalcEngine.ExpressionEngine.IExpression.html">IExpression</a></td>
      <td></td>
    </tr>
  </tbody>
</table>
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