# C1.DataCollection.C1DataCollectionList-1.IndexOf

## Content

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



<h1 id="C1_DataCollection_C1DataCollectionList_1_IndexOf_" data-uid="C1.DataCollection.C1DataCollectionList`1.IndexOf*">IndexOf Method
</h1>
<div class="markdown level0 summary"></div>
<div class="markdown level0 conceptual"></div>



<a id="C1_DataCollection_C1DataCollectionList_1_IndexOf_" data-uid="C1.DataCollection.C1DataCollectionList`1.IndexOf*"></a>
<h4 id="C1_DataCollection_C1DataCollectionList_1_IndexOf_System_Object_" data-uid="C1.DataCollection.C1DataCollectionList`1.IndexOf(System.Object)">IndexOf(object?)</h4>
<div class="markdown level1 summary"><p>Determines the index of a specific item in the <a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.ilist">IList</a>.</p>
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<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">public int IndexOf(object? value)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Public Function IndexOf(value As Object) 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.object">object</a></td>
      <td><span class="parametername">value</span></td>
      <td><p>The object to locate in the <a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.ilist">IList</a>.</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="https://learn.microsoft.com/dotnet/api/system.int32">int</a></td>
      <td><p>The index of value if found in the list; otherwise, -1.</p>
</td>
    </tr>
  </tbody>
</table>
<h5 class="implements">Implements</h5>
    <div><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.ilist.indexof">IList.IndexOf(object)</a></div>


<a id="C1_DataCollection_C1DataCollectionList_1_IndexOf_" data-uid="C1.DataCollection.C1DataCollectionList`1.IndexOf*"></a>
<h4 id="C1_DataCollection_C1DataCollectionList_1_IndexOf__0_" data-uid="C1.DataCollection.C1DataCollectionList`1.IndexOf(`0)">IndexOf(T)</h4>
<div class="markdown level1 summary"><p>Determines the index of a specific item in the <a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ilist-1">IList&lt;T&gt;</a>.</p>
</div>
<div class="markdown level1 conceptual"></div>
<h5 class="declaration">Declaration</h5>
<div class="codewrapper">
  <pre><code class="lang-csharp hljs">public int IndexOf(T item)</code></pre>
</div>
<div class="codewrapper">
  <pre><code class="lang-vbnet hljs">Public Function IndexOf(item As T) 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><span class="xref">T</span></td>
      <td><span class="parametername">item</span></td>
      <td><p>The object to locate in the <a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ilist-1">IList&lt;T&gt;</a>.</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="https://learn.microsoft.com/dotnet/api/system.int32">int</a></td>
      <td><p>The index of value if found in the list; otherwise, -1.</p>
</td>
    </tr>
  </tbody>
</table>
<h5 class="implements">Implements</h5>
    <div><a class="xref" href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ilist-1.indexof">IList&lt;T&gt;.IndexOf(T)</a></div>
</div>