title: C# Adding Filter to combobox dropdown list
body: <p>Need some help with adding filter to my <code>ComboBox</code> drop down list(windows Forms Visual studio 2015)</p>
  
  <p>The drop down is populated as per below:</p>
  
  <pre><code>public ReconciliationReport()
  {
      InitializeComponent();
      AppDomain.CurrentDomain.AssemblyResolve += FindDLL;
  
      this.sRootDirectory = Properties.Resources.sRootDirectory;
  
      string[] arrProjectList = Directory.GetDirectories(sRootDirectory).Select(Directory =&gt; Path.GetFileName(Directory)).ToArray();
      Array.Sort(arrProjectList);
  
      int iProjectCount = arrProjectList.Length;
      this.DropDownListSize = iProjectCount;
  
      for (int i = 0; i &lt; iProjectCount; i++)
      {
          SelectJobDropdown.Items.Add(arrProjectList[i]);
      }
  }
  </code></pre>
  
  <p>This gives me a nice drop down list of all current directories. 
  <a href="https://i.stack.imgur.com/GjiTj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GjiTj.png" alt="enter image description here"></a></p>
  
  <p>Now, I need to add a filer to show only items which contain a text typed into the <code>ComboBox</code>itself regardless if the dropdown list itself is open or not. </p>
  
  <p>I have disabled both <code>AutoCompleteMode</code> and <code>AutoCompleteSource</code> as it was not working as expected with the opened droped down list. It was opening additonal list on top the existing one but I could only select from the dropdown under it. See print screen below:
  <a href="https://i.stack.imgur.com/1eaAQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1eaAQ.png" alt="enter image description here"></a></p>
  
  <p>The list on top is inactive and I cannot select the text but also does not give an option to display substrings. </p>
  
  <p>Only have one even for the box itself which is </p>
  
  <pre><code>private void SelectJobDropdown_SelectedIndexChanged(object sender, EventArgs e) 
  {
      //Plenty of code here 
  }
  </code></pre>
  
  <p>Can someone point in the right direction how to filter the list as I type within the box itself.</p>
  
  <p>Please  NOTE I have been using C# for only 3 weeks so might get confused with some of the terminology or other aspects of this language etc. </p>