C# Adding Filter to combobox dropdown list
<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>