Public _result As Boolean = False
Public _form As CaptureCtrlForm = New CaptureCtrlForm()
Public Sub IndexContainsExample()
   Try
      ' reference the form capture control
      Dim capturectrl As CaptureCtrl = _form.CaptureCtrl

      ' set an audio device first, you should use your audio device name here
      If capturectrl.AudioDevices("USB") Is Nothing Then
         Throw New Exception("No USB audio device available")
      End If

      capturectrl.AudioDevices("USB").Selected = True

      ' reference the form capture control's audio inputs
      Dim inputs As AudioInputs = capturectrl.AudioInputs

      ' check for the master volume input
      Dim i As Integer = inputs.IndexOf("Master Volume")

      ' access the input via the collection indexer
      Dim ai As AudioInput = inputs(i)

      ' check if the collection contains this input 
      ' (it should we just got it with IndexOf above!)
      If inputs.Contains(ai) Then
         ' set the result to what we expect
         _result = True
      End If
   Catch e1 As Exception
      _result = False
   End Try
End Sub

public bool _result = false;
public CaptureCtrlForm _form = new CaptureCtrlForm();
public void IndexContainsExample()
{
   try
   {
      // reference the form capture control
      CaptureCtrl capturectrl = _form.CaptureCtrl;

      // set an audio device first, you should use your audio device name here
      if (capturectrl.AudioDevices["USB"] == null)
         throw new Exception("No USB audio device available");

      capturectrl.AudioDevices["USB"].Selected = true;

      // reference the form capture control's audio inputs
      AudioInputs inputs = capturectrl.AudioInputs;

      // check for the master volume input
      int i = inputs.IndexOf("Master Volume");

      // access the input via the collection indexer
      AudioInput ai = inputs[i];

      // check if the collection contains this input 
      // (it should we just got it with IndexOf above!)
      if (inputs.Contains(ai))
      {
         // set the result to what we expect
         _result = true;
      }
   }
   catch (Exception)
   {
      _result = false;
   }
}