Two or more cameras switch problem

[zhchlmm]

When I use more than one cameras and switch from one to another, the first one sometimes closed but sometimes did not close properly.

Before I open a new camera, I stop the camera by following code:

if (this.captureDevice != null)
{
// Discard capture device.
if (this.captureDevice.IsRunning)
{
await this.captureDevice.StopAsync();
}

if (this.captureDevice != null)
{
    await this.captureDevice.DisposeAsync();
    //this.captureDevice.Dispose();
    this.captureDevice = null;
}

}

Is there anything wrong?