Instance of the class and invoke the method does not perform the same

Question

Hey all I am trying to add a function method to VideoControl.cs so that I can call it from my Form1.cs button click. The code I am using is from a Github here.

Right now, in order to start a movie, I have to right-click inside the videoControl1 on the form and select Load from the ToolStripMenu.

Doing that it goes into the VideoControl.cs loadFileToolStripMenuItem_Click function:

private void loadFileToolStripMenuItem_Click(object sender, EventArgs e)
    {
        OpenFileDialog openFileDialog1 = new OpenFileDialog
        {
            Title = "Browse Video Files",
            CheckFileExists = true,
            CheckPathExists = true,
            DefaultExt = "ts",
            Filter = "All Media Files|*.MP4",
            FilterIndex = 2,
            RestoreDirectory = true,

            ReadOnlyChecked = true,
            ShowReadOnly = true
        };

        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            m_fileName = openFileDialog1.FileName;
            m_lastPlayedIsFile = true;
            Play(out string outMessage);
            
            if (pCallback != null)
            {
                foreach (IVideoControl p in pCallback)
                {
                    p.NotifyPlay(m_fileName, true);
                }
            }
        }
    }

So when I create a public function in VideoControl.cs like this so that I can just pass the video path to it without the need to select it form the browser select popup:

public static void testingVid(string theVideo)
    {
        m_fileName = theVideo;
        m_lastPlayedIsFile = true;
        Play(out string outMessage);

        if (pCallback != null)
        {
            foreach (IVideoControl p in pCallback)
            {
                p.NotifyPlay(m_fileName, true);
            }
        }
    }

And I am calling that like this from the Form1.cs:

VideoControl.testingVid(@"C:\Users\Admin\Videos\a_test_video.mp4");

I get the error on VideoControl.testingVid saying:

Error   CS0120  An object reference is required for the non-static field, method, or property 'VideoControl.testingVid(string)'

When I create an instance of the class and invoke the method like this:

VideoControl VC = new VideoControl();
VC.testingVid(@"C:\Users\Admin\Videos\a_test_video.mp4");

It works (no errors) but it does not perform the same as if I did the right-click menu option. No error but it never plays.

Stepping through the code for both methods they both have the same data at the end (the video path and p.NotifyPlay(m_fileName, true); value of 1 in the loop).

What am I missing here?