i am making mp3 player using c# but i am sufferring from this error "Cannot implicitly convert type 'string' to 'string[]"

i am making mp3 player using c# but i am sufferring from this error

"Cannot implicitly convert type 'string' to 'string[]".

namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }
    string[] f, p;

    private void button1_Click(object sender, EventArgs e)
    {
        OpenFileDialog open = new OpenFileDialog();
        if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {

            f = openFileDialog1.SafeFileName;
            p = openFileDialog1.FileName;
            for (int i = 0; i < f.Length; i++)
            {
                listBox1.Items.Add(f[i]);

            }
            foreach(string d in open.FileNames)
            { 
                listBox1.Items.Add(d);
            }
        }
    }

    private void listBox1_MouseDoubleClick(object sender, MouseEventArgs e)
    {
        axWindowsMediaPlayer1.URL = p[listBox1.SelectedIndex];

    }
}

}