I got it -

private void button3_Click(object sender, EventArgs e)
{
byte[] inkBytes = Convert.FromBase64String(textBox1.Text);
inkPicture1.InkEnabled = false;
inkPicture1.Ink = new Microsoft.Ink.Ink();
inkPicture1.Ink.Load(inkBytes);
inkPicture1.InkEnabled = true;
inkPicture1.Invalidate();
}

Don;t worry!