Custom TextBox control: AppendLine Is there any way to improve this simple addition to the textbox control: appending a new line?

class CustomTextBox : TextBox
{
    public void AppendLine(string textData)
    {
        if (this.Text.EndsWith(Environment.NewLine) || this.Text == "")
        {
            this.AppendText(textData);
        }
        else
        {
            this.AppendText(Environment.NewLine + textData);
        }
    }  
}
I don't care for empty quotes designating an empty string. It should be replaced with String.Empty. It simply clarifies your intention and leaves no ambiguity that you perhaps forgot to put something in the quotes, or maybe even meant to put a space in there. Otherwise, I feel this is very simple and solid.