C#.NET : konversi string to percent and dolars

untuk button1 adalah nameid dari tombol Format Text
ini untuk melakukan conversi ke dolar dan percent :

private void Button1_Click(object sender, System.EventArgs e)
{
this.TextBox2.Text = formatText(Convert.ToSingle(TextBox1.Text));
}

private void percentRadioButton_CheckedChanged(object sender, System.EventArgs e)
{
if (this.percentRadioButton.Checked)
{
formatText = new FormatNumbers.FormatSingle(FormatNumbers.returnPercentage);
}
}

private void dollarRadioButton_CheckedChanged(object sender, System.EventArgs e)
{
if (this.dollarRadioButton.Checked)
{
formatText = new FormatNumbers.FormatSingle(FormatNumbers.returnDollars);
}

}

private void Form1_Load(object sender, System.EventArgs e)
{
formatText = new FormatNumbers.FormatSingle(FormatNumbers.returnPercentage);
}