Converting SQLMoney To C# Float ?

I'm using c# 2.0.

I have a datareader that reads an invoice line item from a table in my SQL Server database. The UnitPrice field is a Money field in SQL server. At the same time I have an invoice class in my application that has a UnitPrice property which is a float.

How do I convert the SQLMoney to a float using my datareader?

Right now I have:

cm.CommandText = "SELECT ItemID, Quantity, UnitPrice, Discount FROM tblInvoiceLineItems";

using (SqlDataReader dr = cm.ExecuteReader())

{

while (dr.Read())

{

LineItem li = new LineItem();

li.UnitPrice = (float)(double)dr.GetFloat(3);  // cast error here.

lineItems.Add(li);

}

}