新手问题，请大家帮忙！
做了一个添加页面，总是FormatException异常，代码如下：

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void btnSubmit_Click(object sender, EventArgs e)
{
//Pay是实体类
Pay pay = new Pay();
pay.name = this.lblname.Text;
pay.basepay = float.Parse(this.lblbasepay.Text);从这开始报异常！！！！！
pay.bonus = float.Parse(this.lblbonus.Text);
pay.factpay = float.Parse(this.lblfactpay.Text);
BusinessPay businesspay = new BusinessPay();
try
{
businesspay.PayInsert(pay);
Response.Write("alert('添加成功！')");
}
catch(Exception se)
{
Response.Redirect("Error.aspx?errInfo"+se.Message);
}
}
}

[解决办法]
int.Parse(null)则会产生异常
[解决办法]
lblbasepay.Text 的值不能装化为float 另外lblbasepay.Text不会为NULL

建议使用float.TryParse
float.fValue = 0;
if(!float.TryParse(lblbasepay.Text.Trim(),out fValue ))
//show error message and break