使用断点调试时，其余参数正常,，但strlist的值为null？这是哪里错了？

Question

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace WindowsFormsApplication1{public partial class Form1 : Form{public Form1(){InitializeComponent();}private void Form1_Load(object sender, EventArgs e){}private void button1_Click(object sender, EventArgs e){double corpusAmount, interestRate,interestAmount, incomeAmount;int depositYear; //本金，利率，利息，总收入，存期try // 录入数据{corpusAmount = double.Parse(this.corpusTextbox.Text);interestRate = double.Parse(this.interestRatetextBox.Text);depositYear = Int32.Parse(this.depositYeartextBox3.Text);}catch //异常处理{MessageBox.Show(" Input dismatached !");return;}incomeAmount = corpusAmount * (Math.Pow((1 + interestRate), depositYear)); //计算总收入interestAmount = incomeAmount - corpusAmount; //计算利息//格式化列表string strList;strList = string.Format(" {0,15:c } {1,15:c } ", interestAmount, incomeAmount);listBox1.Items.Add(strList); //输出```}}}

Answer 1

c后面 不要空格
double value1 = 16932.456;
double value2 = 15421.354;// {0,15:c } {1,15:c } 这个有空格 错误的
string result = String.Format("{0,15:c} {1,15:c}", value1, value2);

Answer 2

strList = string.Format(" {0,15:c } {1,15:c } "
这个是啥？{}里面不是占位符吧
format的用法是string.Format("{0},{1}",value1,value2);
{0}{1}都是占位符，分别对应value1和value2的值

Answer 3

返回的是2个double数值,一个得息,一个总收到,你用string.Format把他们转换成字符串,比如一个数是10.59,另一个数是11.49,stringList="10.59$11.49$"(15:C应该表示货币吧),你查下interestAmount,和incomeAmount有值么?