我这个是书上的例子，但这例子应该是印错了，在ButtonAdd的事件那，TextNewItem都没有申明是啥，我新手，想问问，TextNewItem应该怎么申明才能让这个读取文件内容到程序里的例子顺利运行
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;
using System.IO;
namespace steamwriter
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
void FillItems()
{
ComboItems.Items.Clear();
StreamReader sr = new StreamReader("Items.txt", Encoding.Default);
try
{
while (!sr.EndOfStream)
{
string NewItem = sr.ReadLine();
if (NewItem != "")
{
ComboItems.Items.Add(NewItem);
}
}
}
finally
{
sr.Close();
}
ComboItems.Text = ComboItems.Items[0].ToString();
}
private void Form1_Load(object sender, EventArgs e)
{
this.Text = "文本文件的读写";
FillItems();
}
private void ButtonAdd_Click(object sender, EventArgs e)
{
StreamWriter sw = new StreamWriter("item.txt ", true, Encoding.UTF8);
if (TextNewItem.text != "")
{
sw.WriteLine(TextNewItem.text);
}
else
{
MessageBox.Show("不能添加空选项", "操作失败", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
sw.Close();
FillItems();
MessageBox.Show("选项添加成功！", "操作完成", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}
