StreamReader

Question

StreamReader StringWriter定义了一个变量之后，编译器就不认识了？为什么，是不是要加载什么头文件？
 StringWriter wr = new StringWriter();
wr.WriteLine("Friendship is not a two way road.");
wr.WriteLine("It is a one way road travelled by two people.");
wr.Write(Writer.NewLine);
wr.close();
Console.WriteLine("Data: {0}",wr.ToString());
请各位看看

Answer 1

贴出全部代码
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace TestOne_09_7_7
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        private void open_Click(object sender, EventArgs e)
        {
       //     openFileDialog.ShowDialog();
            
             new System.IO.StreamReader SR;
            string S;
            SR = File.OpenText(filename);
            S = SR.ReadLine();
            while (S != null)
            {
                Console.WriteLine(S);
                S = SR.ReadLine();
            }
            SR.Close();
        }
    }
}

Answer 2

new System.IO.StreamReader SR; 
==>
System.IO.StreamReader SR; 

Answer 3

new System.IO.StreamReader SR; 对，去掉new

Answer 4

"是不是要加载什么头文件？"
楼主 C 转过来的?
代码有错,除了2楼说的,还少引用了 System.IO
修正如下:
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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
                 //    openFileDialog.ShowDialog(); 
            
            System.IO.StreamReader SR; 
            string S; 
            SR = File.OpenText(filename); 
            S = SR.ReadLine(); 
            while (S != null) 
            { 
                Console.WriteLine(S); 
                S = SR.ReadLine(); 
            } 
            SR.Close();         }
    }
}