C#—文件操作—实验12.3

﹏ヽ暗。殇╰゛Y 2022-09-21 16:18 87阅读 0赞

/*
     * 要求：
     * 第一次单击“保存”时，弹出一个对话框，并将内容保存到指定的文件夹中；以后再单击“保存”按钮，自动将最新内容保存下来，不再弹出对话框。
     */
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Linq;
    using System.Text;
    using System.IO;
    using System.Windows.Forms;
    
    namespace WindowsFormsApplication1
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void Form1_Load(object sender, EventArgs e)
            {
    
            }
            private string fileName;
            private bool f = true;
            private void button1_Click(object sender, EventArgs e)
            {
                if (f)
                {
                    if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                    {
                        fileName = saveFileDialog1.FileName;
                        StreamWriter sw = new StreamWriter(fileName);        //制定写入流
                        sw.Flush();            //清理缓冲区
                        //写入内容
                        sw.BaseStream.Seek(0, SeekOrigin.Begin);
                        sw.Write(richTextBox1.Text);          //将richTextBox内容写入文件
                        f = false;
                        sw.Close();    //此句必须有，否则保存为空，不知道为什么
                    }
                }
                else
                {
                    StreamWriter sw = new StreamWriter(fileName);
                    sw.Flush(); 
                    sw.BaseStream.Seek(0, SeekOrigin.Begin);
                    sw.Write(richTextBox1.Text);          //将richTextBox内容写入文件
                    sw.Close();
                }
            }
    
            private void button2_Click(object sender, EventArgs e)
            {
                Application.Exit();
            }    
        }
    }

运行结果：

![Center][]

[Center]: /images/20220721/cd62b9d3cad04c0581f068bdbd6fb51a.png