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版本：VS2015

語言：C# WPF

功能：

在Window1的TextBox1中輸入資料。點選Button1，生成txt檔案儲存TextBox1中的數值，並啟動Window2。點選Button2，讀取txt檔案中的字串自動輸入TextBox2.

缺點：

TextBox1中有多個數據時，無法讓TextBox2輸入指定某一行的資料。

TextBox1中的資料不能刪除之前的資料。

改進思考：

1.每次Button2啟動後刪除*.txt檔案

2.規定*.txt檔案中分多個string str = ？？？區分賦值

參考文章：

【WPF用FileStream】【Winform用StreamReader或StreamWriter】

Window1：

<Window x:Class="Test.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Test"
        mc:Ignorable="d"
        Title="Window1" Height="350" Width="525">
    <Grid>
        <TextBox x:Name="textBox1" HorizontalAlignment="Left" Height="23" Margin="146,108,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
        <Button x:Name="button1" Content="Button1" HorizontalAlignment="Left" Margin="198,186,0,0" VerticalAlignment="Top" Width="75" Click="button1_Click"/>

    </Grid>
</Window>
 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;//新增引用

namespace Test
{
    /// <summary>
    /// MainWindow.xaml 的互動邏輯
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            WriteFile("E:\\123.txt", textBox1.Text);
            Window2 w2 = new Window2();
            w2.ShowDialog();
        }
        /// <summary>
        /// 寫檔案
        /// </summary>
        /// <param name="Path">檔案路徑</param>
        /// <param name="Strings">檔案內容</param>
        public static void WriteFile(string Path, string Strings)
        {
            if (!System.IO.File.Exists(Path))
            {
                //Directory.CreateDirectory(Path);
                System.IO.FileStream f = System.IO.File.Create(Path);
                f.Close();
                f.Dispose();
            }
            System.IO.StreamWriter f2 = new System.IO.StreamWriter(Path, true, System.Text.Encoding.UTF8);
            f2.WriteLine(Strings);
            f2.Close();
            f2.Dispose();
        }
    }
}

Window2：

<Window x:Class="Test.Window2"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Test"
        mc:Ignorable="d"
        Title="Window2" Height="300" Width="300">
    <Grid>
        <Button x:Name="button2" Content="Button2" HorizontalAlignment="Left" Margin="121,173,0,0" VerticalAlignment="Top" Width="75" Click="button2_Click"/>
        <TextBox x:Name="textBox2" HorizontalAlignment="Left" Height="23" Margin="121,101,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>

    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace Test
{
    /// <summary>
    /// Window2.xaml 的互動邏輯
    /// </summary>
    public partial class Window2 : Window
    {
        public Window2()
        {
            InitializeComponent();
        }

        private void button2_Click(object sender, RoutedEventArgs e)
        {
            textBox2.Text = ReadFile("E:\\123.txt");
        }

        private string ReadFile(string Path)
        {
            //宣告一個FileStream類的物件  
            FileStream fsRead = new FileStream(Path, FileMode.OpenOrCreate, FileAccess.Read);
            byte[] buffer = new byte[200];//宣告一個位元組陣列，用來臨時儲存讀取到資料，最大儲存200位元組  
            string a = null;
            while (true)
            {
                int r = fsRead.Read(buffer, 0, buffer.Length);//返回本次實際讀取到的位元組數   
                if (r == 0)//如果讀取到的位元組數為0，說明已到達檔案結尾，則退出while迴圈  
                {
                    break;
                }
                string s = Encoding.UTF8.GetString(buffer, 0, r);//將位元組陣列轉換成字串；buffer：要轉換的位元組陣列；0：第一個要解碼的位元組的索引；r：要解碼的位元組數   
                Console.WriteLine(s);
                a = s;
            }
            return a;
            fsRead.Close();  //關閉流  
            fsRead.Dispose(); //釋放流  
            Console.ReadKey();
        }
    }
}