File list (Check if you may need any files):
ch4系统
.......\ch4_1
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_1.csproj
.......\.....\ch4_1.csproj.user
.......\.....\ch4_1.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_2
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_2.csproj
.......\.....\ch4_2.csproj.user
.......\.....\ch4_2.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_3
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_3.csproj
.......\.....\ch4_3.csproj.user
.......\.....\ch4_3.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_4
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_4.csproj
.......\.....\ch4_4.csproj.user
.......\.....\ch4_4.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_5
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_5.csproj
.......\.....\ch4_5.csproj.user
.......\.....\ch4_5.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_6
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_6.csproj
.......\.....\ch4_6.csproj.user
.......\.....\ch4_6.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug
.......\ch4_7
.......\.....\AssemblyInfo.cs
.......\.....\bin
.......\.....\...\Debug
.......\.....\ch4_7.csproj
.......\.....\ch4_7.csproj.user
.......\.....\ch4_7.sln
.......\.....\Form1.cs
.......\.....\Form1.resx
.......\.....\obj
.......\.....\...\Debug