添加多个项目
同学们接下来会有这种需求：把完成作业和随堂练习区分开来，这时候没有必要建两个solution（一个VS，一次只能开一个solution）。

你可以在一个solution下面建两个项目。只需要在solution上点击右键：Add - New Project即可。

solution和project
VS用solution来归纳管理projects：一个solution下可以有多个project。

在文件夹中打开solution（即打开solution所在的文件夹），我们就会发现：solution对应这一个.sln文件。这个文件可以用记事本打开，里面记录的主要就是这个solution里面包含了哪些项目。

而一个project就对应着一个文件夹，该文件夹下又有一个.csproj文件。该文件一样可以用记事本打开，里面记录的主要就是这个project里面包含的各种文件，以及其他配置。

当我们在project中添加一个文件（夹）时，其实做了两件事：

在project所在文件夹中添加文件（夹）
在.csproj文件中添加记录，标明新添加的文件（夹）属于该project
要证明这一点，可以：

通过windows文件管理窗口在项目文件夹中添加一个新的文件，比如fg.txt，
然后在VS中查看，找不到fg.txt的
在VS的solution explorer中，点击：Show All Files

（演示：）

通常来说，solution下所有项目都放在当前文件夹下。

folder/solution folder

设置启动项

插入：solution 和 project，以便于代码管理，暂时理解成类似于“文件夹”和“文件”的关系

可删除：.vs/obj/bin

项目 ：.sln（solution） .csproj (CSharpProject)

添加project（tips: 善用Git比较）

solution folder：虚拟

remove project：删除与solution的关联，并不

选择启动项目
https://github.com/users/fghdfghdfg5/projects/952
https://github.com/users/fghdfghdfg5/projects/953
https://github.com/users/fghdfghdfg5/projects/954
https://github.com/users/fghdfghdfg5/projects/955
https://github.com/users/fghdfghdfg5/projects/956
https://github.com/users/fghdfghdfg5/projects/957
https://github.com/users/fghdfghdfg5/projects/958
https://github.com/users/fghdfghdfg5/projects/959
https://github.com/users/fghdfghdfg5/projects/960
https://github.com/users/fghdfghdfg5/projects/961
https://github.com/users/fghdfghdfg5/projects/962
https://github.com/users/fghdfghdfg5/projects/963
https://github.com/users/fghdfghdfg5/projects/964
https://github.com/users/fghdfghdfg5/projects/965
https://github.com/users/fghdfghdfg5/projects/966
https://github.com/users/fghdfghdfg5/projects/967
https://github.com/users/fghdfghdfg5/projects/968
https://github.com/users/fghdfghdfg5/projects/969
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https://github.com/users/fghdfghdfg5/projects/971
https://github.com/users/fghdfghdfg5/projects/972
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https://github.com/users/fghdfghdfg5/projects/974
https://github.com/users/fghdfghdfg5/projects/975
https://github.com/users/fghdfghdfg5/projects/976
https://github.com/users/fghdfghdfg5/projects/977
https://github.com/users/fghdfghdfg5/projects/978
https://github.com/users/fghdfghdfg5/projects/979
https://github.com/users/fghdfghdfg5/projects/980
https://github.com/users/fghdfghdfg5/projects/981
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https://github.com/users/fghdfghdfg5/projects/1009
https://github.com/users/fghdfghdfg5/projects/1010
https://github.com/users/fghdfghdfg5/projects/1011
https://github.com/users/fghdfghdfg5/projects/1012
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https://github.com/users/fghdfghdfg5/projects/1014
https://github.com/users/fghdfghdfg5/projects/1015
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