实现效果:

知识运用:
Reistry类的SetValue
实现代码:
private void button1_Click(object sender, EventArgs e)
{
Registry.SetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Directory\shell\Open_Command","","在命令行打开");
Registry.SetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Directory\shell\Open_Command\Command", "", "cmd.exe %1");
}