我尝试使用 FileStream 创建文件但出现异常，为什么？

Question

这是代码：

public OptionsFile(string settings)
    {
        
        if (File.Exists(settings))
        {
            
        }
        else
        {
        FileStream fs=File.Create(settings);

        fs.Close();
        }
        
        path_exe = Path.GetDirectoryName(Application.LocalUserAppDataPath);
        Options_File = settings;
        
    }

上线：FileStream fs=File.Create(settings);

由于某种原因，它无法创建该文件。在 Form1 中我在构造函数中做了：

Options_DB.Get_Video_File();

现在在 Options_DB 类中使用断点执行以下操作：

namespace test
{
    
    static class Options_DB
    {
        static string settings_dir;
        static string settings_file;
        static OptionsFile setting_file;
        static string path_settings;
        static string path_exe;
        static string outPutVideoFileDirectory;

        static Options_DB()
        {
            // ---  O P E N N I N G   S E T T I N G   F I L E   ;
            path_exe = Path.GetDirectoryName(Application.LocalUserAppDataPath);
            path_settings = Path.GetDirectoryName(Application.LocalUserAppDataPath);
            settings_file = "\\settings.txt";
            settings_dir = path_settings + @"\settings";
            setting_file = new OptionsFile(settings_dir + settings_file);

然后在OptionsFile中它正在做：

public OptionsFile(string settings)
    {
        
        if (File.Exists(settings))
        {
            
        }
        else
        {
        FileStream fs=File.Create(settings);

        fs.Close();
        }
        
        path_exe = Path.GetDirectoryName(Application.LocalUserAppDataPath);
        Options_File = settings;
        
    }

我在 OptionsFile 中使用了断点，并看到设置包含带有 settings.txt 文件的用户目录，但由于某种原因，它无法创建该行：

FileStream fs=File.Create(settings);

它停在 Form1 行上：Options_DB.Get_Video_File();

“ScreenVideoRecorder.Options_DB”的类型初始值设定项引发异常

System.TypeInitializationException was unhandled
  HResult=-2146233036
  Message=The type initializer for 'ScreenVideoRecorder.Options_DB' threw an exception.
  Source=ScreenVideoRecorder
  TypeName=ScreenVideoRecorder.Options_DB
  StackTrace:
       at ScreenVideoRecorder.Options_DB.Get_Video_File()
       at ScreenVideoRecorder.Form1..ctor() in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\Form1.cs:line 54
       at ScreenVideoRecorder.Program.Main() in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.IO.DirectoryNotFoundException
       HResult=-2147024893
       Message=Could not find a part of the path 'C:\Users\bout0_000\AppData\Local\ScreenVideoRecorder\ScreenVideoRecorder\settings\settings.txt'.
       Source=mscorlib
       StackTrace:
            at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
            at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
            at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize)
            at System.IO.File.Create(String path)
            at DannyGeneral.OptionsFile..ctor(String settings) in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\OptionsFile.cs:line 73
            at ScreenVideoRecorder.Options_DB..cctor() in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\Options_DB.cs:line 29
       InnerException: 

由于某种原因，在执行断点步骤后，无法创建 FileStream 。我猜这行有问题：FileStream fs=File.Create(settings);

尝试创建它时继续设置：

"C:\\Users\\user name\\AppData\\Local\\project dir\\project dir\\settings\\settings.txt"

但它永远不会创造它。

Answer 1

如果您阅读内部异常，您可以看到问题是该settings目录不存在。您可以通过调用 来解决此问题Directory.CreateDirectory，这会在指定路径中创建所有尚不存在的目录和子目录。（如果目录已经存在，则不会执行任何操作。）

我还建议用调用替换手动路径连接Path.Combine。

settings_dir = Path.Combine(path_settings, "settings");
Directory.CreateDirectory(settings_dir);  // create directory

settings_file = "settings.txt";
setting_file = new OptionsFile(Path.Combine(settings_dir, settings_file));