How do I create directory if it doesn't exist

问题:

I have a piece of code here that breaks if the directory doesn't exist:

System.IO.File.WriteAllText(filePath, content);

In one line (or a few lines), is it possible to check if the directory leading to the new file doesn't exist and if not, to create it before creating the new file?

I'm using .NET 3.5.

回答1:

To Create

(new FileInfo(filePath)).Directory.Create() Before writing to the file.

....Or, If it exists, then create (else do nothing)

System.IO.FileInfo file = new System.IO.FileInfo(filePath);
file.Directory.Create(); // If the directory already exists, this method does nothing.
System.IO.File.WriteAllText(file.FullName, content);

回答2:

You can use following code

  DirectoryInfo di = Directory.CreateDirectory(path);

回答3:

As @hitec said, you have to be sure that you have the right permissions, if you do, you can use this line to ensure the existence of the directory:

Directory.CreateDirectory(Path.GetDirectoryName(filePath))

回答4:

You can use File.Exists to check if the file exists and create it using File.Create if required. Make sure you check if you have access to create files at that location.

Once you are certain that the file exists, you can write to it safely. Though as a precaution, you should put your code into a try...catch block and catch for the exceptions that function is likely to raise if things don't go exactly as planned.

Additional information for basic file I/O concepts.

回答5:

var filePath = context.Server.MapPath(Convert.ToString(ConfigurationManager.AppSettings["ErrorLogFile"]));

var file = new FileInfo(filePath);

file.Directory.Create(); If the directory already exists, this method does nothing.

var sw = new StreamWriter(filePath, true);

sw.WriteLine(Enter your message here);

sw.Close();