I am trying to create a program that checks if the following file exists and if not, create one and write name to it. But the program doesn't create a file and doesn't throw any exceptions.
string verify;
string name = textBox1.Text;
string path = Path.Combine(#"C:\assets\"+ name + ".txt");
if (!File.Exists(path))
{
File.Create(path);
File.WriteAllText(path, name);
}
else if (File.Exists(path))
{
verify = File.ReadAllText(path);
if (verify == name)
{
return;
}
}
Make sure that the folder C:\assets exists, otherwise your program will throw an exception.
File.Create(path) will create the file, but when you call File.WriteAllText(path, name) it would throw an exception because your file may still be opened. Therefore you should remove File.Create(path), File.WriteAllText(path, name); will create a file and then close it after writing to it.
I would eliminate File.Create(path); from your code and see what happens. File.WriteAllText(path, name); will Create the file for you so it is unnecessary, and you may be getting an IO exception that is being swallowed up elsewhere in your code that is throwing you off the scent.
Related
When working with an application on C# I am creating a few temporary files using the following logic:
Creating Temp File
private static string CreateTmpFile()
{
string fileName = string.Empty;
try
{
// Get the full name of the newly created Temporary file.
// Note that the GetTempFileName() method actually creates
// a 0-byte file and returns the name of the created file.
fileName = Path.GetTempFileName();
// Craete a FileInfo object to set the file's attributes
FileInfo fileInfo = new FileInfo(fileName);
// Set the Attribute property of this file to Temporary.
// Although this is not completely necessary, the .NET Framework is able
// to optimize the use of Temporary files by keeping them cached in memory.
fileInfo.Attributes = FileAttributes.Temporary;
Console.WriteLine("TEMP file created at: " + fileName);
}
catch (Exception ex)
{
Console.WriteLine("Unable to create TEMP file or set its attributes: " + ex.Message);
}
return fileName;
}
Writing to Temp File
private static void UpdateTmpFile(string tmpFile)
{
try
{
// Write to the temp file.
StreamWriter streamWriter = File.AppendText(tmpFile);
streamWriter.WriteLine("Hello from www.daveoncsharp.com!");
streamWriter.Flush();
streamWriter.Close();
Console.WriteLine("TEMP file updated.");
}
catch (Exception ex)
{
Console.WriteLine("Error writing to TEMP file: " + ex.Message);
}
}
I have also tried and followed some of the implementations found on this link for another question
and am using the following implementations in my code : Storing the file in the AppData Folder for using the ACL
However I have been asked to make sure that :
The temp files cannot be read by anyone(Not even the user) during application runtime,
And to make sure that they are deleted even when force closing the
application
For case 1: The temp files cannot be read by anyone(Not even the user) during application runtime,
How can I implement this for my application files? The temp files contain sensitive data which should not be readable even if the user themselves would like to read. Is there a way I can do that?
For case 2: To make sure that they are deleted even when force closing the
application
Here I would like to make sure than even with force close or a sudden restart the files are deleted.
If Force close: then delete the files before force close
If Restart: then delete the files on next startup
Are these doable?
i try to write line in file when this exists:
My code is next:
string strRuta = "C:\File.txt"
if (!Directory.Exists(strRuta))
Directory.CreateDirectory(strRuta);
string psContenido = "Hola";
if (!(File.Exists(strRuta + strNombreArchivo)))
{
swArchivo = File.CreateText(strRuta + strNombreArchivo);
}
if (!psContenido.ToLower().Contains("error"))
{
swArchivo.WriteLine(psContenido);
swArchivo.Flush();
swArchivo.Close();
swArchivo.Dispose();
File.SetCreationTime(strRuta + strNombreArchivo, DateTime.Now);
}
but when run this program i have a error in WriteLine, i don´t undertand which is the reason, could you help me?
I would like to know how to write in the file(in the next line the word)
There are a couple of problems, I think. First, you're specifying what looks like a file name and creating a directory with that name (not sure if this is intentional or not). Second, you can use the static helper method AppendAllText of the File class to both create the file if it doesn't exist, and to write the contents to the end of the file. It handles all the streamwriter stuff for you, so you don't have to worry about calling close and dispose.
private static void Main(string[] args)
{
string directory = #"C:\private\temp";
string fileName = "MyFile.txt";
string filePath = Path.Combine(directory, fileName);
string fileContents = "This will be written to the end of the file\r\n";
// This will create the directory if it doesn't exist
Directory.CreateDirectory(directory);
// This will create the file if it doesn't exist, and then write the text at the end.
File.AppendAllText(filePath, fileContents);
File.SetCreationTime(filePath, DateTime.Now);
}
I need to move a file existing on a mapped folder named A:\ to another mapped folder B:\ using the code below
File.Move(#"A:\file.txt",#"B:\");
it return the error below
Could not find file 'A:\file.txt'.
i tried to open A:\file.txt in folder explorer and it open the file normally
It looks like File.Move only works for files on local drives.
File.Move actually invokes MoveFile which states that both source and destination should be:
The current name of the file or directory on the local computer.
You would be better by using a combination of File.Copy and File.Delete.
Copy the file from A to B, then delete the file from A.
As stated before, File.Move needs sourceFileName and destFileName.
And you are missing the Filename in the second parameter.
If you want to move you file and keep the same name you can Extract the File name from the sourceFileName with GetFileName and use it in your destFileName
string sourceFileName = #"V:\Nothing.txt";
string destPath = #"T:\";
var fileName = Path.GetFileName(sourceFileName);
File.Move(sourceFileName, destPath + fileName );
Here is a debug code:
public static void Main()
{
string path = #"c:\temp\MyTest.txt";
string path2 = #"c:\temp2\MyTest.txt";
try
{
if (!File.Exists(path))
{
// This statement ensures that the file is created,
// but the handle is not kept.
Console.WriteLine("The original file does not exists, let's Create it.");
using (FileStream fs = File.Create(path)) {}
}
// Ensure that the target does not exist.
if (File.Exists(path2)) {
Console.WriteLine("The target file already exists, let's Delete it.");
File.Delete(path2);
}
// Move the file.
File.Move(path, path2);
Console.WriteLine("{0} was moved to {1}.", path, path2);
// See if the original exists now.
if (File.Exists(path))
{
Console.WriteLine("The original file still exists, which is unexpected.");
}
else
{
Console.WriteLine("The original file no longer exists, which is expected.");
}
}
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
}
}
I have a method to get the folder path of a particular file:
string filePath = Path.Combine(Environment.GetFolderPath(
Environment.SpecialFolder.MyDocuments), "file.txt");
And later, I use this to read the text in the file:
StreamReader rdr = new StreamReader(filePath); // "C:\Users\<user>\Documents\file.txt"
string myString = rdr.ReadToEnd();
Trouble is, if the file doesn't exist, it throws a FileNotFoundException (obviously). I want to hopefully use an if/else to catch the error, in which the user can browse to find the file directly, but I'm not sure what to use to verify if filePath is valid or not.
For example, I can't use:
if (filePath == null)
because the top method to retrieve the string will always return a value, whether or not it is valid. How can I solve this?
While File.Exists() is appropriate as a start, please note that ignoring the exception can still lead to an error condition if the file becomes inaccessible (dropped network drive, file opened by another program, deleted, etc.) in the time between the call to File.Exists() and new StreamReader().
You can use File.Exists:-
if(File.Exists(filePath))
{
//Do something
}
else
{
}
string filePath = Path.Combine(Environment.GetFolderPath(
Environment.SpecialFolder.MyDocuments), "file.txt");
if(!File.Exists(filePath))
{
/* browse your file */
}
else
{
StreamReader rdr = new StreamReader(filePath); // "C:\Users\<user>\Documents\file.txt"
string myString = rdr.ReadToEnd();
}
Why would the code below throw a io.system.directorynotfound exception? I can't recreate the problem myself but another user of my code does see it, any ideas why?
Thanks
try
{
//create path
string strAppData = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData).ToString() + "\\MyApp\\Data\\logs";
//check path exists
if (!System.IO.File.Exists(strAppData))
{
System.IO.Directory.CreateDirectory(strAppData);
}
System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(strAppData);
int count = dir.GetFiles().Length;
if (count > 100)
{
string[] files = System.IO.Directory.GetFiles(strAppData);
foreach (string file in files)
{
System.IO.File.Delete(file);
}
}
this.fileName = fileName;
// delete the file if it exists
if (File.Exists(fileName))
{
//delete the file
File.Delete(fileName);
}
// write the data to the file
fs = File.OpenWrite(fileName);
sWriter = new StreamWriter(fs);
sWriter.WriteLine(headerText);
sWriter.Flush();
sWriter.Close();
}
catch (Exception exp)
{
throw new Exception(exp.Message);
}
Have you tried using System.IO.Directory.Exists rather than System.IO.File.Exists when checking to see if the path exists?
You're checking for the existence of a directory using System.IO.File rather than System.IO.Directory. It probably works on your machine because that directory already exists, and so the check doesn't matter.
Either way, you need to remember that the file system is volatile. Rather than checking existence, try to open the resource and handle the exception when it fails.
Check that the directory exists, not the file...
Although you're checking it, and creating it if it doesn't exist. You don't know if they have privelages to create the directory. So your Directory.CreateDirectory call may well be failing too and then sub-sequently the rest of the code will fail
http://msdn.microsoft.com/en-us/library/system.io.file.exists.aspx
"Remarks
The Exists method should not be used for path validation, this method merely checks if the file specified in path exists. Passing an invalid path to Existsl returns false. "
That is your error right there. Your validation does not ensure that the path to the file exists