System.UnauthorizedAccessException was unhandled

Question

I am getting a access denied exception. How can I fix this?

Here is the exception:

System.UnauthorizedAccessException was unhandled HResult=-2147024891 Message=Access to the path 'c:\message.txt' is denied.
Source=mscorlib

Here is the code:

    public static void WriteToFile(string s)
    {
        fs = new FileStream("c:\\message.txt",
        FileMode.Append, FileAccess.Write);
        sw = new StreamWriter(fs);
        sw.WriteLine(s);
        sw.Flush();
        sw.Close();
        fs.Close();
    }

EDIT: It works if I run vs2012 as administrator, but is there a way or a reason to do it as normal user?

And this works:

    public static void WriteToFile(string s)
    {
        fs = new FileStream(@"C:\Users\KristjanBEstur\Documents\message.txt",
        FileMode.Append, FileAccess.Write);
        sw = new StreamWriter(fs);
        sw.WriteLine(s);
        sw.Flush();
        sw.Close();
        fs.Close();
        File.Delete(@"C:\Users\KristjanBEstur\Documents\message.txt");
    }

Solution 1

You may need to run your project in administrator mode if you want access to the root directory

You can do this by adding this to the app manifest

<requestedExecutionLevel level="requireAdministrator" uiAccess="true"/>

Solution 2

Double click on app.manifest file and if app.manifest not present Right click on your project, add -> New Item -> Application Manifest File then replace this line

<requestedExecutionLevel level="asInvoker" uiAccess="false" />

with this

<requestedExecutionLevel level="requireAdministrator" uiAccess="true" />

It will run your application with administrator privileges.

Solution 3

I'm not sure exactly what all might throw an UnauthorizedAccessException.

One idea though... you're trying to create a file directly in the c: drive, which is sometimes disallowed by system policy. For the sake of troubleshooting, try creating the file somewhere else that you'd have access to, like My Documents.

Comments

[somethingSomething]

There was a new exception when I used your code:System.IO.FileNotFoundException was unhandled HResult=-2147024894 Message=Could not find file 'c:\message.txt'. Source=mscorlib FileName=c:\message.txt

[Sudhakar Tillapudi]

@somethingSomething: now it is sure that there is no file message.txt in c: drive , did you check it?

[Sudhakar Tillapudi]

@somethingSomething: i have edited my answer for checking file exists or not, try it and please let me know the result.

[somethingSomething]

I want the file to be created if it doesn't exist. How would you do that?

[somethingSomething]

The code I have works if I run vs2012 as administrator. This is the problem.

[Sudhakar Tillapudi]

so it is clear that the file needs admin previliges to open the file, you can goto file properties,select security, from there hange the file permission for other users to open.access the file