Question

I’m developing a C# web application in VS 2008. I let the user select an input file and then I store the file path in a string variable. However, it stores this path as "C:\\folder\\...". So my question is how do I convert this file path into single “\”?

Thank you guys for all your helps! Please forgive me as I am a newbie to ASP.NET development. This is more of my code in context. First I want to see if the directory exists. I guess I don’t have to check this if I check if the file exists. But this should still work right? And currently my “path” string variable is not showing up the way I need it to. I’m not sure how to formulate this statement. Eventually I want to execute the ReadAllText statement (see the last line).

protected void btnAppend_Click(object sender, EventArgs e)
{
    string fullpath = Page.Request.PhysicalPath;
    string fullPath2 = fullpath.Replace(@"\\", @"\");

    if (!Directory.Exists(fullpath2))
    {
    string msg = "<h1>The upload path doesn't exist: {0}</h1>";
    Response.Write(String.Format(msg, fullpath2));
    Response.End();
}
    string path = "@" + fullpath2 + uploadFile.PostedFile.FileName; 

    if (File.Exists(path))
    {
        // Create a file to write to.
        try
        {
            StreamReader sr = new StreamReader(path);
            string s = "";
            while(sr.Peek() > 0)
                s = sr.ReadLine();
            sr.Close();
        }
        catch (IOException exc)
        {
            Console.WriteLine(exc.Message + "Cannot open file.");
            return; 
        }
    }

    if (uploadFile.PostedFile.ContentLength > 0)
    {

        inputfile = System.IO.File.ReadAllText(path);

Answer 1

For a start, calling fullpath.Replace() does nothing to fullpath; it returns a new string. Also, when your string literals have a \ (backslash) in them, you need to tell the compiler that you’re not trying to use an escape sequence:

fullpath = fullpath.Replace(@"\\", @"\"); 

The @ means “please treat this string literally (verbatim)”. In other words, “when I say backslash, I mean backslash!”

See http://msdn.microsoft.com/en-us/library/362314fe.aspx.

Edit:

As LeBleu mentioned, you are calling Directory.Exists() on a full filepath. This won’t work; you need to extract the directory part from the path. Try this:

if (!Directory.Exists(Path.GetDirectoryName(fullpath)))
{
     ...
}