Question

I have this method:

private List<string> offline(string targetDirectory)
{
    if (targetDirectory.Contains("http://"))
    {
        MessageBox.Show("true");
    }
    DirectoryInfo di = new DirectoryInfo(targetDirectory);
    List<string> directories = new List<string>();

    try
    {
        string[] dirs = Directory.GetDirectories(targetDirectory,"*.*",SearchOption.TopDirectoryOnly);
        for (int i = 0; i < dirs.Length; i++)
        {
            string t = "http://" + dirs[i];
            directories.Add(t);
        }
    }
    catch
    {
        MessageBox.Show("hgjghj");
    }


    return directories;

}

This is the part:

if (targetDirectory.Contains("http://"))
{
     MessageBox.Show("true");
}

I’m getting a directory which give me all the directories in this directory and I’m adding to each directory the string "http://".

The problem is when next time a directory is getting to the function its coming with "http://"

For example: http://c:\\ or http://c:\\windows

And then the line

 DirectoryInfo di = new DirectoryInfo(targetDirectory); // throws exception.

So I want that each time a directory is getting to the function to check if it starts with "http://" in the beginning, strip the "http://" part, get all the directories, and then add to each directory "http://" like now.

How can I remove "http://"?

Answer 1

I would be stricter than using Contains – I’d use StartsWith, and then Substring:

if (targetDirectory.StartsWith("http://"))
{
    targetDirectory = targetDirectory.Substring("http://".Length);
}

Or wrap it in a helper method:

public static string StripPrefix(string text, string prefix)
{
    return text.StartsWith(prefix) ? text.Substring(prefix.Length) : text;
}

It’s not clear to me why you’re putting the http:// as a prefix anyway though, to be honest. I can’t see how you’d expect a directory name prefixed with http:// to be a valid URL. Perhaps if you could explain why you’re doing it, we could suggest a better approach.

(Also, I really hope you don’t have a try/catch block like that in your real code, and that normally you follow .NET naming conventions.)