如何从字符串中删除“http：//”部分？

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.)

Answer 2

The problem is how can i remove the http:// ?

You may use string.Replace , and replace the string with an empty string.

targetDirectory = targetDirectory.Replace("http://","");

or

targetDirectory = targetDirectory.Replace("http://",string.Empty);

both of them are same

Answer 3

Try this:

if(example.StartsWith("http://"))
{
    example.substring(7); 
}

Answer 4

You can always use the String.Replace to remove / replace characters in the string. Exampel:

targetDirectory = targetDirectory.Replace("http://", string.Empty);

And you can check if the string begins with Http:// by doing

if(targetDirectory.StartsWith("http://"))

Answer 5

You can use the replace characters in the string by string.Replace

if (targetDirectory.Contains("http://"))
{
    targetDirectory = targetDirectory.Replace("http://",string.Empty);
}