Illegal extension check c#-CodePudding

i have problem with my check for illegal extension i really dont know why is that not working here's my code

string[] BlacklistedExtensions = { "exe", "msi", "ps1", "reg", "vb", "vbe", "vbs", "scr", "bat", "cmd", "ws", "wsf", "wsh", "dll", "sys", "js" };

                    string[] Split = Filename.Split('.');
                    foreach (string Blacklisted in BlacklistedExtensions)
                    {
                        if (Split[Split.Length - 1] == Blacklisted)
                        {
                            WebData = "Illegal extension name";
                            Save = false;
                        }
                    }

CodePudding user response：

Why don't you consider using a HashSet for the BlacklistedExtensions. This will ensure you constant complexity when checking if the extension of the requested file is illegal. And my suggestion would look something like that:

// Initialize this HashSet with all the illegal extension values.
// As a second parameter, you can provide an IEqualityComparer<string> if you want to ignore the letter casing.
HashSet<string> blackListedExtensions = new HashSet<string>();
string extension = Filename.Split('.').LastOrDefault();
if (blackListedExtensions.Contains(extension))
{
    // This extension is illegal.
}

CodePudding user response：

try this

    string[] blacklistedExtensions = { "exe", "msi", "ps1", "reg", "vb", "vbe", "vbs", "scr", "bat", "cmd", "ws", "wsf", "wsh", "dll", "sys", "js" };

    string[] arr = Filename.Split('.');
    var ext = arr[arr.Length - 1];

    if (blacklistedExtensions.Any(e => e.Contains(ext)))
    {
        var WebData = "Illegal extension name";
        var Save = false;
    }