Converting from vb.net to c#, switch function not working

Question

So I have been working on a small project (Previously built with vb.net) in C# ( Being honest, I have used an online vb.net to c# converter to get to this point.) that will basically rename the suffix of a set of files to specific predetermined names (hard coded).

Firstly the working part...

Press button_1, a file dialogue opens and you select files. These are then populated into a listbox_1.

Now press button_2 and the files from listbox_1 are renamed and sent to listbox_2.

Now the issue I am having...

For some reason I cannot figure out, the names are not being changed through the switch statement, they are just taking the string variable name and populating listbox_2 with blank entries (Because the starting Variable is empty).

string NewFileName = "";

I'm not sure what is happening here at all so if anyone is able to help me out that would be great.

 private string GetNewName(string OriginalFileName)
    {
        string NewFileName = "";

        switch (true)
        {
            case object _ when OriginalFileName.Contains(".0001"):
                {
                    NewFileName = OriginalFileName.Replace(".0001", "APPLE");
                    break;
                }

            case object _ when OriginalFileName.Contains(".0002"):
                {
                    NewFileName = OriginalFileName.Replace(".0002", "PEAR");
                    break;
                }
        }

        return NewFileName;
    }

private void BTN_ProcessNames_Click(object sender, EventArgs e)
    {
        foreach (Tuple<string, string> t in listbox_1.Items)
        {
           var NewName = GetNewName(t.Item2);
           listbox_2.Items.Add(NewName);
        }
    }

Answer 1

I would create a mapping:

private static readonly IReadOnlyDictionary<string, string> _mapping = new Dictionary<string, string>()
{
    { "0001", "APPLE" },
    { "0002", "PEAR" }
};

And then a method to extract the id, look it up in the mapping, and replace it:

private string GetNewName(string originalFileName)
{
    // if the path is c:\test\Green_.0001.jpg then we'll end up with filePath containing c:\test and fileName containing Green_.0001.jpg
    string filePath = Path.GetDirectoryName(originalFileName);
    string fileName = Path.GetFileName(originalFileName); // get only the name part

    // Split the filename by .
    string[] parts = fileName.Split('.');

    // If we have enough parts in the filename try and extract the id and replace it
    if (parts.Length >= 2)
    {
        // extract the id (e.g. 0001)
        string id = parts[parts.Length - 2];

        // look it up in the mapping dictionary
        if (_mapping.TryGetValue(id, out var newName))
        {
            // join everything up to the id (i.e. Green_)
            string leftPart = string.Join(".", parts.Take(parts.Length - 2));
            // Append the new name and the last part (the extension)
            fileName = $"{leftPart}{newName}.{parts.Last()}";
        }
    }

    // Recombine the filePath and fileName
    return Path.Combine(filePath, fileName);
}

Note that this method will return the original filename if the id isn't in the mapping, or the filename doesn't contain enough .s.

Try it online

Answer 2

Use if else statement. If you want to use switch then check at first and then use the switch.

Use below link for reference.

Use string.Contains() with switch()