Use GetInvalidFileNameChars to generate file names

Sometimes it is necessary to generate a file name using a string retrieved from the database if the string contains disallowed characters (\,? , < , > ), you also need to replace each of these characters one by one

The code is as follows:

public static string GetValidName(string fileName)
{
    foreach (char c in System.IO.Path.GetInvalidFileNameChars())
    {
        fileName = fileName.Replace(c, ' ');
    }
    return fileName;
}

In the same way, you can also determine if a string contains invalid characters.