Solomon

http://dotnettipoftheday.org/tips/SystemIOPathCombine.aspx

Let’s review the following code for creating a file path:

    public string GetFullPath(string fileName)
    {
        string folder = ConfigurationManager.AppSettings["MyFolder"];
        return folder + fileName;
    }

This code is prone to error. For example, when you set the folder setting, you have to remember to make sure it ends with a slash. To avoid such problems use Path.Combine() method which will ensure that the folder has ending slash:

    public string GetFullPath(string filename)
    {
        string folder = ConfigurationManager.AppSettings["MyFolder"];
        return Path.Combine(folder, filename);
    }

http://dotnettipoftheday.org/tips/double_question_mark_operator_cs.aspx

The ?? operator returns the left-hand operand if it is not null, or else it returns the right operand. For example:

int? x = null;

...

// y = x, unless x is null, in which case y = -1.

int y = x ?? -1;

The ?? operator also works with reference types:

//message = param, unless param is null
//in which case message = "No message"
string message = param ?? "No message";