C# Default optional parameter chooser

    public ClassType(string type) {
        Type = type;
    }
    public ClassType(string type,bool isArray=false) {
        Type = type;
        IsArray = isArray;
    }


    ClassType ct = new ClassType("adsf"开发者_如何学JAVA);

Which constructor is chosen?

The overload that doesn't require an optional parameter. Note that it's just a "yes" or "no" decision here: "no optional parameters filled in automatically" is preferable to "some optional parameters filled in automatically" but there's no preference between 1 or 2 being filled in. (That would be ambiguous.)

From section 7.5.3.2 of the C# 4 spec:

Otherwise if all parameters of M_P have a corresponding argument whereas default arguments need to be substituted for at least one optional parameter in M_Q then M_P is better than M_Q.

As Jon said, in two words, the first one. The match is 'cleaner'.