C＃if if是else if的优先级

Question

I have this specific piece of code in my project:

if (type == 1)
    if (line.StartsWith(user.PadRight(FieldLengths1[0])))
        keep = true;
    else if (type == 2)
        if (line.StartsWith(user.PadRight(FieldLengths2[0])))
            keep = true;

Originally, the indenting was different. The else-if is supposed to to be linked to "if (type == 1)", as the content would suggest. But Visual Studio seems to have changed my indentation to suggest that it is instead linked to the next if (if (line.startswith...))

This could be equivalent to

if (type == 1)
{
    if (line.StartsWith(user.PadRight(FieldLengths1[0])))
        keep = true;
}
else if (type == 2)
{
    if (line.StartsWith(user.PadRight(FieldLengths2[0])))
        keep = true;
}

Or to this:

if (type == 1)
{
    if (line.StartsWith(user.PadRight(FieldLengths1[0])))
        keep = true;
    else if (type == 2)
    {
        if (line.StartsWith(user.PadRight(FieldLengths2[0])))
            keep = true;
    }
}

I would like to know how does the else-if behave without brackets, and what exactly decides which if it would be linked to?

Answer 1

The else keyword is always linked to the closest if .

You should use braces to avoid this confusion.

Answer 2

The C# 5.0 Language Specification states in §8.7.1

An else part is associated with the lexically nearest preceding if that is allowed by the syntax.

Answer 3

Documentation on https://msdn.microsoft.com/en-us/library/aa664812(v=vs.71).aspx says:

pp-conditional:   pp-if-section   pp-elif-sectionsopt   pp-else-sectionopt   pp-endif

So, else keyword is matched greedy to the closest if.