else { if {} } and else if {}

Is there any difference between:

            else
            {
                if {}
            }

and

else if {}

For example,

            var statusValue = "Error";

            if (!canWrite)
            {
                statusValue = "NotOwner";
            }
            else
            {
                if (syncJob.Status == "Idle")
                {
                    statusValue = "InProgress";
                }
            }

and

            var statusValue = "Error";

            if (!canWrite)
            {
                statusValue = "NotOwner";
            }
            else if (syncJob.Status == "Idle")
            {
                    statusValue = "InProgress";
            }

Do the above both codes work in the same way?

The two versions of code you showed us do the same thing as each other, but they are not syntactically the same.

When you use the else if language element, you can cascade the clauses, something like this:

if (a == 1) {
  // some code
} else if (b == 2) {
  // some other code
} else if (c == 3) {
  // even more code
} else {
  // still more
}

Only one of the compound ( code surrounded by { } ) statements inside that example gets executed, guaranteed.

When you nest if within else, you don't get exactly the same thing. And if you write it that way when you want else if you'll make your code much harder to read. It's a good way to make your future self hate your present self when you must change or debug your code.

Consider

if (condition1)
    DoA();
else
    DoB();

Is exactly equivalent to

if (condition1)
{
    DoA();
}
else
{
    DoB();
}

I strongly recommend the latter because you are less likely to slip errors into your code doing maintenance when the brackets are there.

So...

if (condition1)
    DoA();
else if (condition2)
    DoB();
else
    DoC();

Is going to be the same as a version with brackets.

As long as you restrict yourself to single statements, you don't need brackets. The brackets demarcate blocks of statements, and both if and else can work equally well with either statements or blocks.

One thing that shakes out of all this is that

if (condition1)
    DoA();
else 
{
    if (condition2)
        DoB();
}
else
    DoC();

And

if (condition1)
    DoA();
else 
{
    if (condition2)
    {
        DoB();
    }
}
else
    DoC();

Are exactly equivalent to the previous bracket-free example

if (!canWrite)
{
    statusValue = "NotOwner";
}
// else is ran if the above is false and the condition is true
else if (syncJob.Status == "Idle")
{
    statusValue = "InProgress";
}


if (!canWrite)
{
    statusValue = "NotOwner";
}
// Runs if the above is false
else
{
    // Runs any code up to this point no matter the code condition below
    // Runs if the first is false and this is true
    if (syncJob.Status == "Idle")
    {
         statusValue = "InProgress";
    }
    // Runs any code up to this point no matter the code condition above
}

Syntax wise no, but when it is recompiled you will end up with different code... more jumps