C# 程式設計/關鍵字/else

關鍵字 else 用於標識else 子句，它屬於一個 if 語句，其語法如下

if-statement ::= "if" "(" condition ")" if-body "else" else-body

condition ::= boolean-expression

if-body ::= statement-or-statement-block

else-body ::= statement-or-statement-block

一個 else 子句緊隨一個 if-body。當 condition 為 false 時，它提供要執行的程式碼。如果將 else-body 設定為另一個 if 語句，則會建立一個常見的 if、else if、else if、else if、else 語句的級聯

using System;

public class IfStatementSample
{
    public void IfMyNumberIs()
    {
        int myNumber = 5;
        if (myNumber == 4)
            Console.WriteLine("This will not be shown because myNumber is not 4.");
        else if(myNumber < 0)
        {
            Console.WriteLine("This will not be shown because myNumber is not negative.");
        }
        else if(myNumber%2 == 0)
            Console.WriteLine("This will not be shown because myNumber is not even.");
        else
        {
            Console.WriteLine("myNumber does not match the coded conditions, so this sentence will be shown!");
        }
    }
}

上面的例子只檢查 myNumber 是否小於 0，前提是 myNumber 不等於 4。它依次只檢查 myNumber%2 是否為 0，前提是 myNumber 不小於 0。由於所有條件都不成立，它會執行最終 else 子句的主體。

C# 關鍵字
abstract as base bool break byte case catch char checked class const continue decimal default delegate do double else enum event explicit extern false finally fixed float for foreach goto if implicit in int interface internal is lock long namespace new null object operator out override params private protected public readonly ref return sbyte sealed short sizeof stackalloc static string struct switch this throw true try typeof uint ulong unchecked unsafe ushort using var virtual void volatile while
C# 特殊識別符號（上下文關鍵字）
add alias async await dynamic get global nameof partial remove set value when where yield
上下文關鍵字（用於查詢）
ascending by descending equals from group in into join let on orderby select where