它是什麼

Created: November-22, 2018

允許在宣告變數時使用本地型別推斷。

什麼是型別推斷？

你可以在不明確宣告資料型別的情況下宣告區域性變數。編譯器根據其初始化表示式的型別推斷變數的資料型別。

選項推斷 ：

Dim aString  = "1234" '--> Will be treated as String by the compiler
Dim aNumber  = 4711   '--> Will be treated as Integer by the compiler

與顯式型別宣告：

'State a type explicitly
Dim aString as String = "1234"
Dim aNumber as Integer = 4711

選項推斷關閉：
Option Infer Off 的編譯器行為取決於此處已記錄的 Option Strict 設定。

Option Infer Off - Option Strict Off
所有沒有顯式型別宣告的變數都宣告為 Object。
```
Dim aString  = "1234" '--> Will be treated as Object by the compiler
```
選項推斷關閉 - 選項嚴格開啟
編譯器不允許你宣告沒有顯式型別的變數。
```
'Dim aString  = "1234" '--> Will not compile due to missing type in declaration
```