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標(biāo)簽: 基本數(shù)據(jù)類型的拓展類

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分享值得反思的VBA數(shù)據(jù)類型的拓展類: 熱度 1 ganlinlao 2017-3-11 12:41; 值得反思的 VBA 數(shù)據(jù)類型的拓展類 VBA 用了很多年了，它的內(nèi)建數(shù)據(jù)類型應(yīng)該很多人都非常熟悉。 Boolean 數(shù)據(jù)類型　　變量存儲(chǔ)為 16 位只能是 True 或是 False Byte 數(shù)據(jù)類型　　　　變量存儲(chǔ)為 8 位范圍在 0 至 255 之間 Currency 數(shù)據(jù)類型　　變量存儲(chǔ)為 64 位范圍可以從 -922,337,203,685,477.5808 到 922,337,203,685,477.5807 Date 數(shù)據(jù)類型　　　　變量存儲(chǔ)為 64 位日期范圍從 100 年 1 月 1 日到 9999 年 12 月 31 日，時(shí)間可以從 0:00:00 到 23:59:59 。 Decimal 數(shù)據(jù)類型　　變量存儲(chǔ)為 96 位 Double 數(shù)據(jù)類型　　變量存儲(chǔ)為 64 位 Integer 數(shù)據(jù)類型　　變量存儲(chǔ)為 16 位　　范圍為 -32,768 到 32,767 之間 Long 數(shù)據(jù)類型　　　變量存儲(chǔ)為 32 位　　范圍從 -2,147,483,648 到 2,147,483,647 Object 數(shù)據(jù)類型　　存儲(chǔ)為 32 位（ 4 個(gè)字節(jié)）的地址形式 Single 數(shù)據(jù)類型變量存儲(chǔ)為 IEEE 32 位 String 數(shù)據(jù)類型字符串有兩種：變長(zhǎng)與定長(zhǎng)的字符串。變長(zhǎng)字符串最多可包含大約 20 億 ( 2^31) 個(gè)字符。定長(zhǎng)字符串可包含 1 到大約 64K ( 2^16 ) 個(gè)字符。用戶定義數(shù)據(jù)類型 UDT Variant 數(shù)據(jù)類型 Variant 是一種特殊的數(shù)據(jù)類型，除了定長(zhǎng) String 數(shù)據(jù)及用戶定義類型外，可以包含任何種類的數(shù)據(jù)。 Variant 也可以包含 Empty 、 Error 、 Nothing 及 Null 等特殊值。可以用 VarType 函數(shù)或 TypeName 函數(shù)來(lái)決定如何處理 Variant 中的數(shù)據(jù) 一般的基礎(chǔ)數(shù)據(jù)類型，在一個(gè) sub 或 function 中，它的變量作用域只能固定在本函數(shù)中，也就是調(diào)用這個(gè)函數(shù)時(shí)，變量在棧上自動(dòng)生成，調(diào)用完，它的變量自動(dòng)在棧上清除。 Public 和 static 靜態(tài)變量除外。這樣子的機(jī)制，無(wú)形中能夠節(jié)省很多內(nèi)存。但在今天，“一切都是對(duì)象”的口號(hào)下，很多語(yǔ)言的內(nèi)建數(shù)據(jù)類型本身也是對(duì)象。換句話說(shuō)，數(shù)據(jù)類型本身也是類。這會(huì)帶來(lái)了便利性，但同時(shí)也意味性能的損耗。因?yàn)榍宄粋€(gè)對(duì)象遠(yuǎn)遠(yuǎn)比在棧上清除一個(gè)變量要復(fù)雜一些。一般語(yǔ)言的類的構(gòu)造器和析構(gòu)器，都是屬于類的本身內(nèi)部。但 vba 很特殊，它的構(gòu)造器是在外部，即 iClassFactory ，析構(gòu)器是在內(nèi)部，但你必須祈禱當(dāng) set object=nothing 時(shí)，引用計(jì)數(shù)能變成 0 ，這樣才有辦法去清除對(duì)象�？傊@個(gè)析構(gòu)過(guò)程也不是那么清晰明朗。因?yàn)檫@個(gè)特殊性，所以我們才有必要對(duì) VBA 數(shù)據(jù)類型拓展到底有沒有必要，進(jìn)行斟酌。但毫無(wú)疑問(wèn)數(shù)據(jù)類型拓展，會(huì)帶來(lái)很多便利性。其中 VBA 數(shù)據(jù)類型，最需要被拓展的就是數(shù)組和字符串，其它的數(shù)值，相比較而言，意義不那么大。數(shù)組Array的拓展類： Public Property Get BoundL(Optional ByVal Dimension As Long) As Long '相當(dāng)于Lbound()函數(shù)，返回某維數(shù)組的下標(biāo)， Dimension:表示維數(shù)，維數(shù)必須0且=總維數(shù)。如果未指定維數(shù)，默認(rèn)使用第一維 Public Property Get BoundU(Optional ByVal Dimension As Long) As Long Public Property Get Data() As Long '返回?cái)?shù)組第一個(gè)元素?cái)?shù)據(jù)的指針。注意：元素?cái)?shù)據(jù)在內(nèi)存中的指針并不等于數(shù)組的指針 Public Property Get Dimensions() As Long '返回?cái)?shù)組的總維數(shù)，如二維數(shù)組返回2，三維數(shù)組返回3 Public Property Get Elements(Optional ByVal Dimension As Long) As Long '返回某維數(shù)組的元素總數(shù)。相當(dāng)于Ubound()-Lbound() Public Property Get ElementSize() As Long '返回?cái)?shù)組所有元素總的字節(jié)大小 Public Property Get Item(ParamArray Indexes()) As Variant Public Property Let Item(ParamArray Indexes(), ByRef NewValue As Variant) Public Property Get Pointer() As Long '返回當(dāng)前數(shù)組的指針。該指針指向數(shù)組的首地址。注：可以用指針值來(lái)判斷數(shù)組是否存在（非0）或不存在（等于0） Public Property Get Type_() As VbVarType '返回?cái)?shù)組元素的數(shù)據(jù)類型 Public Property Get Value() As Variant '返回?cái)?shù)組元素的值，默認(rèn) Public Property Let Value(ByRef NewValue As Variant) Public Function Add(ByRef Item As Variant) As ArrayEx '在當(dāng)前數(shù)組最后一維追加一個(gè)元素，如果數(shù)組類的數(shù)組不存在，將按該元素的數(shù)據(jù)類型初始化數(shù)組，并確保數(shù)組元素是該元素的數(shù)據(jù)類型 Public Function AddRange(ByRef Range As Variant) As ArrayEx '在當(dāng)前數(shù)組的最后一維追加一系列元素。 Range: 一般是一維數(shù)組，注意：該系列的元素?cái)?shù)據(jù)類型必須和數(shù)組類中已存在的數(shù)組元素是相同的數(shù)據(jù)類型，否則數(shù)組類的數(shù)組無(wú)法追加。例子： Dim a As New ArrayEx Dim b(2) As Long b(0) = 123: b(1) = 456: b(2) = 789 MsgBox a.AddRange(b).Item(2) '顯示 789 Set a = Nothing Public Function Clone() As ArrayEx 例子： Dim a As New ArrayEx Dim a2 As New ArrayEx a.Create(vbByte, 1, Array(0, 1)).Item(0) = 255 Set a2 = a.Clone a2.Item(0) = 100 MsgBox a.Item(0) vbCrLf a2.Item(0) '顯示 255 and 100 Set a = Nothing Set a2 = Nothing Public Function Create(ByVal ArrayType As VbVarType, ParamArray Bounds()) As ArrayEx '創(chuàng)建一個(gè)新數(shù)組。 ArrayType：數(shù)組的數(shù)據(jù)類型 Bounds()：數(shù)組每一維的元素個(gè)數(shù)，Bounds最大值是32 Dim a As New ArrayEx a.Create vbLong, 2, Array(0, 4), Array(-1, 10) '定義二維數(shù)組5行，12列 Set a = Nothing Public Function Destroy() As ArrayEx '銷毀數(shù)組類數(shù)組并自動(dòng) set 數(shù)據(jù)類對(duì)象=nothing Public Function Parse(ByRef Value As Variant) As ArrayEx '轉(zhuǎn)換數(shù)據(jù)類型并賦值給數(shù)組元素 Public Function Resize(ByVal NewUpperBound As Long) As ArrayEx '重置數(shù)組類數(shù)組最后一維的大小，如果 NewUpperBoundOld UpperBound，將追加元素總數(shù)大小，如果小于，將裁剪元素總數(shù)大小。 String 類型拓展： Public Property Get Asc(Optional ByVal Index As Long) As Long '返回字符串指定位置的字符的ASNI碼，index是字符在字符串中的位置，必須0且Length大小，否則函數(shù)返回0 Public Property Get Capacity() As Long '返回內(nèi)存分配的字符串緩存區(qū)字節(jié)大小 Public Property Get Length() As Long '返回字符串的大小 Public Property Get Pointer() As Long '返回字符串緩存區(qū)的指針 Public Property Get Value() As String '返回字符串，默認(rèn)值 Public Property Let Value(ByRef NewValue As String) '對(duì)字符串賦值 Public Function Clone() As StringEx '新建一個(gè)相同的String類，深復(fù)制當(dāng)前String對(duì)象，包括數(shù)據(jù)結(jié)構(gòu)和數(shù)據(jù) 例子： Dim s As New StringEx MsgBox s.Parse("Hello World").Clone.Parse("!!!") '顯示 !!! MsgBox s '顯示 Hello World Set s = Nothing Public Function Compare(ByRef CompareString As String, Optional ByVal CompareMethod As VbCompareMethod) As IntegerEx '比較字符串 CompareString:被比較字符串，如果 CompareString大于當(dāng)前類的字符串，返回-1；如果相等，返回0；如果小于，返回1；例子： Dim s As New StringEx MsgBox s.Parse("Hello World").Compare("hello world") '顯示 -1 Set s = Nothing Public Function Concat(ByRef ConcatString As String) As StringEx ' 字符串拼接，Concat是基于內(nèi)存緩存直接拼接，效率要高于傳統(tǒng)的或+的字符串拼接。例子：Dim s As New StringEx MsgBox s.Parse("Hello World").Concat("!!!") '顯示 Hello World!!! Set s = Nothing Public Function ConcatPointer(ByVal ConcatStringPointer As Long) As StringEx '以指針的方式進(jìn)行字符串拼接， ConcatPointer 比Concat方法快10倍左右例子： Dim i As Long Dim p As String Dim s As New StringEx Dim t As String t = "Hello World! " p = StrPtr(t) For i = 1 To 300000 s.ConcatPointer p Next i MsgBox s '顯示 300 000 次 Hello World!拼接非�？� Set s = Nothing Public Function Duplicate(ByVal Count As Long) As StringEx ' 以指定次數(shù)，重復(fù) 同一字符例子： Dim s As New StringEx MsgBox s.Parse("Hello World ").Duplicate(2) '顯示 Hello World Hello World Hello World Set s = Nothing Public Function Find(ByRef SearchString As String, Optional ByVal Start As Long, Optional ByVal Reverse As Boolean, Optional ByVal CompareMethod As VbCompareMethod) As LongEx '查找子字符串在字符串中的位置。Reverse:是指從左向右，還是從右向左例子： Dim s As New StringEx MsgBox s.Parse("Hello World ").Find("World") '顯示 7 Set s = Nothing Public Function Insert(ByVal Index As Long, ByRef InsertString As String) As StringEx Public Function Left(ByVal Length As Long) As StringEx Public Function Lower() As StringEx Public Function Mid(ByVal Start As Long, Optional ByVal Length As Long) As StringEx Public Function Numeric() As StringEx '清除字符串中非數(shù)值，并只返回?cái)?shù)值部分例子： Dim s As New StringEx MsgBox s.Parse("Hello 123 World").Numeric '顯示 123 Set s = Nothing Public Function PadRight(ByVal Width As Long) As StringEx Public Function Parse(ByRef Value As Variant) As StringEx '對(duì)任何可以轉(zhuǎn)換成String的值進(jìn)行轉(zhuǎn)換并賦值給String類的字符串。注：一維的Byte數(shù)組被視作字符串?dāng)?shù)組，Parse方法將先檢查數(shù)組的Bom(UTF-8, UTF-16 BE/LE)和字節(jié)大小，然后開始轉(zhuǎn)換。對(duì)于常見的任何字符集編碼如utf-8等，都可以通Parse方法轉(zhuǎn)化成vb能用的string類型例子： Dim bAnsi(4) As Byte Dim bUnicodeBOM(11) As Byte Dim bUnicode(9) As Byte Dim s As New StringEx bAnsi(0) = 72: bAnsi(1) = 101: bAnsi(2) = 108: bAnsi(3) = 108: bAnsi(4) = 111 bUnicodeBOM(0) = 255: bUnicodeBOM(1) = 254: bUnicodeBOM(2) = 72: bUnicodeBOM(3) = 0: bUnicodeBOM(4) = 101: bUnicodeBOM(5) = 0: bUnicodeBOM(6) = 108: bUnicodeBOM(7) = 0: bUnicodeBOM(8) = 108: bUnicodeBOM(9) = 0: bUnicodeBOM(10) = 111: bUnicodeBOM(11) = 0 bUnicode(0) = 72: bUnicode(1) = 0: bUnicode(2) = 101: bUnicode(3) = 0: bUnicode(4) = 108: bUnicode(5) = 0: bUnicode(6) = 108: bUnicode(7) = 0: bUnicode(8) = 111: bUnicode(9) = 0 MsgBox s.Parse(bAnsi) vbCrLf s.Parse(bUnicodeBOM) vbCrLf s.Parse(bUnicode) '顯示Hello in all cases Set s = Nothing Public Function Remove(ByVal Index As Long, ByVal Length As Long) As StringEx '移除指定開始位置，指定數(shù)量的子字符串 Public Function Replace(ByRef SearchString As String, ByRef ReplaceString As String, Optional ByVal Start As Long = 1, Optional ByVal Count As Long = L_NG, Optional ByVal CompareMethod As VbCompareMethod) As StringEx Public Function Split(Optional ByRef Delimeter As String, Optional ByVal Limit As Long = L_NG, Optional ByVal CompareMethod As VbCompareMethod, Optional ByVal ArrayType As VbVarType = vbString) As ArrayEx Public Function Right(ByVal Length As Long) As StringEx Public Function ToArray(Optional ByVal AsANSI As Boolean) As ArrayEx '將字符串轉(zhuǎn)成Byte數(shù)組，AsANSI是true，以ansi碼轉(zhuǎn)換，否則，以u(píng)nicode碼轉(zhuǎn)換。 Dim s As New StringEx MsgBox s.Parse("Hello").ToArray(True).Item(0) '顯示 72 (剩下的分別是 101, 108, 108, 111) Set s = Nothing Public Function ToBoolean() As BooleanEx Public Function ToByte() As ByteEx Public Function ToCurrency() As CurrencyEx Public Function ToDecimal() As DecimalEx Public Function ToDouble() As DoubleEx Public Function ToInteger() As IntegerEx Public Function ToLong() As LongEx Public Function ToSingle() As SingleEx Public Function TrimL() As StringEx Public Function TrimNull() As StringEx Public Function TrimR() As StringEx Public Function Upper() As StringEx DateTime 數(shù)據(jù)類型拓展 : Public Property Get Day() As Integer Public Property Get Hour() As Integer Public Property Get IsLeap() As Boolean Public Property Get Length() As Long Public Property Get Max() As Date Public Property Get Millisecond() As Integer Public Property Get Min() As Date Public Property Get Minute() As Integer Public Property Get Month() As Integer Public Property Get Pointer() As Long Public Property Get Second() As Integer Public Property Get Value() As Date Public Property Let Value(ByVal NewValue As Date) Public Property Get Weekday() As Integer Public Property Get Year() As Integer Public Function AddDays(ByVal Count As Integer) As DateTimeEx Public Function AddHours(ByVal Count As Integer) As DateTimeEx Public Function AddMilliseconds(ByVal Count As Integer) As DateTimeEx Public Function AddMinutes(ByVal Count As Integer) As DateTimeEx Public Function AddMonths(ByVal Count As Integer) As DateTimeEx Public Function AddSeconds(ByVal Count As Integer) As DateTimeEx Public Function AddYears(ByVal Count As Integer) As DateTimeEx Public Function Clone() As DateTimeEx Public Function DateSerial(ByVal Year As Integer, ByVal Month As Integer, ByVal Day As Integer) As DateTimeEx Public Function Now(Optional ByVal UTC As Boolean) As DateTimeEx Public Function Parse(ByRef Value As Variant) As DateTimeEx Public Function TimeSerial(ByVal Hour As Integer, ByVal Minute As Integer, ByVal Second As Integer, Optional ByVal Millisecond As Integer) As DateTimeEx Public Function ToLong() As LongEx Public Function ToString(Optional ByRef Format As String) As StringEx DecimalEx 拓展類 Decimal 平時(shí)隱藏在 variant 下面，所以用的人很少很少。和 double 相比， decimal 類型具有更高的精度和更小的范圍，該類型適用于必須避免舍入錯(cuò)誤的應(yīng)用程序如財(cái)務(wù)、貨幣計(jì)算、金融等。 double 是 64 位的，比 single-32 位精度高 decimal 是 128 位高精度浮點(diǎn)數(shù)，常用于金融運(yùn)算，不會(huì)出現(xiàn)浮點(diǎn)數(shù)計(jì)算的誤差， decimal 類型具有更高的精度和更小的范圍，這使它適合于財(cái)務(wù)和貨幣計(jì)算。注意： decimal 在大多數(shù)情況下是安全的，但浮點(diǎn)數(shù)在理論上是不安全的。 decimal不是基本數(shù)據(jù)類型，所以在所有的數(shù)值計(jì)算中，decimal計(jì)算是最慢的。 Public Property Get Length() As Long ' 返回當(dāng)前 Decimal 值的字節(jié)大小 Public Property Get Max() As Variant ‘ 返回 Decimal 的最大值 Public Property Get Min() As Variant ‘ 返回 Decimal 的最小值 Public Property Get Pointer() As Long ‘ 返回 Decimal 值的指針，注意是值的指針不是 DecimalEX 對(duì)象的指針 Public Property Get Value() As Variant ‘ 返回 Decimal 值默認(rèn)值 Public Property Let Value(ByRef NewValue As Variant) Public Function Clone() As DecimalEx ‘ 新建一個(gè) Decimal 對(duì)象，并深度復(fù)制當(dāng)前 Decimal 對(duì)象。例子： Dim d As New DecimalEx Dim d2 As New DecimalEx d = 0.000008 Set d2 = d.Clone d2 = 1.05555 MsgBox d vbCrLf d2 ' 顯示 0.000008 and 1.05555 Set d = Nothing Set d2 = Nothing Public Function Parse(ByRef Value As Variant) As DecimalEx ‘ 將值轉(zhuǎn)換數(shù)據(jù)類型，并賦值 Dim d As New DoubleEx MsgBox d.Parse("hi115.004") vbCrLf d.Parse(115) vbCrLf d.Parse(345478.0002@) ' 顯示 115.004 ( 非數(shù)字部分自動(dòng)忽略 ), 115 (long 轉(zhuǎn)換成 decimal) and 345478.0002(Currency 轉(zhuǎn)換成 decimal) Public Function Round(ByVal DecimalDigits As Long) As DecimalEx ‘ 對(duì) Decimal 值進(jìn)行十進(jìn)制數(shù)學(xué)上的四舍五入。 DecimalDigits ：保留小數(shù)點(diǎn)后的位數(shù) 例子： Dim d As New DoubleEx MsgBox d.Parse(115.11289).Round(3) ' 顯示 115.113 Set d = Nothing Public Function ToArray() As ArrayEx ‘ 新建一個(gè)數(shù)據(jù)類型是內(nèi)建的 decimal 類型的一維數(shù)組，并將當(dāng)前 decimal 值賦值給數(shù)組的第一元素例子： Dim d As New DecimalEx MsgBox d.Parse("1.0000000005").ToArray.Item(0) ' 顯示 1.0000000005 Set d = Nothing Public Function ToBoolean() As BooleanEx 例子： Dim d As New DecimalEx MsgBox d.Parse("1,0000000005").ToBoolean ' 顯示 True Set d = Nothing Public Function ToByte() As ByteEx 例子： Dim d As New DecimalEx MsgBox d.Parse("1.0000000005").ToByte ' 顯示 1 Set d = Nothing Public Function ToCurrency() As CurrencyEx 例子： Dim d As New DecimalEx MsgBox d.Parse("1.0002000005").ToCurrency ' 顯示 1.0002 Set d = Nothing Public Function ToDouble() As DoubleEx 例子： Dim d As New DecimalEx MsgBox d.Parse("1.0002000111354005").ToDouble ' 顯示 1.0002000111354 Set d = Nothing Public Function ToInteger() As IntegerEx 例子： Dim d As New DecimalEx MsgBox d.Parse("321.0002000111").ToInteger ' 顯示 321 Set d = Nothing Public Function ToLong() As LongEx 例子： Dim d As New DecimalEx MsgBox d.Parse("32146.0002000111").ToLong ' 顯示 32146 Set d = Nothing Public Function ToSingle() As SingleEx 例子： Dim d As New DecimalEx MsgBox d.Parse("32146.02000111").ToSingle ' 顯示 32146.02 Set d = Nothing Public Function ToString(Optional ByRef Format As String) As StringEx ‘ 將當(dāng)前 Decimal 值轉(zhuǎn)換成 String ， Format ：用戶自定義格式，詳見幫助文檔 Format 函數(shù) 例子： Dim d As New DecimalEx MsgBox d.Parse("1234.0000000005").ToString("##,##0.000000000") '顯示 1,234.000000001 Set d = Nothing 待續(xù)…… 我比較擔(dān)心的是，如果使用這樣的數(shù)據(jù)類型拓展類，會(huì)不會(huì)引來(lái)不少人使用上的混亂。因?yàn)槿魏我淮问褂枚急仨? dim 變量 as new StringEX ，使用完之后，必須是 set 變量 =nothing 。如果忘了，如果真的忘了…… , 那老衲有罪呀。; 個(gè)人分類: vb入門|2489 次閱讀|1 個(gè)評(píng)論

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