Dim 变量名 as 类型 '定义为局部变量,如 Dim ebookit as integer Private 变量名 as 类型 '定义为私有变量,如 Private ebookit as byte Public 变量名 as 类型 '定义为公有变量,如 Public ebookit as single Global 变量名 as 类型 '定义为全局变量,如 Globlal ebookit as date Static 变量名 as 类型 '定义为静态变量,如 Static ebookit as double
一般变量作用域的原则是,那部份定义就在那部份起作用,模块中定义则在该模块那作用。
4:常量为变量的一种特例,用Const定义,且定义时赋值,程序中不能改变值,作用域也如同变量作用域。如下定义:Const Pi=3.1415926 as single
二:判断语句
1:If…Then…Else语句 If condition Then [statements][Else elsestatements] 如①:If A>B And C<D Then A=B+2 Else A=C+2 如②:If x>250 Then x=x-100 或者,可以使用块形式的语法:
If condition Then [statements] [ElseIf condition-n Then [elseifstatements] ... [Else [elsestatements]] End If
如1: If Number < 10 Then Digits = 1 ElseIf Number < 100 Then Digits = 2 Else Digits = 3 End If
2:Select Case…Case…End Case语句 如1: Select Case Pid Case “A101” Price=200 Case “A102” Price=300 …… Case Else Price=900 End Case
1:For Next语句 以指定次数来重复执行一组语句 For counter = start To end [Step step] ' step 缺省值为1 [statements] [Exit For] [statements] Next [counter] 如1: For Words = 10 To 1 Step -1 ' 建立 10 次循环 For Chars = 0 To 9 ' 建立 10 次循环 MyString = MyString & Chars ' 将数字添加到字符串中 Next Chars ' Increment counter MyString = MyString & " " ' 添加一个空格 Next Words
2:For Each…Next语句 主要功能是对一个数组或集合对象进行,让所有元素重复执行一次语句 For Each element In group Statements [Exit for] Statements Next [element]
如1: For Each rang2 In range1 With range2.interior .colorindex=6 .pattern=xlSolid End with Next 这上面一例中用到了 With…End With 语句,目的是省去对象多次调用,加快速度;语法为: With object [statements] End With
3:Do…loop语句 在条件为true时,重复执行区块命令
Do {while |until} condition ' while 为当型循环,until为直到退出循环条件 Statements Exit do Statements Loop
或者使用下面语法 Do ' 先do 再判断 Statements Exit do Statements Loop {while |until} condition