1. ASC(X)，Chr(X)：转换字符字符码
[格式]：
P=Asc(X) 返回字符串X的第一个字符的字符码
P=Chr(X) 返回字符码等于X的字符
[范例]：
(1)P=Chr(65)
‘ 输出字符A,因为A的ASCII码等于65
(2)P=Asc(“A”)
‘ 输出65
2. Len(X)： 计算字符串X的长度
[格式]：
P=Len(X)
[说明]：
空字符串长度为0，空格符也算一个字符，一个中文字虽然占用2 Bytes，但也算一个字符。
[范例]：
(1) 令X=”” (空字符串)
Len(X) 输出结果为0
(2) 令X=”abcd”
Len(X) 输出结果为4
(3) 令X=”VB教程”
Len(X) 输出结果为4
3. Mid(X)函数：读取字符串X中间的字符
[格式]：
......
'创建快捷方式，兼容vista
'要把vb6stkit.DLL放到程序目录
'敖士伟 09-10-27
'只对“桌面”和“开启”有效，其它还没做
'=========开启外部同步程序定义开始
Const SYNCHRONIZE = &H100000
Const INFINITE = &HFFFF 'Wait forever
Const WAIT_OBJECT_0 = 0 'The state of the specified object is signaled.
Const WAIT_TIMEOUT = &H102 'The time-out interval elapsed, and the
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
'=========开启外部同步程序定义结束
'创建快捷方式
Private Declare Function fCreateShellLink Lib "vb6stkit.DLL" ( _
ByVal lpstrFolderName As String, _
ByVal lpstrLinkName As String, _
ByVal lpstrLinkPath As String, _
ByVal lpstrLinkArgs A ......
一。数据类型
Byte 1
字节 无符号
Interger 2
字节
Long 4
字节
Float 4
字节
Double 8
字节
String
Date
Boolean
Currency
Variant
2.
变长字符串和定长字符
系统默认初始值为空字符串;
变长字符串：dim str as Strring
定长字符串:dim str as String*30
最多64K
字符
3.
逻辑型数据
系统默认为False;
当布尔型转为整形时 True
为-1 False
为0;
其它型转化为布尔型
非0
为True 0
为False;
4.
日期型数据
文字日期包含在一对“#"
之间，如#4 Sep# #May
23.2002#
等;
在日期型数据中，不论将年、月、日如何排列，用何种分隔符，系统会自动将其转化为由数字表示的”
月/
日/
年“
5
。对象类型
默认值为nothing
，用SET
语句指定一个声明的对象变量去引用对象。
6.
变体类型
所有未定义的变量的默认类型。用VarType
（）返回的值可以确定具体数据类型。
二。常量
三种：直接常量（字面值），自定义符号常量，系统常量
（1
）自定义符号常量
Const
符号常量名 ......
目的掌握一个简单的VB程序的建立、编辑、调试、运行和保存的方法。
操作步骤 ⑴进入VB环境，新建工程。方法是：如果出现“新建工程”对话框，则选择“标准.EXE”并点击[打开]按纽；或者直接点击菜单[文件]-[新建工程]。都会出现一个名为“Form1”的新窗体。
⑵从标准控件工具栏中向窗体加入标签(Label1和Label2)、两个命令按纽(Command1和Command2)。
⑶由于标准控件工具仅提供20个内部控件，实际上vb程序中还可加入ActiveX控件和可插入对象等。为此本次实验请试用以下方法加入“滑块”控件，加入前必须使用菜单[工程]-[部件]，然后从弹出的列表框中勾选“Microsoft Windows Common Control 6.0 ”并点击[确定]按纽，然后就可以从控件工具栏中加入一个名为“Slider”的滑块控件了。
⑷设置窗体的背景图像、命令按纽的Picture属性和两个标签上的文字和字体后等属性： 控件名 属性和属性值 Form1 Caption=”初识VB世界”Picture=” BJtu.bmp” Label1 Caption=”新年快乐” Font 隶书 36 黑色 Left=400 BackStyle 透明 Label2 Caption=”新年快乐” Fon ......
Private Sub Command1_Click()
Dim dso As New XMLDSOControl
Dim doc As IXMLDOMDocument
Set doc = dso.XMLDocument
Dim rel As IXMLDOMNodeList
Set x = CreateObject("Microsoft.XMLHTTP")
x.Open "GET", "http://127.0.0.1:8080/emrb/Mrbmodel?action=dis&userid=11&authority=111
", False
x.send
doc.Load (x.responseXML)
Set Tablelist = doc.getElementsByTagName("record")
Tablelen = Tablelist.length
For i = 0 To (Tablelen - 1)
'Text1.Text = Tablelist.Item(i).selectSingleNode("Fremark").Text
Combo1.AddItem (Tablelist.Item(i).selectSingleNode("pn").Text)
Next
End Sub
Private Sub Command2_Click()
a = "<result><TD>A
AAAA%AAAA</TD><TD>AAAAAA
AAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD&g ......
Private Sub Command1_Click()
Dim dso As New XMLDSOControl
Dim doc As IXMLDOMDocument
Set doc = dso.XMLDocument
Dim rel As IXMLDOMNodeList
Set x = CreateObject("Microsoft.XMLHTTP")
x.Open "GET", "http://127.0.0.1:8080/emrb/Mrbmodel?action=dis&userid=11&authority=111
", False
x.send
doc.Load (x.responseXML)
Set Tablelist = doc.getElementsByTagName("record")
Tablelen = Tablelist.length
For i = 0 To (Tablelen - 1)
'Text1.Text = Tablelist.Item(i).selectSingleNode("Fremark").Text
Combo1.AddItem (Tablelist.Item(i).selectSingleNode("pn").Text)
Next
End Sub
Private Sub Command2_Click()
a = "<result><TD>A
AAAA%AAAA</TD><TD>AAAAAA
AAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD>AAAAAAAAA</TD><TD&g ......
Function crypt(Action As String, Key As String, Src As String) As String
'Action
' E encrypts, D decrypts,
'Key is a unique string needed to en/decrypt (either
' hardcode or setup something for the user to enter.
'Src is the string to be en/decrypted.
On Error GoTo errHandler
Dim count As Integer, KeyPos As Integer, KeyLen As Integer, SrcAsc As Integer
Dim Dest As String, Offset As Integer, TmpSrcAsc, SrcPos As Integer
KeyLen = Len(Key)
If Action = "E" Then
Randomize
Offset = (Rnd * 10000 Mod 255) + 1
Dest = Hex$(Offset)
For SrcPos = 1 To Len(Src)
SrcAsc = (Asc(Mid$(Src, SrcPos, 1)) + Offset) Mod 255
If KeyPos < KeyLen Then KeyPos = KeyPos + 1 Else KeyP ......
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