在客户端执行数据库记录的分页显示

创建一个分页类

　　要记住，这里举例的整个应用程序只包括一个ASP页面。当这个ASP页面被访问时，它将创建执行记录分页需要的所有客户端JavaScript代码。为简化这个过程，我创建了一个VBScript类来处理这个功能。使用这个类的时候，开发人员只需将他希望在访问者的Web浏览器上进行分页的记录集传递进来即可。关于类的使用，请阅读在VBScript中使用类。

　　我将这个类命名为dhtmlGetRows，它包含两个属性和一个方法。两个属性是：

　　1、 RecsPerPage：确定每一页显示多少个记录。

　　2、 THString：通过一个HTML表格显示这个进行了分页的结果；这个属性允许你为表格的标题指定一个字串。

　　单一的方法是GenerateHTML(RecordsetObject)，它为分页应用程序返回完整的HTML：客户端JavaScript代码和需要的DIV 标记。这个方法只需要一个参数RecordsetObject，它应该是一个记录集对象，其中填充了你希望在一个分页格式中显示的数据库数据。

　　这个类的代码相当长，并且大部分代码都只是返回客户端的JavaScript代码。下面是类的代码：

＜% Class dhtmlGetRows '******* PRIVATE MEMBER VARIABLES ********** Private iRecsPerPage Private strTHString '******************************************* '************ Initialize Event ************* Private Sub Class_Initialize() iRecsPerPage = 10 'assign a default value End Sub '******************************************* '************ PROPERTY LET/GET ************* Public Property Let THString(strValue) 'Replace all apostrophes with \' strTHString = Replace(strValue, "'", "\'") End Property Public Property Get THString() THString = strTHString End Property Public Property Let RecsPerPage(iValue) If iValue ＞ 0 and IsNumeric(iValue) then iRecsPerPage = CInt(iValue) End If End Property Public Property Get RecsPerPage() RecsPerPage = iRecsPerPage End Property '******************************************* '**************** METHODS ****************** Public Function GenerateHTML(objRS) 'Begin by getting an array of the data Dim aValues aValues = objRS.GetRows() 'Find the value of rows and columns Dim iCols, iRows iCols = UBound(aValues, 1) iRows = UBound(aValues, 2) Dim strOutput 'Display the initial script block strOutput = "＜script language=""javascript""＞" & vbCrLf & _ "var tableRow = new Array(" & iRows & ");" & vbCrLf & vbCrLf Dim iLoop, iColLoop, strTmp For iLoop = 0 to iRows strOutput = strOutput & "tableRow[" & iLoop & "] = '＜tr＞" For iColLoop = 0 to iCols 'Fix apostrophes strTmp = Replace(aValues(iColLoop, iLoop),"'", "\'") 'Remove carraige returns strTmp = Replace(strTmp, vbCrLf, "") strOutput = strOutput & "＜td＞" & strTmp & "＜/td＞" Next 'iColLoop strOutput = strOutput & "＜/tr＞';" & vbCrLf Next 'iLoop 'Init global varaibles and find out what browser the user is using strOutput = strOutput & vbCrLf & vbCrLf & "var first = 0;" & vbCrLf & _ "var last = " & iRecsPerPage & ";" & vbCrLf & _ "var mynav;" & vbCrLf & "if (navigator.appName == ""Netscape"")" & _ vbCrLf & vbTab & "mynav = ""NS"";" & vbCrLf & _ "if (navigator.appName == ""Microsoft Internet Explorer"")" & _ vbCrLf & vbTab & "mynav = ""IE"";" & vbCrLf & _ vbCrLf & "＜/script＞" & vbCrLf & vbCrLf 'Now display the HTML table strOutput = strOutput & vbCrLf & "＜div id=""grid""＞ ＜/div＞" & vbCrLf & _ vbCrLf & vbCrLf & "＜script language=""javascript""＞" & vbCrLf 'Write the nav function strOutput = strOutput & "function nav(iVal) {" & vbCrLf & _ "// do we want to move forward or backwards?" & vbCrLf & _ "if (iVal == 1) { " & vbCrLf & vbTab & "first += " & _ iRecsPerPage & ";" & vbCrLf & "last += " & iRecsPerPage & _ vbCrLf & "}" & vbCrLf & "else if (iVal == -1) { " & vbCrLf & vbTab & _ "first -= " & iRecsPerPage & ";" & vbCrLf & vbTab & "last -= " & _ iRecsPerPage & ";" & vbCrLf & "}" & vbCrLf & _ vbCrLf & vbCrLf & "var txt = '';" & vbCrLf & _ "txt += '＜table border=""1""＞';" & vbCrLf 'Do we need to add a TH string? If Len(strTHString) ＞ 0 then strOutput = strOutput & "txt += '＜tr＞" & strTHString & "＜/tr＞';" & vbCrLf End If strOutput = strOutput & "for (var iLoop = first; iLoop ＜ last; iLoop++)" & vbCrLf & _ vbTab & "if (iLoop ＜= " & iRows & ") txt += tableRow[iLoop];" & vbCrLf & _ "txt += '＜/table＞';" & vbCrLf & vbCrLf 'Now, show next/prev links if applicable strOutput = strOutput & "if (first ＞ 0) // show prev link" & vbCrLf & _ vbTab & "txt += '＜a href=""javascript:nav(-1);""＞Prev " & _ iRecsPerPage & "＜/a＞ ';" & vbCrLf & vbCrLf & _ "if (last ＜= " & iRows & ") // show next link" & vbCrLf & vbTab & _ "txt += '＜a href=""javascript:nav(1);""＞Next " & _ iRecsPerPage & "＜/a＞';" & vbCrLf & vbCrLf 'Write out the new HTML content to the DIV tag strOutput = strOutput & "// write out the the DIV tag depending on browser..." & vbCrLf & _ "if (mynav == ""NS"") {" & vbCrLf & vbTab & _ "document.layers['grid'].document.write(txt);" & vbCrLf & vbTab & _ "document.close();" & vbCrLf & "}" & vbCrLf & vbCrLf & _ "if (mynav == ""IE"")" & vbCrLf & vbTab & _ "document.all['grid'].innerHTML = txt;" & vbCrLf & vbCrLf & _ "}" & vbCrLf & vbCrLf strOutput = strOutput & "nav(0);" & vbCrLf & "＜/script＞" GenerateHTML = strOutput End Function '******************************************* End Class %＞