How can I sort a Table into ascending or descending? VB.NET
I am currently building a table by retrieving a number and a name from an XML document and dynamically building a table. Currently, the table is built and you can check a box to choose whether or not you want to randomize the numbers that correspond to the name. I need to be able to check another box to determine whether or not you want it ascending or descending order. I don't know how to do sorts on a Table Object. Do I have to read it into an Array first and then re-read them into the table?
XML Document Example:
- <roster>
- <student>
<order>01</order>
<name>Sabrina Spark</name>
</student>
- <student>
<order>02</order>
<name>Ryan Weble</name>
</student>
- <student>
<order>03</order>
<name>Fredric Scott</name>
</student>
- <student>
<order>04</order>
<name>Cory Snyder</name>
</student>
Code:
Markup:<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="itc320_presentation_order._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<link href="StyleSheet1.css" rel="Stylesheet" type = "text/css" media = "scree开发者_C百科n" />
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:CheckBox ID="Descending" runat="server" Text="Descending" />
<asp:CheckBox ID="ExistingOrder" runat="server" Text="Existing Order" />
<br />
<asp:Xml ID="Xml1" runat="server"></asp:Xml>
<br />
<asp:XmlDataSource ID="XmlDataSource1" runat="server"
DataFile="~/App_Data/roster.xml" TransformFile="~/App_Data/roster.xsl">
</asp:XmlDataSource>
<br />
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
<br />
<br />
<asp:Button ID="cmdRandomize" runat="server" Height="36px" Text="Generate Table"
Width="127px" />
<br />
</div>
</form>
</body>
</html>
Code Behind :
Imports System.Xml
Imports System.IO
Partial Public Class _Default
Inherits System.Web.UI.Page
Dim rand As New Random()
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
End If
End Sub
Protected Sub cmdRandomize_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cmdRandomize.Click
Dim intArl(15) As Integer
Dim ds As DataSet
Dim dr As DataRow
Dim tbl As New Table
Dim strPath As String
'Placehold control will hold the dynamically created table
PlaceHolder1.Controls.Clear()
'build path to data file
strPath = Server.MapPath("/App_Data") & "\roster.xml"
ds = New DataSet()
'load dataset object with data from xml source
ds.ReadXml(strPath)
Dim dtRoster As DataTable = ds.Tables(0)
'Generate table of random order ints
If ExistingOrder.Checked = False Then
genUnique(intArl, dtRoster.Rows.Count - 1)
Else
intArl = ViewState("intArl")
End If
Dim intSeq As Integer = 0
For Each dr In dtRoster.Rows
Dim tr As New TableRow
For intColCnt = 0 To 1
Dim tc As New TableCell()
Dim txtBox As New TextBox()
If intColCnt = 0 Then
txtBox.Text = intSeq
Else
txtBox.Text = dr(intColCnt)
End If
'Add the control to the TableCell
tc.Controls.Add(txtBox)
'Add the TableCell to the TableRow
tr.Cells.Add(tc)
Next
If intSeq Mod 2 Then
tr.CssClass = "odd"
Else
tr.CssClass = "even"
End If
tbl.Rows.Add(tr)
intSeq += 1
Next
PlaceHolder1.Controls.Add(tbl)
ViewState("intArl") = intArl
End Sub
Private Sub genUnique(ByRef intArl() As Integer, ByVal intCnt As Integer)
Dim intGen As Integer
Dim intClassCnt As Integer
For intClassCnt = 0 To intCnt
regen:
'intGen = Int(Rnd() * 20) + 1
intGen = rand.Next(1, intCnt + 2)
If Not alreadyExists(intArl, intGen, intClassCnt) Then
intArl(intClassCnt) = intGen
Else : GoTo regen
End If
Next
End Sub
Private Function alreadyExists(ByRef intArl() As Integer, ByVal num As Integer, ByVal curr As Integer) As Boolean
Dim intCnt As Integer
'Scan the entries in the array for the existance of the newly
'generated number. Return True if found to already exist in the array
For intCnt = 0 To curr - 1
If num = intArl(intCnt) Then
Return True
End If
Next
Return False
End Function
End Class
You're going to want to sort the DataTable before your loop.
http://www.akadia.com/services/dotnet_filter_sort.html#Filtering%20and%20Sorting%20with%20the%20DataTable%20Select%20Method
Since you are programmatic generating the table it can't be sorted as such. You can easily sort your data table and then regenerate your table. Another option would be to use one of the available data controls DataGridview for example which handle the job of generation for you and in some cases allow you to add sorting in the designer.
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