A sample of operating XML data in ASP.NET 2.0(VB.NET)

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A sample of operating XML data in ASP.NET 2.0(VB.NET)

ASP.NET Database Tutorial

Microsoft .NET introduces a new suite of XML APIs built on industry standards such as DOM, XPath, XSD, and XSLT. The .NET Framework XML classes also offer convenience, better performance, and a more familiar programming model, tightly coupled with the new .NET data access APIs—ADO .NET. XmlWriter, XmlReader, and XmlNavigator classes and classes that derive from them, including XMLTextReader and XMLTextWriter, encapsulate a number of functionalities that previously had to be accomplished manually. This tutorial will show you a sample of how to operate XML in ASP.NET and VB.NET.

The System.Xml namespace contains the XmlDocument Class .we can use this class to operate xml file.

At first, import the namespace of System.Xml and System.Data

Imports System.Xml
Imports System.Data

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Add four buttons to web page, Add, modify, Delete and Clear

Add 2 functions: One is loadXmlData, and the other is FindXmlData

//insert data to xml file

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim xmldoc As XmlDocument = New XmlDocument()
xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))

Dim newelement As XmlElement = xmldoc.CreateElement("poems")
Dim xmlAuthor As XmlElement = xmldoc.CreateElement("author")
Dim xmlTitle As XmlElement = xmldoc.CreateElement("title")
Dim xmlContent As XmlElement = xmldoc.CreateElement("content")

xmlAuthor.InnerText = Me.TextBox1.Text.Trim()
xmlTitle.InnerText = Me.TextBox2.Text.Trim()
xmlContent.InnerText = Me.TextBox3.Text.Trim()

newelement.AppendChild(xmlAuthor)
newelement.AppendChild(xmlTitle)
newelement.AppendChild(xmlContent)

xmldoc.DocumentElement.AppendChild(newelement)
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))

loadXmlData()
End Sub

//modify one xml data base on selecteditem

Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim xmldoc As XmlDocument = New XmlDocument()

xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
If Int32.Parse(Me.lblSelectIndex.Text) = -1 Then
Me.RegisterClientScriptBlock("alertmessage", "<script>alert('please select one modify data item.')</script>")
Else
Dim xmlnode As XmlNode = xmldoc.DocumentElement.ChildNodes.Item(Int32.Parse(Me.lblSelectIndex.Text))
xmlnode("author").InnerText = Me.TextBox1.Text.Trim()
xmlnode("title").InnerText = Me.TextBox2.Text.Trim()
xmlnode("content").InnerText = Me.TextBox3.Text.Trim()
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))
End If
loadXmlData()
End Sub

//Delete one xml data base on selecteditem

Protected Sub Button3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim xmldoc As XmlDocument = New XmlDocument()
xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
Dim xmlnode As XmlNode = xmldoc.DocumentElement.ChildNodes.Item(Int32.Parse(Me.lblSelectIndex.Text))
xmlnode.ParentNode.RemoveChild(xmlnode)
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))
loadXmlData()
Me.TextBox1.Text = ""
Me.TextBox2.Text = ""
Me.TextBox3.Text = ""
End Sub

//clear textbox value

Protected Sub Button4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button4.Click
Me.TextBox1.Text = ""
Me.TextBox2.Text = ""
Me.TextBox3.Text = ""
End Sub

//load xml data from xml file

Private Sub loadXmlData()
Dim myDs As DataSet = New DataSet()
myDs.ReadXml(Server.MapPath("App_Data\smallfools.xml"))

If myDs.Tables.Count <> 0 Then
Me.GridView1.DataSource = myDs
Me.GridView1.DataBind()
End If

End Sub

//select one data and fill data to textbox

Private Sub FindXmlData(ByVal selectedIndex As Integer)
Dim xmldoc As XmlDocument = New XmlDocument()

xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
Dim xmlnodelist As XmlNodeList = xmldoc.DocumentElement.ChildNodes
Dim xmlnode As XmlNode = xmlnodelist.Item(selectedIndex)
Me.textBox1.Text = xmlnode("author").InnerText
Me.textBox2.Text = xmlnode("title").InnerText
Me.textBox3.Text = xmlnode("content").InnerText
End Sub

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The front page of Default.aspx:

<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_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 id="Head1" runat="server">
<title>Default</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<fieldset style="height: 401px">
<legend>Operate Xml</legend>author: 
<asp:TextBox ID="TextBox1" runat="server" Width="231px"></asp:TextBox><br />
title:     
<asp:TextBox ID="TextBox2" runat="server" Width="231px"></asp:TextBox><br />
content:<asp:TextBox ID="TextBox3" runat="server" Width="231px"></asp:TextBox>
<asp:Label ID="lblSelectIndex" runat="server" Visible="False"></asp:Label><br />
<asp:Button ID="Button1" runat="server" Text="Add" />
<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="modify" />
<asp:Button ID="Button3" runat="server" Text="Delete" />
<asp:Button ID="Button4" runat="server" OnClick="Button4_Click" Text="Clear" /><br />
<br />
<asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"
OnSelectedIndexChanged="GridView1_SelectedIndexChanged" Width="428px" AutoGenerateColumns="False">
<FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
<Columns>
<asp:CommandField CancelText="Cancel" DeleteText="Delete" EditText="Modify" InsertText="Insert"
NewText="New" SelectText="Select" ShowSelectButton="True" UpdateText="Update" />
<asp:BoundField DataField="author" HeaderText="Author" />
<asp:BoundField DataField="title" HeaderText="Tilte" />
<asp:BoundField DataField="content" HeaderText="Content" />
</Columns>
<RowStyle BackColor="#E3EAEB" />
<EditRowStyle BackColor="#7C6F57" />
<SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
<PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
<HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
</fieldset>

</div>
</form>
</body>
</html>

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The code behind the front page as follows

Imports System.Xml
Imports System.Data

Partial Class _Default
Inherits System.Web.UI.Page
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.Load
If Me.IsPostBack = False Then
loadXmlData()
End If
End Sub
Private Sub loadXmlData()
Dim myDs As DataSet = New DataSet()
myDs.ReadXml(Server.MapPath("App_Data\smallfools.xml"))

If myDs.Tables.Count <> 0 Then
Me.GridView1.DataSource = myDs
Me.GridView1.DataBind()
End If

End Sub

Protected Sub GridView1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles GridView1.SelectedIndexChanged
Me.lblSelectIndex.Text = Me.GridView1.SelectedIndex.ToString()
If Me.lblSelectIndex.Text.Equals("") Then
FindXmlData(Int32.Parse(Me.lblSelectIndex.Text))
End If
End Sub
Private Sub FindXmlData(ByVal selectedIndex As Integer)
Dim xmldoc As XmlDocument = New XmlDocument()

xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
Dim xmlnodelist As XmlNodeList = xmldoc.DocumentElement.ChildNodes
Dim xmlnode As XmlNode = xmlnodelist.Item(selectedIndex)
Me.textBox1.Text = xmlnode("author").InnerText
Me.textBox2.Text = xmlnode("title").InnerText
Me.textBox3.Text = xmlnode("content").InnerText
End Sub

Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim xmldoc As XmlDocument = New XmlDocument()

xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
If Int32.Parse(Me.lblSelectIndex.Text) = -1 Then
Me.RegisterClientScriptBlock("alertmessage", "<script>alert('please select one modify data item.')</script>")
Else
Dim xmlnode As XmlNode = xmldoc.DocumentElement.ChildNodes.Item(Int32.Parse(Me.lblSelectIndex.Text))
xmlnode("author").InnerText = Me.TextBox1.Text.Trim()
xmlnode("title").InnerText = Me.TextBox2.Text.Trim()
xmlnode("content").InnerText = Me.TextBox3.Text.Trim()
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))
End If
loadXmlData()
End Sub

Protected Sub Button4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button4.Click
Me.TextBox1.Text = ""
Me.TextBox2.Text = ""
Me.TextBox3.Text = ""
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim xmldoc As XmlDocument = New XmlDocument()
xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))

Dim newelement As XmlElement = xmldoc.CreateElement("poems")
Dim xmlAuthor As XmlElement = xmldoc.CreateElement("author")
Dim xmlTitle As XmlElement = xmldoc.CreateElement("title")
Dim xmlContent As XmlElement = xmldoc.CreateElement("content")

xmlAuthor.InnerText = Me.TextBox1.Text.Trim()
xmlTitle.InnerText = Me.TextBox2.Text.Trim()
xmlContent.InnerText = Me.TextBox3.Text.Trim()

newelement.AppendChild(xmlAuthor)
newelement.AppendChild(xmlTitle)
newelement.AppendChild(xmlContent)

xmldoc.DocumentElement.AppendChild(newelement)
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))

loadXmlData()
End Sub

Protected Sub Button3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim xmldoc As XmlDocument = New XmlDocument()
xmldoc.Load(Server.MapPath("App_Data\smallfools.xml"))
Dim xmlnode As XmlNode = xmldoc.DocumentElement.ChildNodes.Item(Int32.Parse(Me.lblSelectIndex.Text))
xmlnode.ParentNode.RemoveChild(xmlnode)
xmldoc.Save(Server.MapPath("App_Data\smallfools.xml"))
loadXmlData()
Me.TextBox1.Text = ""
Me.TextBox2.Text = ""
Me.TextBox3.Text = ""
End Sub
End Class

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