GuestBook Using XML Database in ASP.NET

Introduction

Most of the websites uses XML Database for the sections like Guestbook, Comments, and Feedbacks even in many Forums XML Databases are used. To be very frank, when I was learning XML, I created many XML files and integrated it to HTML web pages but when I learnt ASP.Net I thought to integrate it in ASP.Net also. I faced lots of problems like how to create XML files at run time, how to create columns in XML file at run time, how to connect it to ASP.Net so that visitors can input some text in XML file. On that time, there were lots of such questions in my mind. But my friend it is really very-very easy to work with XML files. Let's take a look at some basic points.

Prerequisite

To learn this article, you must have some basic understanding of XML Database.

Creating XML File at run time

To create XML at run time, we must check its existence first and if not finds then will create a new one. To do this we have to integrate all in Page Load event. Let's take a look how it is?

Sub Page_Load(Src As Object, E As EventArgs)

'Checking the existance of XML database
strFilePath = Server.MapPath("guestbook.xml")

'If XML database not exit then it creates a new XML database
'using other functions given below
If Not Page.IsPostBack Then

'If XML file not exists, create a new one
If Not File.Exists(strFilePath) Then
InitializeXMLFile()
End If
'If XML database exist then runs it
PopulateDataSet()
DisplayData()
End If
End Sub

Above coding will fist check its existence using file name 'guestbook.xml' and if not finds then it will create a new one. Let's take a look how it is?

Sub InitializeXMLFile()
'Create a new data-set
myDataSet = New DataSet()

'Create a new data-table
Dim myTable As DataTable = myDataSet.Tables.Add("myguestbook")

'Define column id, it will not be visible on form page
Dim myDataColumn as DataColumn = myTable.Columns.Add("id", Type.GetType("System.Int32"))
With myDataColumn
.AutoIncrement = true
.AutoIncrementSeed = 1
.AutoIncrementStep = 1
End With

'Seting column named id as the primary key
Dim arrPrimaryKey(1) As DataColumn
arrPrimaryKey(0) = myDataColumn
myTable.PrimaryKey = arrPrimaryKey

'Defining other columns which will be visible on form
myTable.Columns.Add("datetime", Type.GetType("System.DateTime"))
myTable.Columns.Add("name", Type.GetType("System.String"))
myTable.Columns.Add("email", Type.GetType("System.String"))
myTable.Columns.Add("comments", Type.GetType("System.String"))

'Writing table structure in XML file which is defined above
myDataSet.WriteXml(strFilePath, XMLWriteMode.WriteSchema)
End Sub

Above coding will created new XML Database with Data Table named 'myguestbook'. Now we have to populate it for use. Let's take a look how it is?

Sub PopulateDataSet()
myDataSet = New DataSet()
myDataSet.ReadXml(strFilePath, XmlReadMode.ReadSchema)
End Sub

Above coding will populated the XML Database file for use as 'Read Only' Property. Now we have to display its data on web page. Let's take a look how it is?

Sub DisplayData()
'Bind data to Repeater
Dim myDataView As DataView = myDataSet.Tables(0).DefaultView

'Uncomment next line to display the newer messages first
myDataView.Sort = "id DESC"

myRepeater.DataSource = myDataView
myRepeater.DataBind()
End Sub

In above coding, we are displaying the data in descending order. Now we have to create web page and connect it to XML file. In web page we should have three controls for date and time, name and email id and a command button to insert data in XML file. Let's take a look to create web page with controls.

<table style="width: 226px" bgcolor="#dcdcdc">
<tr>
<td>Name</td>
<td style="width: 292px"><asp:textbox id="txtEmail" runat="server" columns="30"maxlength="30" Width="264px" /></td>
<td style="width: 134217727px" align="left" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
ErrorMessage="RequiredFieldValidator" ControlToValidate="txtEmail">*</asp:RequiredFieldValidator></td>
</tr>
<tr>
<td>Email</td>
<td style="width: 292px"><asp:textbox id="txtName" runat="server" columns="50"maxlength="50" Width="263px" /></td>
<td style="width: 134217727px" align="left" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server"
ErrorMessage="RequiredFieldValidator" ControlToValidate="txtName">*</asp:RequiredFieldValidator><br />
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server"
ErrorMessage="RegularExpressionValidator" ControlToValidate="txtName"
ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*">*</asp:RegularExpressionValidator></td>
</tr>
<tr>
<td valign="top">Comments</td>
<td style="width: 292px"><asp:textbox id="txtComments" runat="server"columns="30" rows="4" textmode="multiline" wrap="true" /></td>
<td style="width: 134217727px" align="left" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server"ErrorMessage="RequiredFieldValidator"ControlToValidate="txtComments">*</asp:RequiredFieldValidator></td>
</tr>
<tr>
<td colspan="2" align="right"><asp:button id="btnSubmit" text="Submit"onclick="btnSubmit_Click" runat="server" /></td>
<td align="left" colspan="1" style="width: 134217727px" valign="top">
</td>
</tr>
</table>