Using XML as datagridview Source

'Copyright� 2009. Indra Permana Rusli

Imports System.Xml
Imports System.IO

Public Class frmMain
    Private filePath As String = "C:\user.xml" 'xml filepath

#Region " User Defined Function "

    Private Function CreateEmptyTable(ByVal TableName As String, ByVal ParamArray ColumnNames() As String) As Boolean
        Dim writer As New XmlTextWriter(filePath, System.Text.Encoding.UTF8)

        Try
            writer.WriteStartDocument(True)
            writer.Formatting = Formatting.Indented
            writer.Indentation = 2
            writer.WriteStartElement("Table")
            writer.WriteStartElement(TableName)
            For Each ColumnName As String In ColumnNames
                writer.WriteStartElement(ColumnName)
                writer.WriteString(String.Empty)
                writer.WriteEndElement()
            Next
            writer.WriteEndElement()
            writer.WriteEndElement()
            writer.WriteEndDocument()
            writer.Close()
        Catch ex As Exception
            MsgBox("Cannot create new table.")
            Return False
        End Try

        Return True
    End Function

    Private Function FormatDgvMstUser(ByRef ObjDgv As DataGridView) As Boolean
        Dim cUsername As New DataGridViewTextBoxColumn
        Dim cPassword As New DataGridViewTextBoxColumn

        cUsername.Name = "user_name"
        cUsername.HeaderText = "Username"
        cUsername.Width = 100
        cUsername.DataPropertyName = "user_name"
        cUsername.Visible = True
        cUsername.ReadOnly = False

        cPassword.Name = "user_password"
        cPassword.HeaderText = "Password"
        cPassword.Width = 100
        cPassword.DataPropertyName = "user_password"
        cPassword.Visible = True
        cPassword.ReadOnly = False

        Try
            ObjDgv.Columns.Clear()
            ObjDgv.Columns.AddRange(New DataGridViewColumn() {cUsername, cPassword})
            ObjDgv.AllowUserToAddRows = True
        Catch ex As Exception
            MsgBox("Cannot format datagridview.")
            Return False
        End Try

        Return True
    End Function

#End Region

    Private Sub frmMain_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim xmlFile As XmlReader
        Dim ds As New DataSet

        'if file doesn't exist, create the file with its default xml table
        If Not File.Exists(filePath) Then
            If Not Me.CreateEmptyTable("User", "user_name", "user_password") Then End
        End If

        'fill dataset with selected xml table
        xmlFile = XmlReader.Create(filePath, New XmlReaderSettings())
        ds.ReadXml(xmlFile)
        xmlFile.Close()

        'init datagridview
        Me.DgvMstUser.DataSource = ds.Tables(0)
        If Not Me.FormatDgvMstUser(Me.DgvMstUser) Then End
    End Sub

    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
        Dim dt As New DataTable

        Me.DgvMstUser.EndEdit()
        dt = Me.DgvMstUser.DataSource

        Try
            dt.WriteXml(filePath)
            MsgBox("Data has been saved.")
        Catch ex As Exception
            MsgBox("Data cannot be saved.")
        End Try
    End Sub
End Class