Sql Server Database Backup and Restore through VB.net

First you have to add some namespace in your vb file:
Imports Microsoft.SqlServer.management
Imports Microsoft.SqlServer.Management.NotificationServices
Imports Microsoft.SqlServer.Management.Smo
Imports Microsoft.SqlServer.Management.Smo.Agent
Imports Microsoft.SqlServer.Management.Smo.Broker
Imports Microsoft.SqlServer.Management.Smo.Mail
Imports Microsoft.SqlServer.Management.Smo.RegisteredServers
Imports Microsoft.SqlServer.Management.Smo.Wmi
Imports Microsoft.SqlServer.Management.Trace

'Code for backup database

Public Sub BackupDatabase(databaseName As String, userName As String, password As [String], serverName As [String], destinationPath As [String])
 Dim sqlBackup As New Backup()

 sqlBackup.Action = BackupActionType.Database
 sqlBackup.BackupSetDescription = "ArchiveDataBase:" & DateTime.Now.ToShortDateString()
 sqlBackup.BackupSetName = "Archive"

 sqlBackup.Database = databaseName

 Dim deviceItem As New BackupDeviceItem(destinationPath, DeviceType.File)
 Dim connection As New ServerConnection(serverName, userName, password)
 Dim sqlServer As New Server(connection)

 Dim db As Database = sqlServer.Databases(databaseName)

 sqlBackup.Initialize = True
 sqlBackup.Checksum = True
 sqlBackup.ContinueAfterError = True

 sqlBackup.Devices.Add(deviceItem)
 sqlBackup.Incremental = False

 sqlBackup.ExpirationDate = DateTime.Now.AddDays(3)
 sqlBackup.LogTruncation = BackupTruncateLogType.Truncate

 sqlBackup.FormatMedia = False

 sqlBackup.SqlBackup(sqlServer)
End Sub

'Code for restoration od database:

Public Sub RestoreDatabase(databaseName As [String], filePath As [String], serverName As [String], userName As [String], password As [String], dataFilePath As [String], _
 logFilePath As [String])
 Dim sqlRestore As New Restore()

 Dim deviceItem As New BackupDeviceItem(filePath, DeviceType.File)
 sqlRestore.Devices.Add(deviceItem)
 sqlRestore.Database = databaseName

 Dim connection As New ServerConnection(serverName, userName, password)
 Dim sqlServer As New Server(connection)

 Dim db As Database = sqlServer.Databases(databaseName)
 sqlRestore.Action = RestoreActionType.Database
 Dim dataFileLocation As [String] = Convert.ToString(dataFilePath + databaseName) & ".mdf"
 Dim logFileLocation As [String] = Convert.ToString(logFilePath + databaseName) & "_Log.ldf"
 db = sqlServer.Databases(databaseName)
 Dim rf As New RelocateFile(databaseName, dataFileLocation)

 sqlRestore.RelocateFiles.Add(New RelocateFile(databaseName, dataFileLocation))
 sqlRestore.RelocateFiles.Add(New RelocateFile(Convert.ToString(databaseName) & "_log", logFileLocation))
 sqlRestore.ReplaceDatabase = True
 sqlRestore.Complete += New ServerMessageEventHandler(sqlRestore_Complete)
 sqlRestore.PercentCompleteNotification = 10
 sqlRestore.PercentComplete += New PercentCompleteEventHandler(sqlRestore_PercentComplete)

 sqlRestore.SqlRestore(sqlServer)

 db = sqlServer.Databases(databaseName)

 db.SetOnline()

 sqlServer.Refresh()
End Sub