codigo de funcionamiento de un formulario, guardar

CODIGO DE FUNCIONAMIENTO DE UN FORMULARIO, GUARDAR – BUSCAR –
ACTUALIZAR - ELIMINAR
Imports System.Data
Imports System.Data.OleDb
Public Class Acciones
Dim conexion As New OleDbConnection
Dim comandos As New OleDbCommand
Dim adaptador As New OleDbDataAdapter
Dim registro As New DataSet
Dim lector As OleDbDataReader
Dim consulta As String
Private Sub btnGuardar_Click(sender As Object, e As EventArgs) Handles
btnSalir.Click
If txtCodigo.Text = "" And txtNombres.Text = "" And txtApellidos.Text = ""
And txtTelefono.Text = "" And txtEmail.Text = "" Then
MsgBox("No debe dejar campos vacios", vbCritical, "Vacios!!!!!")
Else
Try
comandos = New OleDbCommand("INSERT INTO Contactos
(Codigo,Nombres,Apellidos,Telefono,Email)
VALUES(txtCodigo,txtNombres,txtApellidos,txtTelefono,txtEmail)", conexion)
comandos.Parameters.AddWithValue("@Codigo", txtCodigo.Text)
comandos.Parameters.AddWithValue("@Nombres", txtNombres.Text)
comandos.Parameters.AddWithValue("@Apellidos", txtApellidos.Text)
comandos.Parameters.AddWithValue("@Telefono", txtTelefono.Text)
comandos.Parameters.AddWithValue("@Email", txtEmail.Text)
comandos.ExecuteNonQuery()
MsgBox("Los datos han sido guardados", vbInformation, "Exito!!!")
datagridContacto()
limpiar()
Catch ex As Exception
MsgBox("No fue posible guardar los datos", vbCritical, "Error!!!")
End Try
End If
End Sub
Private Sub limpiar()
txtCodigo.Clear()
txtNombres.Clear()
txtApellidos.Clear()
txtTelefono.Clear()
txtEmail.Clear()
txtCodigo.Focus()
End Sub
Private Sub Acciones_FormClosed(sender As Object, e As FormClosedEventArgs)
Handles Me.FormClosed
conexion.Close()
End Sub
Private Sub datagridContacto()
Dim adaptador As New OleDbDataAdapter
Dim registros As New DataSet
Dim consulta As String
consulta = "SELECT * FROM Contactos"
adaptador = New OleDbDataAdapter(consulta, conexion)
registros.Tables.Add("Contactos")
adaptador.Fill(registros.Tables("Contactos"))
dgvcontactos.DataSource = registros.Tables("Contactos")
End Sub
Private Sub Acciones_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
conexion.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data
Source=listado.accdb"
conexion.Open()
datagridContacto()
Catch ex As Exception
MsgBox("Error en la conexion a la BD", vbCritical, "Error de Conexion")
End Try
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles
Button1.Click
conexion.Close()
End
End Sub
Private Sub btnBuscar_Click(sender As Object, e As EventArgs) Handles
btnBuscar.Click
Dim buscar As String
Dim lista As Byte
buscar = "SELECT * FROM Contactos WHERE codigo ='" & txtCodigo.Text & "'"
adaptador = New OleDbDataAdapter(buscar, conexion)
registro = New DataSet
adaptador.Fill(registro, "Contactos")
lista = registro.Tables("Contactos").Rows.Count
If lista <> 0 Then
dgvcontactos.DataSource = registro
dgvcontactos.DataMember = "Contactos"
txtCodigo.Text = registro.Tables("Contactos").Rows(0).Item("Codigo")
txtNombres.Text = registro.Tables("Contactos").Rows(0).Item("Nombres")
txtApellidos.Text =
registro.Tables("Contactos").Rows(0).Item("Apellidos")
txtTelefono.Text = registro.Tables("Contactos").Rows(0).Item("Telefono")
txtEmail.Text = registro.Tables("Contactos").Rows(0).Item("Email")
Else
MsgBox("El dato no existe en la BD", vbCritical, "Error!!!!")
limpiar()
End If
End Sub
Private Sub btnActualizar_Click(sender As Object, e As EventArgs) Handles
btnActualizar.Click
Dim actualizar As String
txtApellidos.Enabled = True
txtNombres.Enabled = True
txtTelefono.Enabled = True
txtEmail.Enabled = True
actualizar = "UPDATE Contactos SET Nombres = '" & txtNombres.Text &
"', Apellidos= '" & txtApellidos.Text & "', Telefono = '" &
txtTelefono.Text & "', Email= '" & txtEmail.Text &
"' WHERE Codigo = '" & txtCodigo.Text & "'"
comandos = New OleDbCommand(actualizar, conexion)
comandos.ExecuteNonQuery()
MsgBox("Datos Actualizados Correctamente", vbInformation, "Correcto!!!")
datagridContacto()
limpiar()
End Sub
Private Sub btnEliminar_Click(sender As Object, e As EventArgs) Handles
btnEliminar.Click
Dim eliminar As String
Dim si As Byte
si = MsgBox("Esta seguro de Eliminar este registro", vbYesNo, "??????")
If vbYes Then
eliminar = "DELETE FROM Contactos Where Codigo = '" & txtCodigo.Text &
"'"
comandos = New OleDbCommand(eliminar, conexion)
comandos.ExecuteNonQuery()
MsgBox("El registro se ha eliminado", vbInformation, "Borrado!!!!!")
datagridContacto()
limpiar()
Else
MsgBox("Cancelo la acción", vbInformation, "Cancelo!!!!")
limpiar()
End If
End Sub
End Class