Koneksi Database Dalam VB .NET [Pertemuan XV:2]

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- Langkah pertama buatlah form lalu design seperti dibawah diatas :

-Lalu masukan code dibawah ini:

Dim cnn As New OleDb.OleDbConnection
    Dim provider As String
    Dim dataFile As String
    Dim connString As String
    Public myConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
    Public dr As OleDb.OleDbDataReader

*pada button close

Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        Me.Close()
    End Sub

*pada button add

Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
        Dim cmd As New OleDb.OleDbCommand
        If Not cnn.State = ConnectionState.Open Then
            'open connection if it is not yet open
            cnn.Open()
        End If

        cmd.Connection = cnn
        'check whether add new or update
        If Me.txtstdID.Tag & "" = "" Then
            'add new 
            'add data to table
            cmd.CommandText = "INSERT INTO student(stdid, stdname, gender, phone, address) " & _
                            " VALUES(" & Me.txtstdID.Text & ",'" & Me.txtStdName.Text & "','" & _
                            Me.cboGender.Text & "','" & Me.txtPhone.Text & "','" & _
                            Me.txtAddress.Text & "')"
            cmd.ExecuteNonQuery()
        Else
            'update data in table
            cmd.CommandText = "UPDATE student " & _
                        " SET stdid=" & Me.txtstdID.Text & _
                        ", stdname='" & Me.txtStdName.Text & "'" & _
                        ", gender='" & Me.cboGender.Text & "'" & _
                        ", phone='" & Me.txtPhone.Text & "'" & _
                        ", address='" & Me.txtAddress.Text & "'" & _
                        " WHERE stdid=" & Me.txtstdID.Tag
            cmd.ExecuteNonQuery()
        End If
        'refresh data in list
        RefreshData()
        'clear form
        Me.btnClear.PerformClick()

        'close connection
        cnn.Close()
    End Sub

*pada button clear

Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        Me.txtstdID.Text = ""
        Me.txtStdName.Text = ""
        Me.txtPhone.Text = ""
        Me.txtAddress.Text = ""
        Me.txtstdID.Tag = ""
        'enable button edit
        Me.btnEdit.Enabled = True
        'set button add to add label
        Me.btnAdd.Text = "Add"
        '
        Me.txtstdID.Focus()
    End Sub

*pada button edit

Private Sub btnEdit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEdit.Click
        'check for the selected item in list
        If Me.dgvData.Rows.Count > 0 Then
            If Me.dgvData.SelectedRows.Count > 0 Then
                Dim intStdID As Integer = Me.dgvData.SelectedRows(0).Cells("id").Value
                'get data from database followed by student id
                'open connection
                If Not cnn.State = ConnectionState.Open Then
                    cnn.Open()
                End If
                'get data into datatable
                Dim da As New OleDb.OleDbDataAdapter("SELECT * FROM student " & _
                                                     " WHERE stdid=" & intStdID, cnn)
                Dim dt As New DataTable
                da.Fill(dt)

                Me.txtstdID.Text = intStdID
                Me.txtStdName.Text = dt.Rows(0).Item("stdname")
                Me.cboGender.Text = dt.Rows(0).Item("gender")
                Me.txtPhone.Text = dt.Rows(0).Item("phone")
                Me.txtAddress.Text = dt.Rows(0).Item("address")
                '
                'hide the id to be edited in TAG of txtstdid in case id is changed
                Me.txtstdID.Tag = intStdID
                'change button add to update
                Me.btnAdd.Text = "Update"
                'disable button edit
                Me.btnEdit.Enabled = False
                'close connection
                cnn.Close()
            End If
        End If
    End Sub

*pada button delete

Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click
        'check for the selected item in list
        If Me.dgvData.Rows.Count > 0 Then
            If Me.dgvData.SelectedRows.Count > 0 Then
                Dim intStdID As Integer = Me.dgvData.SelectedRows(0).Cells("id").Value
                'open connection
                If Not cnn.State = ConnectionState.Open Then
                    cnn.Open()
                End If

                'delete data
                Dim cmd As New OleDb.OleDbCommand
                cmd.Connection = cnn
                cmd.CommandText = "DELETE FROM student WHERE stdid=" & intStdID
                cmd.ExecuteNonQuery()
                'refresh data
                Me.RefreshData()

                'close connection
                cnn.Close()
            End If
        End If
    End Sub

*pada formload

Private Sub frmStudent_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        cnn = New OleDb.OleDbConnection
        cnn.ConnectionString = "Provider=Microsoft.Jet.Oledb.4.0; Data Source=" & Application.StartupPath & "\data.mdb"
        '
        'get data into list
        Me.RefreshData()
    End Sub

Selmat mencoba.