Keskustelu: Ohjelmointikysymykset: VB.NET: vb2010 - Tietokannat - tarkista löytyykö arvo

 'Huom! Esimerkki on väännetty SharpDevelop 4.2:lla
Imports System
Imports System.Data
Imports System.Data.OleDb

Public Partial Class MainForm

	Dim conn As OleDbConnection = Nothing
	Dim KalustoDataSet As DataSet = Nothing
	Dim KalustoAdapter As OleDbDataAdapter = Nothing
	Dim connstr As String = String.Empty

	Public Sub New()
		Me.InitializeComponent()
	End Sub

	Sub MainFormLoad(sender As Object, e As EventArgs)

		conn = New OleDbConnection

		Dim dbPath As String = Environment.GetFolderPath( _
		Environment.SpecialFolder.MyDocuments) 'esim.
		dbPath += "\Kalusto.accdb"
		connstr = "Provider=Microsoft.ACE.OLEDB.12.0;" + _
		"Data Source="+ dbPath + ";Persist Security Info=False;"
		Try
			conn.ConnectionString = connstr
			conn.Open
		Catch ex As Exception
			MsgBox(ex.Message)
		End Try



	End Sub

	Sub Button1Click(sender As Object, e As EventArgs)

		If textBox1.Text = String.Empty Then
			textBox1.Focus
		End If

		If conn.State = ConnectionState.Open Then

			Dim query As String = "SELECT * FROM Autot WHERE REK_NRO ='" + textBox1.Text + "'"
			KalustoAdapter = New OleDbDataAdapter(query, connstr)
			KalustoDataSet = New DataSet
			KalustoAdapter.Fill(KalustoDataSet, "Autot")

			If KalustoDataSet.Tables("Autot").Rows.Count > 0 Then
				MsgBox("LÖYTYI")
			End If

			KalustoAdapter = Nothing
			KalustoDataSet = Nothing

		End If

	End Sub


	Sub MainFormFormClosing(sender As Object, e As FormClosingEventArgs)

		If conn.State = ConnectionState.Open Then
			conn.Close
		End If

		conn = Nothing

	End Sub

End Class