Hello,
I am a beginner in
vb.net. I want to read and write records from a Pervasive db.
Getting data works fine, but when i want to update a record i get an error which i do not understand.
"Object not set to an instance of aan object" System.NullReferenceException
The table doesn't have primary key, only indexes. That's what the data link configurator tells me.
Maybe somebody knows more.
Pervasive v8.6,
vb.net 2002.
Imports Pervasive.Data
Public Class frmUpdatePP
Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'Add any initialization after the InitializeComponent() call
End Sub
'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
Friend WithEvents btnMerkcode As System.Windows.Forms.Button
Friend WithEvents txtArtnr As System.Windows.Forms.TextBox
Friend WithEvents txtZoeknaam As System.Windows.Forms.TextBox
Friend WithEvents btnUpdate As System.Windows.Forms.Button
Friend WithEvents DbRidderart As System.Data.OleDb.OleDbDataAdapter
Friend WithEvents OleDbSelectCommand1 As System.Data.OleDb.OleDbCommand
Friend WithEvents OleDbInsertCommand1 As System.Data.OleDb.OleDbCommand
Friend WithEvents ConnRidderart As System.Data.OleDb.OleDbConnection
Friend WithEvents OleDbUpdateCommand1 As System.Data.OleDb.OleDbCommand
Friend WithEvents DsRidderart As Merkcode.DsRidderart
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
Me.txtArtnr = New System.Windows.Forms.TextBox()
Me.txtZoeknaam = New System.Windows.Forms.TextBox()
Me.btnMerkcode = New System.Windows.Forms.Button()
Me.btnUpdate = New System.Windows.Forms.Button()
Me.DbRidderart = New System.Data.OleDb.OleDbDataAdapter()
Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand()
Me.ConnRidderart = New System.Data.OleDb.OleDbConnection()
Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand()
Me.OleDbUpdateCommand1 = New System.Data.OleDb.OleDbCommand()
Me.DsRidderart = New Merkcode.DsRidderart()
CType(Me.DsRidderart, System.ComponentModel.ISupportInitialize).BeginIni t()
Me.SuspendLayout()
'
'txtArtnr
'
Me.txtArtnr.Location = New System.Drawing.Point(48, 80)
Me.txtArtnr.Name = "txtArtnr"
Me.txtArtnr.Size = New System.Drawing.Size(128, 20)
Me.txtArtnr.TabIndex = 0
Me.txtArtnr.Text = ""
'
'txtZoeknaam
'
Me.txtZoeknaam.Location = New System.Drawing.Point(48, 112)
Me.txtZoeknaam.Name = "txtZoeknaam"
Me.txtZoeknaam.Size = New System.Drawing.Size(128, 20)
Me.txtZoeknaam.TabIndex = 1
Me.txtZoeknaam.Text = ""
'
'btnMerkcode
'
Me.btnMerkcode.Location = New System.Drawing.Point(48, 32)
Me.btnMerkcode.Name = "btnMerkcode"
Me.btnMerkcode.TabIndex = 1
Me.btnMerkcode.Text = "Merkcode"
'
'btnUpdate
'
Me.btnUpdate.Location = New System.Drawing.Point(144, 32)
Me.btnUpdate.Name = "btnUpdate"
Me.btnUpdate.TabIndex = 2
Me.btnUpdate.Text = "Update"
'
'DbRidderart
'
Me.DbRidderart.InsertCommand = Me.OleDbInsertCommand1
Me.DbRidderart.SelectCommand = Me.OleDbSelectCommand1
Me.DbRidderart.TableMappings.AddRange(New System.Data.Common.DataTableMapping() {New System.Data.Common.DataTableMapping("Table", "ARTIKEL", New System.Data.Common.DataColumnMapping() {New System.Data.Common.DataColumnMapping("ARTIKELNUMME R", "ARTIKELNUMMER"), New System.Data.Common.DataColumnMapping("ZOEKNAAM", "ZOEKNAAM")})})
Me.DbRidderart.UpdateCommand = Me.OleDbUpdateCommand1
'
'OleDbInsertCommand1
'
Me.OleDbInsertCommand1.CommandText = "INSERT INTO ARTIKEL(ARTIKELNUMMER, ZOEKNAAM) VALUES (?, ?)"
Me.OleDbInsertCommand1.Connection = Me.ConnRidderart
Me.OleDbInsertCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ARTIKELNUMMER", System.Data.OleDb.OleDbType.VarChar, 17, "ARTIKELNUMMER"))
Me.OleDbInsertCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ZOEKNAAM", System.Data.OleDb.OleDbType.VarChar, 12, "ZOEKNAAM"))
'
'ConnRidderart
'
Me.ConnRidderart.ConnectionString = "Provider=PervasiveOLEDB.8.60;Data Source=Thruster Systems;Location=HRP-DC1;Cache " & _
"Authentication=False;Encrypt Password=False;Mask Password=False;Persist Encrypte" & _
"d=False;Persist Security Info=False;Impersonation Level=Anonymous;Mode=ReadWrite" & _
";Protection Level=None;Auto Translate=False;Port=1583;Pessimistic Read Lock=Fals" & _
"e;CommandOnly=False;DirectOnly=False;LocalTCP=Fal se"
'
'OleDbSelectCommand1
'
Me.OleDbSelectCommand1.CommandText = "SELECT ARTIKELNUMMER, ZOEKNAAM FROM ARTIKEL"
Me.OleDbSelectCommand1.Connection = Me.ConnRidderart
'
'OleDbUpdateCommand1
'
Me.OleDbUpdateCommand1.CommandText = "UPDATE ARTIKEL SET ARTIKELNUMMER =?, ZOEKNAAM =?"
Me.OleDbUpdateCommand1.Connection = Me.ConnRidderart
Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ARTIKELNUMMER", System.Data.OleDb.OleDbType.Char, 17, "ARTIKELNUMMER"))
Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ZOEKNAAM", System.Data.OleDb.OleDbType.Char, 12, "ZOEKNAAM"))
Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ARTIKELNUMMER", System.Data.OleDb.OleDbType.Char, 17, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "ARTIKELNUMMER", System.Data.DataRowVersion.Original, Nothing))
Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("ZOEKNAAM", System.Data.OleDb.OleDbType.Char, 12, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "ZOEKNAAM", System.Data.DataRowVersion.Original, Nothing))
'
'DsRidderart
'
Me.DsRidderart.DataSetName = "DsRidderart"
Me.DsRidderart.Locale = New System.Globalization.CultureInfo("nl-NL")
Me.DsRidderart.Namespace = "http://www.tempuri.org/DsRidderart.xsd"
'
'frmUpdatePP
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.ClientSize = New System.Drawing.Size(292, 266)
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnUpdate, Me.btnMerkcode, Me.txtZoeknaam, Me.txtArtnr})
Me.Name = "frmUpdatePP"
Me.Text = "Update Prijslijst Parts"
CType(Me.DsRidderart, System.ComponentModel.ISupportInitialize).EndInit( )
Me.ResumeLayout(False)
End Sub
#End Region
Dim keyArtikel(0) As String
Private Sub btnMerkcode_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMerkcode.Click
Dim artnr As String = txtArtnr.Text
ConnRidderart.Open()
Dim dt As DataTable = DsRidderart.Tables("ARTIKEL")
dt.PrimaryKey = New DataColumn() {dt.Columns("ARTIKELNUMMER")}
DbRidderart.Fill(DsRidderart)
Dim dr As DataRow
dr = DsRidderart.Tables("ARTIKEL").Rows.Find(artnr)
If Not (dr Is Nothing) Then
txtZoeknaam.Text = dr.Item("ZOEKNAAM")
Else
txtZoeknaam.Text = "geen record"
End If
ConnRidderart.Close()
End Sub
Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click
Dim fndartikel As DataRow
ConnRidderart.Open()
DsRidderart.Clear()
DbRidderart.Fill(DsRidderart)
Dim mycol(0) As Data.DataColumn
Dim dt As DataTable = DsRidderart.Tables("ARTIKEL")
mycol(0) = dt.Columns("ARTIKELNUMMER")
dt.PrimaryKey = mycol
keyArtikel(0) = CStr(txtArtnr.Text)
fndartikel = DsRidderart.Tables("ARTIKEL").Rows.Find(keyArtikel )
If Not (fndartikel Is Nothing) Then
fndartikel.Item("ARTIKELNUMMER") = keyArtikel
fndartikel.Item("ZOEKNAAM") = txtZoeknaam.Text
DbRidderart.Update(dt)
ConnRidderart.Close()
End If
End Sub
End Class
dBforums
>
Problem updating records Pervasive db.
03-18-08, 12:54
Problem updating records Pervasive db.
Linear Mode
