Please Help to fix this Error "object reference not set to instance of an object"

**delion** · 05-13-2007, 5:31 AM

Help Me Please
Why this Message Box appear with this message "object reference not set to instance of an object"
When I type this code

Code:

 
Imports System.Data
Imports System.Data.OleDb
Imports System.Text.RegularExpressions
Public Class frmtoken
Public Enum Data As Integer
id_Mail = 0
sbjMail = 1
End Enum
Private Sub btnTkn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTkn.Click
Dim conDtbsSkrip As OleDbConnection = New OleDbConnection( _
"Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=E:\dtbsSkrip.mdb")
Dim cmdDtbsSkrip As New OleDbCommand()
Dim objDataAdapter As New OleDbDataAdapter
Dim objDataTable As New DataTable
Dim r As New Regex("[^a-zA-Z]")
Try
conDtbsSkrip.Open()
cmdDtbsSkrip.Connection = conDtbsSkrip
'COUNT RECORD sbjMail
cmdDtbsSkrip.CommandType = CommandType.Text
cmdDtbsSkrip.CommandText = _
"SELECT COUNT (*) FROM tblMail WHERE sbjMail"
Dim returnValue As Object
returnValue = cmdDtbsSkrip.ExecuteScalar()
'GET RECORD id_Mail AND sbjMail
cmdDtbsSkrip.CommandType = CommandType.Text
cmdDtbsSkrip.CommandText = _
"SELECT * FROM tblMail"
Dim reader As OleDbDataReader = cmdDtbsSkrip.ExecuteReader()
'RECORD TO ARRAY 1
Dim Arr1(returnValue, 1) As String
Dim x1 As Integer = 0
Dim Tmp1_sbjMail As String = ""
Dim Tmp1_idMail As String = ""
If (reader.HasRows) Then
While reader.Read()
Tmp1_sbjMail = reader("sbjMail")
Tmp1_idMail = reader("id_Mail")
If r.Match(Tmp1_sbjMail).Success Then
Tmp1_sbjMail = r.Replace(Tmp1_sbjMail, " ")
End If
Arr1(x1, Data.id_Mail) = Tmp1_idMail
Arr1(x1, Data.sbjMail) = Tmp1_sbjMail.Trim.ToLower
'lst1.Items.Add("H1:" & Arr1(x1, 0) & "H3:" & Arr1(x1, 1))
x1 = x1 + 1
End While
End If
reader.Dispose()
reader = Nothing
'RECORD TO ARRAY 3
Dim Arr3() As String
Dim x3 As Integer = 0
Dim x33 As Integer = 0
Dim Tmp3_idMail As String = ""
Dim Tmp3_sbjMail As String = ""
Dim Tmp3_kata As String = ""
For x3 = 0 To x1
Tmp3_idMail = Arr1(x3, 0)
Tmp3_sbjMail = Arr1(x3, 1)
Arr3 = Tmp3_sbjMail.Split(" ") 'ERROR START FROM HERE
MsgBox(Arr3(x3))
For x33 = 0 To UBound(Arr3)
Tmp3_kata = Arr3(x33).Trim
If (Tmp3_kata <> "") Then
cmdDtbsSkrip.CommandType = CommandType.Text
cmdDtbsSkrip.CommandText = _
"INSERT INTO tblKata(id_Mail,Kata) values (@id_Mail,@Kata)"
cmdDtbsSkrip.Parameters.AddWithValue("@id_Mail", Tmp3_idMail)
cmdDtbsSkrip.Parameters.AddWithValue("@Kata", Tmp3_kata)
cmdDtbsSkrip.Parameters.AddWithValue("@Status", 1)
cmdDtbsSkrip.ExecuteNonQuery()
cmdDtbsSkrip.Parameters.Clear()
End If
Next x33
Next x3
'VIEW DATA TO FORM
cmdDtbsSkrip.CommandType = CommandType.Text
cmdDtbsSkrip.CommandText = _
"SELECT * FROM tblKata"
objDataAdapter.SelectCommand = cmdDtbsSkrip
objDataAdapter.Fill(objDataTable)
grdToken.DataSource = objDataTable
grdToken.AlternatingRowsDefaultCellStyle.BackColor = Color.WhiteSmoke
grdToken.CellBorderStyle = DataGridViewCellBorderStyle.None
grdToken.SelectionMode = DataGridViewSelectionMode.FullRowSelect
MessageBox.Show("END ....")
Catch OleDbExceptionErr As OleDbException
MessageBox.Show(OleDbExceptionErr.Message, "Access SQL1")
Catch InvalidOperationExceptionErr As InvalidOperationException
MessageBox.Show(InvalidOperationExceptionErr.Message, "Access SQL3")
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
cmdDtbsSkrip.Dispose()
cmdDtbsSkrip = Nothing
conDtbsSkrip.Close()
conDtbsSkrip = Nothing
End Try
End Sub
End Class

Help me To fix it
Thanks

**cjard** · 05-13-2007, 5:50 AM

Um.. please read http://www.vbdotnetforums.com/misc.php?do=bbcode - the section about [CODE] tags.
Also googling for "object reference not set" will give you hundreds of hits; its one of the most basic errors there is

**the_atom** · 05-15-2007, 1:22 AM

Most of the time, this kind of error is being thrown if you refer to a non-object. Objects are created with the keyword New. VS.NET has a very good tool of pointing to that line of error if an error is thrown. But as i can see in your code in this line:

While reader.Read()
Tmp1_sbjMail = reader("sbjMail")
Tmp1_idMail = reader("id_Mail")

You didn't specify a method for the OleDbDataReader. Try this:

While reader.Read()
Tmp1_sbjMail = reader.item("sbjMail")
Tmp1_idMail = reader.item("id_Mail")

Which reader.item returns an object the result is if you didn't iclude the item method the Tmp1_sbjMail and Tmp1_idMail will refer to a non-object.

Hope this helps