Object reference not set to an instance of an object

Last post 07-19-2012 15:01 by subandi08. 3 replies.

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07-18-2011 8:35

ricohsanusi
Joined on 07-18-2011
Posts 2
Points 25

Object reference not set to an instance of an object

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Dear, all

Mohon bantuan. saya sedang buat aplikasi. aplikasi ini akan meng-insert record baru jika sebelumnya tidak ada, dan akan mengupdate record jika sebelumnya sudah ada.

Berikut kodenya :

Try
                        OleDbConnection1.Open()

                        'set up an SQL select
                        Dim commands As String
                        commands = "SELECT * FROM tblLds WHERE fltno='" & "GA" & fltno & "' AND depsta='" & fromtomatch11.ToString & "' AND arrsta='" & fromtomatch3.ToString.Trim & "' AND datelds='" & depdate2 & "'"
                        OleDbDataAdapter1.SelectCommand.CommandText = commands
                        ' do the select
                        OleDbDataAdapter1.SelectCommand.ExecuteNonQuery()

                        Dim j As Integer = OleDbDataAdapter1.SelectCommand.ExecuteNonQuery
                        If (j = 0) Then
                            'set up an SQL insert
                            Dim commandi As String
                            commandi = "INSERT INTO tblLds VALUES ('" & weightmatch.ToString.Trim & "','" & "GA" & fltno & "','" & ednomatch1.ToString & "','" & bacasign4 & "','" & signmatch5.ToString.Trim & "','" & fromtomatch11.ToString & "','" & fromtomatch3.ToString.Trim & "','" & "PK" & acmatch1.ToString & "','" & vermatch2.ToString & "','" & bacacock & "','" & bacacab1 & "','" & depdate2 & "')"
                            OleDbDataAdapter1.InsertCommand.CommandText = commandi
                            ' do the insert
                            OleDbDataAdapter1.InsertCommand.ExecuteNonQuery()

Else

                            'set up an SQL update
                            Dim commandu As String
                            commandu = "UPDATE tblLds SET edno='" & ednomatch1.ToString & "' WHERE fltno='" & "GA" & fltno & "' AND depsta='" & fromtomatch11.ToString & "' AND arrsta='" & fromtomatch3.ToString.Trim & "' AND datelds='" & depdate2 & "'"
                            OleDbDataAdapter1.UpdateCommand.CommandText = commandu
                            ' do the update
                            OleDbDataAdapter1.UpdateCommand.ExecuteNonQuery()
                        End If
                    Catch exceptionObject As Exception
                        MessageBox.Show(exceptionObject.Message)
                    Finally
                    OleDbConnection1.Close()
                End Try

Untuk proses insert record baru sukses. tapi ketika untuk mengupdate record muncul error "object reference not set to an instance of an object" saat mengeksekusi "OleDbDataAdapter1.UpdateCommand.CommandText = commandu"

Mohon bantuan. Terimakasih :)

Ttd,

Ricoh Sanusi

Post Points: 20

07-20-2011 11:38 In reply to

ricohsanusi
Joined on 07-18-2011
Posts 2
Points 25

Re: Object reference not set to an instance of an object

Reply Contact

ok, case closed afteri changed the updating code into :

                            'set up an SQL update
                            Dim OleDbUpdateCommand As System.Data.OleDb.OleDbCommand
                            OleDbUpdateCommand = New System.Data.OleDb.OleDbCommand
                            OleDbUpdateCommand.Connection = OleDbConnection1
                            OleDbUpdateCommand.CommandText = "UPDATE tblLds SET edno='" & ednomatch1.ToString & "' WHERE fltno='" & "GA" & fltno & "' AND depsta='" & fromtomatch11.ToString & "' AND arrsta='" & fromtomatch3.ToString.Trim & "' AND datelds='" & depdate2 & "'"
                            OleDbDataAdapter1.UpdateCommand = OleDbUpdateCommand
                            OleDbDataAdapter1.UpdateCommand.ExecuteNonQuery()

Ricoh Sanusi Smile

Post Points: 5

07-30-2011 17:35 In reply to

isman
Joined on 06-07-2011
Bogor
Posts 21
Points 150

Re: Object reference not set to an instance of an object

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kayaknya OleDbDataAdapter1 harus diinstansiasi lagi setelah mengeksekusi selectcommand

Filed under: VB.NET

Post Points: 20

07-19-2012 15:01 In reply to

subandi08
Joined on 06-27-2009
Posts 1
Points 5

Re: Object reference not set to an instance of an object

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saya install dotnetnuke 4.5 di windows server 2003

saya buat virtual directory untuk dotnetnukenya kemudian execute permission script only

tapi setelah saya jalankan errornya sbb:

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the 
current web request. Information regarding the origin and location of the 
exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
   DotNetNuke.HttpModules.UrlRewriteModule.RewriteUrl(HttpApplication app) +318
   DotNetNuke.HttpModules.UrlRewriteModule.OnBeginRequest(Object s, EventArgs e) +506
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +68
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

mungkin ada yang tahu

subandi

Post Points: 5

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