problem in oledb.connection

[karthikeyan]

hi
at present iam working in oracle forms
in my form there is one text bix,4 command buttons,and one picture box.the name of the buttons are browse image,read image,save image,usedatareader.i am using acess as a database,if i clilck browse image using this i can get an image and if i click save image it has to be save in my database,if i click read image the image has to be shown in the picture box.
in my acess table the folllowing feilds are there
userid autonumber
username text
userphoto oleobject
the followind code i did

Imports System.Data.OleDb
Imports System.IO
 
Public Class Form1
    Inherits System.Windows.Forms.Form
    Private curImage As Image = Nothing
    Private curFileName As String = Nothing
    Private connectionString As String = _
      "Provider=Microsoft.Jet.OLEDB.4.0; " & _
      "Data Source=C:\AppliedAdoNet.mdb"
    Private savedImageName As String _
      = "C:\\ImageFromDb.BMP"
 
 
#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 TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents Button3 As System.Windows.Forms.Button
    Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
    Friend WithEvents Button4 As System.Windows.Forms.Button
    Friend WithEvents DB2DataAdapter1 As DDTek.DB2.DB2DataAdapter
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.TextBox1 = New System.Windows.Forms.TextBox
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Button3 = New System.Windows.Forms.Button
        Me.PictureBox1 = New System.Windows.Forms.PictureBox
        Me.Button4 = New System.Windows.Forms.Button
        Me.DB2DataAdapter1 = New DDTek.DB2.DB2DataAdapter
        Me.SuspendLayout()
        '
        'TextBox1
        '
        Me.TextBox1.Location = New System.Drawing.Point(40, 48)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.Size = New System.Drawing.Size(168, 20)
        Me.TextBox1.TabIndex = 0
        Me.TextBox1.Text = "TextBox1"
        '
        'Button1
        '
        Me.Button1.Location = New System.Drawing.Point(264, 40)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(152, 40)
        Me.Button1.TabIndex = 1
        Me.Button1.Text = "browse image"
        '
        'Button2
        '
        Me.Button2.Location = New System.Drawing.Point(40, 136)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(136, 40)
        Me.Button2.TabIndex = 2
        Me.Button2.Text = "save image"
        '
        'Button3
        '
        Me.Button3.Location = New System.Drawing.Point(256, 136)
        Me.Button3.Name = "Button3"
        Me.Button3.Size = New System.Drawing.Size(152, 40)
        Me.Button3.TabIndex = 3
        Me.Button3.Text = "read image"
        '
        'PictureBox1
        '
        Me.PictureBox1.Location = New System.Drawing.Point(8, 184)
        Me.PictureBox1.Name = "PictureBox1"
        Me.PictureBox1.Size = New System.Drawing.Size(744, 352)
        Me.PictureBox1.TabIndex = 4
        Me.PictureBox1.TabStop = False
        '
        'Button4
        '
        Me.Button4.Location = New System.Drawing.Point(472, 48)
        Me.Button4.Name = "Button4"
        Me.Button4.Size = New System.Drawing.Size(176, 32)
        Me.Button4.TabIndex = 5
        Me.Button4.Text = "usedatareader"
        '
        'DB2DataAdapter1
        '
        Me.DB2DataAdapter1.DeleteCommand = Nothing
        Me.DB2DataAdapter1.InsertCommand = Nothing
        Me.DB2DataAdapter1.SelectCommand = Nothing
        Me.DB2DataAdapter1.UpdateCommand = Nothing
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(760, 534)
        Me.Controls.Add(Me.Button4)
        Me.Controls.Add(Me.PictureBox1)
        Me.Controls.Add(Me.Button3)
        Me.Controls.Add(Me.Button2)
        Me.Controls.Add(Me.Button1)
        Me.Controls.Add(Me.TextBox1)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
 
    End Sub
 
#End Region
 
 
    Private Sub BrowseBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim openDlg As OpenFileDialog = New OpenFileDialog
        openDlg.Filter = "All Bitmap files|*.bmp"
        Dim filter As String = openDlg.Filter
        openDlg.Title = "Open a Bitmap File"
        If (openDlg.ShowDialog() = DialogResult.OK) Then
            curFileName = openDlg.FileName
            TextBox1.Text = curFileName
        End If
    End Sub
 
    Private Sub SaveImageBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
 
        If TextBox1.Text Is String.Empty Then
            MessageBox.Show("Browse a bitmap")
            Return
        End If
        ' Read a bitmap contents in a stream
        Dim fs As FileStream = New FileStream(curFileName, FileMode.OpenOrCreate, FileAccess.Read)
 
        Dim rawData() As Byte = New Byte(fs.Length) {}
        fs.Read(rawData, 0, System.Convert.ToInt32(fs.Length))
        fs.Close()
        ' Construct a SQL string and a connection object
        Dim sql As String = "SELECT * FROM user"
        Dim conn As OleDbConnection = New OleDbConnection
        conn.ConnectionString = connectionString
        ' Open connection
        If conn.State <> ConnectionState.Open Then
            conn.Open()
        End If
        ' Create a data adapter and data set
        Dim adapter As OleDbDataAdapter = New OleDbDataAdapter(sql, conn)
        Dim cmdBuilder As OleDbCommandBuilder = New OleDbCommandBuilder(adapter)
        Dim ds As DataSet = New DataSet("user")
        adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey
 
        ' Fill data adapter
        adapter.Fill(ds, "user")
 
        Dim userDes As String = "Mahesh Chand is a founder of C# Corner "
        userDes += "Author: 1. A Programmer's Guide to ADO.NET;"
        userDes += ", 2. Applied ADO.NET. "
 
        ' Create a new row
        Dim row As DataRow = ds.Tables("user").NewRow()
        row("userid") = "100"
        row("UserName") = "karthikeyan"
        row("UserPhoto") = rawData
        ' Add row to the collection
        ds.Tables("user").Rows.Add(row)
        ' Save changes to the database
        adapter.Update(ds, "user")
        ' Clean up connection
        If conn Is Nothing Then
            If conn.State = ConnectionState.Open Then
                conn.Close()
            End If
            ' Dispose connection
            conn.Dispose()
        End If
        MessageBox.Show("Image Saved")
    End Sub
 
 
 
    Private Sub button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
 
        ' Construct a SQL string and a connection object
        Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; " & "Data Source=C:\AppliedAdoNet.mdb"
        Dim sql As String = "SELECT userPhoto FROM user"
        Dim conn As OleDbConnection = New OleDbConnection
        conn.ConnectionString = connectionString
        ' Open connection
        'If conn.State <> ConnectionState.Open Then
        conn.Open()
        'End If
 
        Dim cmd As OleDbCommand = New OleDbCommand(sql, conn)
        Dim fs As FileStream
        Dim bw As BinaryWriter
        Dim bufferSize As Integer = 300000
        Dim outbyte(300000 - 1) As Byte
        Dim retval As Long
        Dim startIndex As Long = 0
        Dim pub_id As String = ""
        Dim reader As OleDbDataReader = _
            cmd.ExecuteReader(CommandBehavior.SequentialAccess)
        ' Read first record
        reader.Read()
        fs = New FileStream(savedImageName, FileMode.OpenOrCreate, FileAccess.Write)
        bw = New BinaryWriter(fs)
        startIndex = 0
        retval = reader.GetBytes(0, 0, outbyte, 0, bufferSize)
        bw.Write(outbyte)
        bw.Flush()
        ' Close the output file.
        bw.Close()
        fs.Close()
        reader.Close()
        ' Display image 
        curImage = Image.FromFile(savedImageName)
        PictureBox1.Image = curImage
        PictureBox1.Invalidate()
        ' Clean up connection
        If conn.State = ConnectionState.Open Then
            conn.Close()
            ' Dispose connection
            conn.Dispose()
        End If
 
 
    End Sub
End Class

after compiling i got succeed,but if i browse the image and try to save that using the button i am getting the following error.

"An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll"
also problem comming in "conn.open"

so what to do.

[taxes]

Hi,

Also, you are being far too vague for anyone to help. I have not looked at your other threads but would try to make some helpful comments:

1. If you feel your last post is being ignored or missed, just add another brief post to it saying something like "Anyone please?" or simply "Bump"

2. Problems with database connections are usually errors in the connection string (that assumes you have correctly created the instance). Check your path - make sure the database is where you think it is - and any passwords. But if you have got as far as your first error then your conn must be working.

3. "An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in system.data.dll" often indicates a problem with field naming or data type conflict. e.g.

Field Naming.

a) VB.NET will only allow field names to contain alpha-numeric characters or the underscore ( _ ), even though Access will permit other characters such as spaces, brackets, some arithmetic signs, etc. Always begin your field names with an alphabetic character or an underscore - not a number

b) Make sure your field names are not reserved words, in either VB.NET or Access (Assuming your database is Access). Either use a prefix e.g. sName instead of Name or place the reserved word in square brackets [ ] in your query.

Data Type Conflict

Make sure the data from VB.NEt is the same type as the Database field.


Always use a Try....catch block around database code because it will give you the exact cause of the error.

If you don't post your code AND indicate the line giving rise to the error, that's the best I can do.

[jmcilhinney]

...but would try to make some helpful comments

Is that a dig at me or have I just got a guilty conscience?

[taxes]

Is that a dig at me or have I just got a guilty conscience?

Hi,

NO WAY I have great respect for your input. Also, I've just looked at his other threads and understand your comments. You ARE trying to be helpful to him and guide him for future posts.

No, my reference to trying to be helpful was solely related to my lack of knowledge added to his lack of information.

Having looked at his posts, I see he is using Oracle ( about which I know nothing) but I thought Microsoft Jet.4 .... was only used for Access databases.

Keep posting please.

[Asgorath]

You connection string seems to be incomplete http://www.connectionstrings.com/.
Put a try catch block to get a precise error message.

Regards
Jorge

[gigemboy]

This is the only post I am going to give you, since you don't seem to be following directions for the multiple threads. For 1 thing you need a SELECT command in order to select your values you need from the database, not an INSERT command, that's just basic SQL knowledge (although that INSERT statement might be for when you add records)

As for the rest, there is a help topic you should look up, it is titled "Accessing Data With ADO.NET" in the Help file, or MSDN would have it if you did not install the Help. It has plenty of info there WITH EXAMPLES... you need to start researching the material you are working on instead of trying to throw together items from different sources without knowing what they do...

[mar_zim]

Ooohh. Please don't create a new thread for the continuation of our discussion just click the post reply button and not the new thread button.

Ok I try to figure out your code.

Imports System.Data.OleDb
 
Public Class Form1
Inherits System.Windows.Forms.Form
 
'Declare your connection globally
Dim cn as New OleDbConnection(strConn)
 
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim cmd As New OleDbCommand("INSERT INTO users (userid, password)VALUES('" & txtuserid.Text & "','" & txtpassword.Text & "')", cn)
cn.Open()
cmd.ExecuteNonQuery()
cn.Close()
 
End Sub
End Class

Btw what is Repeater1? Is it a datagrid?