it always say's "Not allowed to change the 'ConnectionString' property. The connection's current state is open." and " Number of query values and destination fields are not the same".

Imports System.Data.OleDb
Public Class Inquiry_Form
    Dim provider As String
    Dim dataFile As String
    Dim connstring As String
    Dim myConnection As OleDbConnection = New OleDbConnection

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        provider = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
        dataFile = "Database3.mdb"
        connstring = provider & dataFile
        myConnection.ConnectionString = connstring
        myConnection.Open()
        Dim str As String
        str = "INSERT INTO Inquiry_Form([Date],[RefNo],[NameP],[Address],[Age],[PhoneNo],[MobileNo],[EmailAd],[ReferralQuestion],[Type_of_Unit],[Date_of_Purchase],[Purpose_of_Purchase],[Monthly_Income],[RName],[RAddress],[RMobileNo],[R2Name],[R2Address],[RMobileNo],[R2Name],[R2Address],[R2MobileNo],[AgentsName]) Values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)"
        Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
        cmd.Parameters.Add(New OleDbParameter("Date", CType(TextBox1.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("RefNo", CType(TextBox2.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("NameP", CType(TextBox3.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Address", CType(TextBox4.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Age", CType(TextBox5.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("PhoneNo", CType(TextBox6.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("MobileNo", CType(TextBox8.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("EmailAd", CType(TextBox7.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("ReferralQuestion", CType(ComboBox1.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Type_of_Unit", CType(ComboBox2.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Date_of_Purchase", CType(ComboBox3.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Purpose_of_Purchase", CType(ComboBox4.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("Monthly_Income", CType(ComboBox5.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("RName", CType(TextBox10.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("RAddress", CType(TextBox11.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("RMobileNo", CType(TextBox15.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("R2Name", CType(TextBox12.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("R2Address", CType(TextBox13.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("R2MobileNo", CType(TextBox14.Text, String)))
        cmd.Parameters.Add(New OleDbParameter("AgentsName", CType(TextBox16.Text, String)))

        Try
            cmd.ExecuteNonQuery()
            cmd.Dispose()
            myConnection.Close()
            TextBox1.Clear()
            TextBox2.Clear()
            TextBox3.Clear()
            TextBox4.Clear()
            TextBox5.Clear()
            TextBox6.Clear()
            TextBox8.Clear()
            TextBox7.Clear()
            TextBox10.Clear()
            TextBox11.Clear()
            TextBox15.Clear()
            TextBox12.Clear()
            TextBox13.Clear()
            TextBox14.Clear()
            TextBox16.Clear()

        Catch ex As Exception
            MsgBox(ex.Message)

        End Try

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Me.Close()
        Menu_Page.Show()
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs)
        Inquiry_FormBindingSource1.AddNew()
    End Sub

    Private Sub Inquiry_Form_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'Database3DataSet.Inquiry_Form' table. You can move, or remove it, as needed.
        Me.Inquiry_FormTableAdapter.Fill(Me.Database3DataSet.Inquiry_Form)

    End Sub


End Class