dropdownlist in asp.net

miranda · 01-05-2005, 05:31 AM

My drop down list works but no matter what the user selects as an option it always returns the ist line after the form posts. Anyone know what the problem is?

here is the code

Code:

Sub Page_Load(sender as Object, e as EventArgs) 
    Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; "& _ 
        "Data Source=C:\Documents and Settings\Miranda\My Documents\Dobyns\mydb.mdb" 
    Dim dbConnection As New OleDbConnection(connectionString) 
    dbConnection.Open() 
    Dim queryString As String = "SELECT stateCode, state FROM usaStates ORDER by state" 
    Dim dbCommand As New OleDbCommand(queryString,dbConnection) 
    Dim objDR as OleDbDataReader = dbCommand.ExecuteReader() 
    'Databind the DataReader to the listbox Web control 
    lstStates.DataSource = objDR 
    lstStates.DataBind() 

    'Add a new listitem to the beginning of the listitem collection 
    lstStates.Items.Insert(0, new ListItem("-- Choose a State --")) 

    dbConnection.Close() 

End Sub 

Sub Button1_Click(sender As Object, e As EventArgs)
        If Page.IsValid Then
            Dim customerDS As New DataSet

            customerDS = CheckForRecord(company.Text,address1.Text,City.Text,lstStates.SelectedItem.Value)

            If customerDS.Tables(0).Rows.Count = 1 Then
                msgLabel.Text = "Customer Exists"
            ElseIf NewCustomer(company.Text, address1.Text, address2.Text, city.Text, lstStates.SelectedItem.Value, zip.Text, phone.Text, TollFree.Text, fax.Text, contactName.Text, extension.Text, email.text, isShipper.Checked, isConsignee.Checked, isCarrier.Checked, isThirdParty.Checked, comments.Text) > 0 Then
                msgLabel.Text = "Success"
                DataGrid1.DataSource = GetCustomers()
                DataGrid1.DataBind()
                'ResetAllFields()
            End If

        End If
End Sub

'add new customer
    Function NewCustomer( _
                ByVal company As String,  _
                ByVal address1 As String,  _
                ByVal address2 As String,  _
                ByVal city As String,  _
                ByVal state As String,  _
                ByVal zip As String,  _
                ByVal contactName As String,  _
                ByVal phone As String,  _
                ByVal tollfree As String,  _
                ByVal extension As String,  _
                ByVal fax As String,  _
                ByVal email As String, _
                ByVal isShipper As Boolean,  _
                ByVal isConsignee As Boolean,  _
                ByVal isThirdParty As Boolean,  _
                ByVal isCarrier As Boolean,  _
                ByVal comments As String) As Integer
        Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; "& _
            "Data Source=C:\Documents and Settings\Miranda\My Documents\Dobyns\mcdb.mdb"
        Dim dbConnection As System.Data.IDbConnection = New System.Data.OleDb.OleDbConnection(connectionString)

        Dim queryString As String = "INSERT INTO customers (company,address1,address2,city,state,zip,contactName,"& _
            "phone,tollfree,extension,fax,email,isShipper,isConsignee,isThirdParty,isCarrier,comments) "& _
            "VALUES (@company, @address1, @address2, @city, @state, @zip, @contactName, @phone, "& _
            "@tollfree, @extension, @fax, @email, @isShipper, @isConsignee, @isThirdParty, @isCarrier, @comments)"
        Dim dbCommand As System.Data.IDbCommand = New System.Data.OleDb.OleDbCommand
        dbCommand.CommandText = queryString
        dbCommand.Connection = dbConnection

        Dim dbParam_company As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_company.ParameterName = "@company"
        dbParam_company.Value = company
        dbParam_company.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_company)
        Dim dbParam_address1 As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_address1.ParameterName = "@address1"
        dbParam_address1.Value = address1
        dbParam_address1.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_address1)
        Dim dbParam_address2 As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_address2.ParameterName = "@address2"
        dbParam_address2.Value = address2
        dbParam_address2.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_address2)
        Dim dbParam_city As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_city.ParameterName = "@city"
        dbParam_city.Value = city
        dbParam_city.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_city)
        Dim dbParam_state As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_state.ParameterName = "@state"
        dbParam_state.Value = state
        dbParam_state.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_state)
        Dim dbParam_zip As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_zip.ParameterName = "@zip"
        dbParam_zip.Value = zip
        dbParam_zip.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_zip)
        Dim dbParam_contactName As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_contactName.ParameterName = "@contactName"
        dbParam_contactName.Value = contactName
        dbParam_contactName.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_contactName)
        Dim dbParam_phone As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_phone.ParameterName = "@phone"
        dbParam_phone.Value = phone
        dbParam_phone.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_phone)
        Dim dbParam_tollfree As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_tollfree.ParameterName = "@tollfree"
        dbParam_tollfree.Value = tollfree
        dbParam_tollfree.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_tollfree)
        Dim dbParam_extension As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_extension.ParameterName = "@extension"
        dbParam_extension.Value = extension
        dbParam_extension.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_extension)
        Dim dbParam_fax As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_fax.ParameterName = "@fax"
        dbParam_fax.Value = fax
        dbParam_fax.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_fax)
        Dim dbParam_email As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_email.ParameterName = "@email"
        dbParam_email.Value = email
        dbParam_email.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_email)
        Dim dbParam_isShipper As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_isShipper.ParameterName = "@isShipper"
        dbParam_isShipper.Value = isShipper
        dbParam_isShipper.DbType = System.Data.DbType.Boolean
        dbCommand.Parameters.Add(dbParam_isShipper)
        Dim dbParam_isConsignee As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_isConsignee.ParameterName = "@isConsignee"
        dbParam_isConsignee.Value = isConsignee
        dbParam_isConsignee.DbType = System.Data.DbType.Boolean
        dbCommand.Parameters.Add(dbParam_isConsignee)
        Dim dbParam_isThirdParty As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_isThirdParty.ParameterName = "@isThirdParty"
        dbParam_isThirdParty.Value = isThirdParty
        dbParam_isThirdParty.DbType = System.Data.DbType.Boolean
        dbCommand.Parameters.Add(dbParam_isThirdParty)
        Dim dbParam_isCarrier As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_isCarrier.ParameterName = "@isCarrier"
        dbParam_isCarrier.Value = isCarrier
        dbParam_isCarrier.DbType = System.Data.DbType.Boolean
        dbCommand.Parameters.Add(dbParam_isCarrier)
        Dim dbParam_comments As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_comments.ParameterName = "@comments"
        dbParam_comments.Value = comments
        dbParam_comments.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_comments)

        Dim rowsAffected As Integer = 0
        dbConnection.Open
        Try
            rowsAffected = dbCommand.ExecuteNonQuery
        Catch
            msgLabel.Text = lstStates.SelectedItem.Value
            'msgLabel.Text = "Database Error"
            msgLabel.Visible = true
        Finally
            dbConnection.Close
        End Try

        Return rowsAffected
    End Function

and here is the tag itself

Code:

<asp:DropDownList id="lstStates" runat="server" DataValueField="stateCode" DataTextField="state" Rows="1"></asp:DropDownList>

can anyone tell me why it always returns -- Choose a State -- ??

Roelf · 01-05-2005, 06:43 AM

with the postback you rebuild the entire dropdownlist. You should check in your Page_Load handler for the Page.IsPostBack member, to see if it you should rebuild the dropdown. If not, handle the click event

So your Page_load should look like this:

Code:

Sub Page_Load(sender as Object, e as EventArgs) 
  IF Not Page.IsPostBack Then
    Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; "& _ 
        "Data Source=C:\Documents and Settings\Miranda\My Documents\Dobyns\mydb.mdb" 
    Dim dbConnection As New OleDbConnection(connectionString) 
    dbConnection.Open() 
    Dim queryString As String = "SELECT stateCode, state FROM usaStates ORDER by state" 
    Dim dbCommand As New OleDbCommand(queryString,dbConnection) 
    Dim objDR as OleDbDataReader = dbCommand.ExecuteReader() 
    'Databind the DataReader to the listbox Web control 
    lstStates.DataSource = objDR 
    lstStates.DataBind() 

    'Add a new listitem to the beginning of the listitem collection 
    lstStates.Items.Insert(0, new ListItem("-- Choose a State --")) 

    dbConnection.Close() 
  Else
    'do other initialisation stuff
  End If
End Sub

miranda · 01-05-2005, 05:44 PM

I found out from another board that was what I was missing. All of the search results I found on that and not one of them mentioned to check for Page.IsPostBack.