Asp.net DropDownList, AutoPostBack, and ViewState

Discussion in 'ASP .Net Web Services' started by Corey, Mar 18, 2005.

  1. Corey

    Corey Guest

    I'm trying to finish off do an ASP.NET project where a DropDownList box is
    used to access a Table.
    Once you Make a selection on an item in the DropDownListBox, it updates a
    DataView, and text boxes on the form get updated.

    I'd like to do this without a submit button.

    Shouldn't the DropDownList box PostBack?
    Why does SelectedIndexChanged never get hit?
    Does the answer lie within ViewState?

    Any Info will help...

    Thanks.
    Corey, Mar 18, 2005
    #1
    1. Advertising

  2. Corey

    Cor Ligthert Guest

    Corey,

    Only the button has his autopostback standard set too true. For the other
    controls you have to set that in the properties.

    I hope this helps,

    Cor
    Cor Ligthert, Mar 18, 2005
    #2
    1. Advertising

  3. Corey

    Corey Guest

    Thanks Cor.

    I made the change to the text boxes. Unfortunately there's no change,
    except now when I type in them i get an Javascript Error In Internet
    Explorer which says

    Error: Object expected

    I think I know what is causing this. It's a parameter for a dataset, which
    is missing.

    But what i noticed with the DropDownList is when I changed it, I get a
    javascript error for it too.
    It says

    Line: 1
    Char: 1
    Error: 'WebForm_PostBackOptions' is undefined
    Code: 0

    Does This Help at all? I've searched google and came up with very little.

    Thanks.

    "Cor Ligthert" <> wrote in message
    news:%...
    > Corey,
    >
    > Only the button has his autopostback standard set too true. For the other
    > controls you have to set that in the properties.
    >
    > I hope this helps,
    >
    > Cor
    >
    Corey, Mar 18, 2005
    #3
  4. Corey

    Cor Ligthert Guest

    Corey,

    > I made the change to the text boxes.


    You said dropdownlist, that is the only place you should set the
    autopostback to true in my opinion.

    Cor
    Cor Ligthert, Mar 18, 2005
    #4
  5. Corey

    Corey Guest

    Yeah, I removed it from the text boxes before.

    Any clues on my Javascript error?


    "Cor Ligthert" <> wrote in message
    news:...
    > Corey,
    >
    >> I made the change to the text boxes.

    >
    > You said dropdownlist, that is the only place you should set the
    > autopostback to true in my opinion.
    >
    > Cor
    >
    Corey, Mar 18, 2005
    #5
  6. Corey

    Cor Ligthert Guest

    Corey,

    Can you show by a little piece how you did your code, it is ASPNET and for
    that are three possibilities.

    Cor
    Cor Ligthert, Mar 18, 2005
    #6
  7. Corey

    Corey Guest

    Here's My Code

    <form id="Form1" method="post" runat="server">

    <asp:textbox id=txtFirstName style="Z-INDEX: 101; LEFT: 33px; POSITION:
    absolute; TOP: 56px" runat="server" Width="235px" Height="23px" Text='<%#
    DataBinder.Eval(dvUsers1, "[0].FirstName", "{0}") %>'>

    </asp:textbox><asp:textbox id=txtLastName style="Z-INDEX: 102; LEFT:
    34px; POSITION: absolute; TOP: 99px" runat="server" Width="235px"
    Height="24px" Text='<%# DataBinder.Eval(dvUsers1, "[0].LastName", "{0}")
    %>'></asp:textbox><asp:datagrid id=DataGrid1 style="Z-INDEX: 103; LEFT:
    323px; POSITION: absolute; TOP: -48px" runat="server" Width="386px"
    Height="137px" Visible="False" DataMember="Users" DataKeyField="UserKey"
    DataSource='<%# DataBinder.Eval(DsUsers1, "Tables[Users]") %>'>

    </asp:datagrid><asp:dropdownlist id=DropDownList1 style="Z-INDEX: 104;
    LEFT: 36px; POSITION: absolute; TOP: 20px" runat="server" Width="227px"
    Height="27px" DataMember="Users" DataSource="<%# DsUsers1 %>"
    DataValueField="UserKey" EnableViewState="True" AutoPostBack="True"
    DataTextField="UserID">

    </asp:dropdownlist><asp:datagrid id=DataGrid2 style="Z-INDEX: 105; LEFT:
    34px; POSITION: absolute; TOP: 135px" runat="server"
    DataMember="sp_RulesLookup" DataKeyField="ruledescr" DataSource="<%#
    DsRulesLookup1 %>" AutoGenerateColumns="False">
    <Columns>
    <asp:BoundColumn DataField="ruledescr" SortExpression="ruledescr"
    HeaderText="Rules"></asp:BoundColumn>
    </Columns>
    </asp:datagrid><asp:button id="Button1" style="Z-INDEX: 106; LEFT: 321px;
    POSITION: absolute; TOP: 99px" runat="server" Width="250px" Height="28px"
    Text="Save Changes"></asp:button><asp:button id="Button2" style="Z-INDEX:
    107; LEFT: 324px; POSITION: absolute; TOP: 141px" runat="server"
    Width="253px" Height="28px" Text="Button"></asp:button></form>


    "Cor Ligthert" <> wrote in message
    news:...
    > Corey,
    >
    > Can you show by a little piece how you did your code, it is ASPNET and for
    > that are three possibilities.
    >
    > Cor
    >
    Corey, Mar 18, 2005
    #7
  8. Corey

    Cor Ligthert Guest

    Corey,

    This is the mainly RAD created part of your code.
    I don't know if you have any VBcode so called code behind.

    The problem with this is that I cannot simulate what you did, because it
    depends on your evironment that you draged on your form.

    However there must be as well a part wherin is that event from the
    dropdownlist.

    Cor
    Cor Ligthert, Mar 18, 2005
    #8
  9. Corey

    Corey Guest

    Any time i try to change the DropDownList I get a javascript error which
    says "Error: 'WebForm_PostBackOptions' is undefined"
    How can I restore this?

    VB Code is as follows.


    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
    System.EventArgs) Handles MyBase.Load

    'Put user code to initialize the page here

    If Not IsPostBack Then

    SqlDAUsers.Fill(DsUsers1)

    DropDownList1.DataBind()

    ' DataGrid1.DataBind()

    ' dvUsers1.RowFilter = "Userkey = " & Me.ViewState("DropDownList1") '&
    DsUsers1.Users.UserKeyColumn.ToString()

    txtFirstName.DataBind()

    txtLastName.DataBind()

    SqlDARulesLookup.SelectCommand.Parameters.Item(1).Value =
    DropDownList1.SelectedItem.Value

    SqlDARulesLookup.Fill(DsRulesLookup1)

    DataGrid2.DataBind()

    End If

    ' Response.Write("Selected - " + DropDownList1.SelectedItem.Value)

    ' Response.Write("Uber Select - " & DropDownList1.SelectedIndex)

    End Sub

    Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As
    System.Object, ByVal e As System.EventArgs) Handles
    DropDownList1.SelectedIndexChanged



    ' txtFirstName.Text = DsUsers1.Users.FirstNameColumn.ToString

    ' txtLastName.Text = DsUsers1.Users.LastNameColumn.ToString

    dvUsers1.RowFilter = "Userkey = " & DsUsers1.Users.UserKeyColumn.ToString()

    txtFirstName.DataBind()

    txtLastName.DataBind()

    Response.Write("SelectedIndex!")

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
    System.EventArgs) Handles Button1.Click

    Dim strSQLQuery As String

    strSQLQuery = "UPDATE Users " _

    & "SET FirstName = '" & Replace(txtFirstName.Text, "'", "''") & "', " _

    & "LastName = '" & Replace(txtLastName.Text, "'", "''") & "' " _

    & "WHERE UserKey = " & DropDownList1.SelectedItem.Value & ";"

    'Response.Write(strSQLQuery)

    SqlSaveCommand.CommandText = strSQLQuery

    SqlUsers.Open()

    SqlSaveCommand.ExecuteNonQuery()

    SqlUsers.Close()

    'update datasets?

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As
    System.EventArgs) Handles Button2.Click

    ' Define Crystal Reports variables

    Dim crReportDocument As ReportDocument

    Dim crExportOptions As ExportOptions

    Dim crDiskFileDestinationOptions As DiskFileDestinationOptions

    Dim Fname As String

    ' The following code can be placed directly after the call to

    ' InitializeComponent() in the form's constructor, or inside of

    ' a Button_Click event where the button is used by the client to

    ' get a printable copy of the report.

    crReportDocument = New ReportDocument()

    ' The following line of code loads the sample report "Chart.rpt" that
    installs

    ' with Visual Studio .NET

    crReportDocument.Load("C:\Inetpub\wwwroot\WebApplication3\CrystalReport2.rpt")

    Fname = "C:\inetpub\wwwroot\WebApplication3\" & Session.SessionID.ToString &
    ".pdf"

    crDiskFileDestinationOptions = New DiskFileDestinationOptions()

    crDiskFileDestinationOptions.DiskFileName = Fname

    crExportOptions = crReportDocument.ExportOptions

    With crExportOptions

    ..DestinationOptions = crDiskFileDestinationOptions

    ..ExportDestinationType = ExportDestinationType.DiskFile

    ..ExportFormatType = ExportFormatType.PortableDocFormat

    End With

    crReportDocument.Refresh()

    crReportDocument.Export()

    ' The following code writes the pdf file to the Client's browser.

    Response.ClearContent()

    Response.ClearHeaders()

    Response.ContentType = "application/pdf"

    Response.WriteFile(Fname)

    Response.Flush()

    Response.Close()

    'delete the exported file from disk

    System.IO.File.Delete(Fname)

    End Sub

    End Class


    "Cor Ligthert" <> wrote in message
    news:OEpRyQ$...
    > Corey,
    >
    > This is the mainly RAD created part of your code.
    > I don't know if you have any VBcode so called code behind.
    >
    > The problem with this is that I cannot simulate what you did, because it
    > depends on your evironment that you draged on your form.
    >
    > However there must be as well a part wherin is that event from the
    > dropdownlist.
    >
    > Cor
    >
    Corey, Mar 19, 2005
    #9
  10. Corey

    Corey Guest

    Visual Studio must have put them in.

    "Alvin Bruney [ASP.NET MVP]" <www.lulu.com/owc> wrote in message
    news:%...
    > Why is the Xposted all over the place?
    >
    > --
    > Regards,
    > Alvin Bruney
    > [Shameless Author Plug]
    > The Microsoft Office Web Components Black Book with .NET
    > available at www.lulu.com/owc
    > _________________________
    >
    >
    > "Corey" <> wrote in message
    > news:uju_d.69465$...
    >> I'm trying to finish off do an ASP.NET project where a DropDownList box
    >> is used to access a Table.
    >> Once you Make a selection on an item in the DropDownListBox, it updates a
    >> DataView, and text boxes on the form get updated.
    >>
    >> I'd like to do this without a submit button.
    >>
    >> Shouldn't the DropDownList box PostBack?
    >> Why does SelectedIndexChanged never get hit?
    >> Does the answer lie within ViewState?
    >>
    >> Any Info will help...
    >>
    >> Thanks.
    >>

    >
    >
    Corey, Mar 20, 2005
    #10
  11. Corey

    Cor Ligthert Guest

    Answered in the follow up thread
    Cor Ligthert, Mar 20, 2005
    #11
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Lloyd Sheen
    Replies:
    3
    Views:
    4,742
  2. Corey
    Replies:
    11
    Views:
    6,164
    Cor Ligthert
    Mar 20, 2005
  3. =?Utf-8?B?c3Jp?=
    Replies:
    5
    Views:
    4,548
    =?Utf-8?B?c3Jp?=
    Aug 23, 2005
  4. PJ
    Replies:
    0
    Views:
    545
  5. Corey
    Replies:
    10
    Views:
    692
    Cor Ligthert
    Mar 20, 2005
Loading...

Share This Page