AJAX and IsPostBack

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  • BM
    #1

    AJAX and IsPostBack

    I have a question that seems like it should have a simple answer, but
    I can't seem to find it by searching...

    Anyway, I'm trying to capture the IsPostBack event when I select an
    item within an UpdatePanel. I don't want items running during
    postback (list, grid population, etc) events - pretty standard: If
    IsPostBack Then Exit Sub

    But, since AJAX doesn't technically postback (?), the IsPostBack is
    coming back false...

    So, how can I capture the Async postback done by AJAX? Is there any
    IsAsyncPostBack keyword and what library is it in?

    Page load process:
    1. Load drop down menus
    2. Load data grids

    "Postback process"
    1. Select datagrid row
    2. Populate several fields below with further information

    When I select the datagrid row, IsPostBack remains false. I've tried
    splitting into multiple update panels but now they are all in a
    singular panel.

    TIA for the help!
    Tags: None
    • George Ter-Saakov
      #2
      Re: AJAX and IsPostBack

      AJAX call runs as a POST back. Just test it...

      George.
      "BM" <moore.brent@gm ail.comwrote in message
      news:a91154c5-39c2-4a5f-9c2a-4a586ef9b1cd@u6 9g2000hse.googl egroups.com...
      >I have a question that seems like it should have a simple answer, but
      I can't seem to find it by searching...
      >
      Anyway, I'm trying to capture the IsPostBack event when I select an
      item within an UpdatePanel. I don't want items running during
      postback (list, grid population, etc) events - pretty standard: If
      IsPostBack Then Exit Sub
      >
      But, since AJAX doesn't technically postback (?), the IsPostBack is
      coming back false...
      >
      So, how can I capture the Async postback done by AJAX? Is there any
      IsAsyncPostBack keyword and what library is it in?
      >
      Page load process:
      1. Load drop down menus
      2. Load data grids
      >
      "Postback process"
      1. Select datagrid row
      2. Populate several fields below with further information
      >
      When I select the datagrid row, IsPostBack remains false. I've tried
      splitting into multiple update panels but now they are all in a
      singular panel.
      >
      TIA for the help!

        Comment

        • =?Utf-8?B?YnJ1Y2UgYmFya2Vy?=
          #3
          RE: AJAX and IsPostBack

          an update panel async callback does set IsPostback true (as this is a just a
          test for __Viewstate and the callback sends all form fields). you can also
          check the scriptmanger.Is InAsyncPostBack

          -- bruce (sqlwork.com)


          "BM" wrote:
          I have a question that seems like it should have a simple answer, but
          I can't seem to find it by searching...
          >
          Anyway, I'm trying to capture the IsPostBack event when I select an
          item within an UpdatePanel. I don't want items running during
          postback (list, grid population, etc) events - pretty standard: If
          IsPostBack Then Exit Sub
          >
          But, since AJAX doesn't technically postback (?), the IsPostBack is
          coming back false...
          >
          So, how can I capture the Async postback done by AJAX? Is there any
          IsAsyncPostBack keyword and what library is it in?
          >
          Page load process:
          1. Load drop down menus
          2. Load data grids
          >
          "Postback process"
          1. Select datagrid row
          2. Populate several fields below with further information
          >
          When I select the datagrid row, IsPostBack remains false. I've tried
          splitting into multiple update panels but now they are all in a
          singular panel.
          >
          TIA for the help!
          >

            Comment

            • BM
              #4
              Re: AJAX and IsPostBack

              On Apr 7, 1:01 pm, "George Ter-Saakov" <gt-...@cardone.com wrote:
              AJAX call runs as a POST back. Just test it...
              >
              George."BM" <moore.br...@gm ail.comwrote in message
              >
              news:a91154c5-39c2-4a5f-9c2a-4a586ef9b1cd@u6 9g2000hse.googl egroups.com...
              >
              I have a question that seems like it should have a simple answer, but
              I can't seem to find it by searching...
              >
              Anyway, I'm trying to capture the IsPostBack event when I select an
              item within an UpdatePanel. I don't want items running during
              postback (list, grid population, etc) events - pretty standard: If
              IsPostBack Then Exit Sub
              >
              But, since AJAX doesn't technically postback (?), the IsPostBack is
              coming back false...
              >
              So, how can I capture the Async postback done by AJAX? Is there any
              IsAsyncPostBack keyword and what library is it in?
              >
              Page load process:
              1. Load drop down menus
              2. Load data grids
              >
              "Postback process"
              1. Select datagrid row
              2. Populate several fields below with further information
              >
              When I select the datagrid row, IsPostBack remains false. I've tried
              splitting into multiple update panels but now they are all in a
              singular panel.
              >
              TIA for the help!
              Thanks - I did test it and I suppose I wasn't 100% clear. It _does_
              run a PostBack but it runs through the page initialization once first
              with IsPostBack=Fals e and then it runs it again with IsPostBack=True

              Page_Init() [originally under PreRender]
              1 If IsPostBack Then
              2 Exit Sub
              3 End If
              4
              5 loadDropDowns()
              6 loadIncompleteG rid()

              Obviously when I first load the page, lines 5 and 6 run.
              When I click on the DataGrid, it runs lines 5 and 6 and then runs
              through again with the break at line 2

              Maybe then there's something more wrong with my pages...

                Comment

                • Mark Fitzpatrick
                  #5
                  Re: AJAX and IsPostBack

                  You may want to play with the timing. Try moving your calls to the
                  subroutines into an event that's further up the heirarchy such as the OnLoad
                  event. You should find that the behavior changes at some point as you get
                  further into the page lifecycle.

                  Hope this helps,
                  Mark Fitzpatrick
                  Microsoft MVP - Expression

                  "BM" <moore.brent@gm ail.comwrote in message
                  news:d04a2cb1-0b23-4f11-aee4-2aa62de11a7c@a1 g2000hsb.google groups.com...
                  On Apr 7, 1:01 pm, "George Ter-Saakov" <gt-...@cardone.com wrote:
                  >AJAX call runs as a POST back. Just test it...
                  >>
                  >George."BM" <moore.br...@gm ail.comwrote in message
                  >>
                  >news:a91154c 5-39c2-4a5f-9c2a-4a586ef9b1cd@u6 9g2000hse.googl egroups.com...
                  >>
                  >I have a question that seems like it should have a simple answer, but
                  I can't seem to find it by searching...
                  >>
                  Anyway, I'm trying to capture the IsPostBack event when I select an
                  item within an UpdatePanel. I don't want items running during
                  postback (list, grid population, etc) events - pretty standard: If
                  IsPostBack Then Exit Sub
                  >>
                  But, since AJAX doesn't technically postback (?), the IsPostBack is
                  coming back false...
                  >>
                  So, how can I capture the Async postback done by AJAX? Is there any
                  IsAsyncPostBack keyword and what library is it in?
                  >>
                  Page load process:
                  1. Load drop down menus
                  2. Load data grids
                  >>
                  "Postback process"
                  1. Select datagrid row
                  2. Populate several fields below with further information
                  >>
                  When I select the datagrid row, IsPostBack remains false. I've tried
                  splitting into multiple update panels but now they are all in a
                  singular panel.
                  >>
                  TIA for the help!
                  >
                  Thanks - I did test it and I suppose I wasn't 100% clear. It _does_
                  run a PostBack but it runs through the page initialization once first
                  with IsPostBack=Fals e and then it runs it again with IsPostBack=True
                  >
                  Page_Init() [originally under PreRender]
                  1 If IsPostBack Then
                  2 Exit Sub
                  3 End If
                  4
                  5 loadDropDowns()
                  6 loadIncompleteG rid()
                  >
                  Obviously when I first load the page, lines 5 and 6 run.
                  When I click on the DataGrid, it runs lines 5 and 6 and then runs
                  through again with the break at line 2
                  >
                  Maybe then there's something more wrong with my pages...

                    Comment

                    • BM
                      #6
                      Re: AJAX and IsPostBack

                      On Apr 7, 3:30 pm, "Mark Fitzpatrick" <markf...@fitzm e.comwrote:
                      You may want to play with the timing. Try moving your calls to the
                      subroutines into an event that's further up the heirarchy such as the OnLoad
                      event. You should find that the behavior changes at some point as you get
                      further into the page lifecycle.
                      >
                      Hope this helps,
                      Mark Fitzpatrick
                      Microsoft MVP - Expression
                      >
                      "BM" <moore.br...@gm ail.comwrote in message
                      >
                      news:d04a2cb1-0b23-4f11-aee4-2aa62de11a7c@a1 g2000hsb.google groups.com...
                      >
                      On Apr 7, 1:01 pm, "George Ter-Saakov" <gt-...@cardone.com wrote:
                      AJAX call runs as a POST back. Just test it...
                      >
                      George."BM" <moore.br...@gm ail.comwrote in message
                      >
                      >news:a91154c 5-39c2-4a5f-9c2a-4a586ef9b1cd@u6 9g2000hse.googl egroups.com...
                      >
                      I have a question that seems like it should have a simple answer, but
                      I can't seem to find it by searching...
                      >
                      Anyway, I'm trying to capture the IsPostBack event when I select an
                      item within an UpdatePanel. I don't want items running during
                      postback (list, grid population, etc) events - pretty standard: If
                      IsPostBack Then Exit Sub
                      >
                      But, since AJAX doesn't technically postback (?), the IsPostBack is
                      coming back false...
                      >
                      So, how can I capture the Async postback done by AJAX? Is there any
                      IsAsyncPostBack keyword and what library is it in?
                      >
                      Page load process:
                      1. Load drop down menus
                      2. Load data grids
                      >
                      "Postback process"
                      1. Select datagrid row
                      2. Populate several fields below with further information
                      >
                      When I select the datagrid row, IsPostBack remains false. I've tried
                      splitting into multiple update panels but now they are all in a
                      singular panel.
                      >
                      TIA for the help!
                      >
                      Thanks - I did test it and I suppose I wasn't 100% clear. It _does_
                      run a PostBack but it runs through the page initialization once first
                      with IsPostBack=Fals e and then it runs it again with IsPostBack=True
                      >
                      Page_Init() [originally under PreRender]
                      1 If IsPostBack Then
                      2 Exit Sub
                      3 End If
                      4
                      5 loadDropDowns()
                      6 loadIncompleteG rid()
                      >
                      Obviously when I first load the page, lines 5 and 6 run.
                      When I click on the DataGrid, it runs lines 5 and 6 and then runs
                      through again with the break at line 2
                      >
                      Maybe then there's something more wrong with my pages...
                      I've somewhat solved the problem just by setting the ScriptManager's
                      "LoadScriptsBef oreUI" property to False. It now registers a Postback
                      as such the first time around. Now it just calls my functions 2 or 3
                      times, so I'm at another issue. My pages have stopped throwing errors
                      at least for now.

                        Comment

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