How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged? RSS

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  ARJ DESIGNS

  Member

  163 Points

  139 Posts

  How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 10, 2013 11:20 PM|LINK

  The below code is a start but it doesn't seem to be working:

  Code Behind

  <Script Runat="Server">
  Sub Page_Load(Source As Object, E as EventArgs)
  	ScriptManager1.RegisterAsyncPostBackControl(ScriptManager1)
  End Sub
  
  Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
  	 If DropDownList1.Text = "HyperLink" Then
  	 	Panel1.Visible = True
  		Else
  		Panel1.Visible = False
  	 End If
  End Sub
  </Script>

  
  Source Code

  <asp:ScriptManager ID="ScriptManager1" Runat="Server" />
  <asp:DropDownList DataValueField="ID" DataTextField="Text" ID="DropDownList1" AutoPostBack="True" Runat="Server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"></asp:DropDownList>
  <asp:UpdatePanel ID="UpdatePanel2" UpdateMode="Conditional" Runat="Server"> 
  <ContentTemplate> 
  <asp:UpdateProgress ID="UpdateProgress1" runat="server" DisplayAfter="1">
  <ProgressTemplate>
  <span style="color: Red">Updating...</span></ProgressTemplate>
  </asp:UpdateProgress>
  <asp:Panel ID="Panel1" Runat="server" Visible="False">
  Test
  </asp:Panel>
  </ContentTemplate>
  <Triggers> 
  <asp:AsyncPostBackTrigger ControlID="ScriptManager1" EventName="Load" />
  </Triggers> 
  </asp:UpdatePanel>

  • Edited by ARJ DESIGNS on Jan 10, 2013 11:21 PM
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  usman400

  Contributor

  3513 Points

  721 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 11, 2013 04:03 AM|LINK

  Code seems alright
  make sure that the drop downs autopostback property is set to true

  Usman Waheed
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  Jugg3rNaut

  Member

  474 Points

  109 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 11, 2013 04:21 AM|LINK

  Take DropDown Inside of your Update Panel

  Beware of bugs in the above code; I have only proved it correct, not tried it.
  -------------------------------------------------------
  Contact-Info:Adils.kiet@gmail.com
  
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  ManikandanUl...

  Participant

  850 Points

  253 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 11, 2013 04:45 AM|LINK

  put dropdownlist inside the updatepanel.

  Manikandan Ulagu
  Click "…Mark As Answer" if my reply helpful....
  
  
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  ARJ DESIGNS

  Member

  163 Points

  139 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 05:50 PM|LINK

  DropDownList AutoPostBack is set to "True" and is now inside UpdatePanel.  The Panel is still not changing from Hidden to Visible OnSelectedIndexChanged.

  Is the Panel inside of this UpdatePanel coded correctly?

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  TheDirtyBird

  Participant

  806 Points

  339 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 05:56 PM|LINK

  Comment out all the AJAX and see if it works.

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  ARJ DESIGNS

  Member

  163 Points

  139 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 06:10 PM|LINK

  What do you mean? All of my code is in the original post.

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  msmk

  Participant

  776 Points

  158 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 06:41 PM|LINK

  I tried out your code and it works fine, even with the dropdownlist out of the update panel. The only thing I can think of is make sure that the text in your dropdownlist matches the code exactly - "HyperLink" and not "Hyperlink" or "hyperlink"

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  ARJ DESIGNS

  Member

  163 Points

  139 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 07:18 PM|LINK

  If I view the page in Internet Explorer, I get following error message appears:

  Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object.
  

  • Edited by ARJ DESIGNS on Jan 14, 2013 07:47 PM
  • Edited by ARJ DESIGNS on Jan 14, 2013 07:48 PM
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  ARJ DESIGNS

  Member

  163 Points

  139 Posts

  Re: How do I hide/show asp:Panel on asp:DropDownList OnSelectedIndexChanged?

  Jan 14, 2013 07:47 PM|LINK

  Is there anything that I need to do differently if I am using a Master Pager File?

  • Edited by Pengzhen Song - MSFT on Jan 24, 2013 06:18 AM
  • Edited by Pengzhen Song - MSFT on Jan 24, 2013 06:18 AM