DropdownList autopostback

[ggeorgiou01]

Hi,

I have a problem where I have a default.aspx page, with serveral usercontrols in the .aspx page.

I also have a dropdownlist on one of the controls with the attribute autopostback set to true. When i change the selectedindex of this dropdownlist, it always seems to remove the control from the page.

So basically, on change of my dropdownlist (or any other) how do I keep the state of my web-page ? Its starting to get very fustrating!

Many Thanks,
George

 

[SiriusBlackOp]

Is the ViewState enabled for your page and your dd control?

Senior Software Developer

http://www.scoutsft.com

 

[ggeorgiou01]

Thank you for such a swift reply Sirius.

Yes - EnableViewState is set to true for both my user control and my aspx page.

 

[SiriusBlackOp]

Scary... I've never seen a control just get removed from a page.

This control was created in Design time right... not at Run time? Are you sure its Visible property isn't just getting set to False.

Senior Software Developer

http://www.scoutsft.com

 

[IT4EVR]

You said user control and aspx page had view state enabled, but how about the drop down list in the user control?

 

[jbenson001]

Are you creating any of the controls dynamically, or loading any of the user controls dynamically?

 

[ggeorgiou01]

Thanks for all the replys guys. I will post some of my code tommorrow morning when I get into work!

 

[ggeorgiou01]

Morning guys,

So here is my code as promised.

Default.aspx
---------------------------------------------

<asp:ImageButton ID="SupplierBtn" runat="server" OnClick="SupplierBtn_Click" ImageUrl="../Images/Tabs/tab_dim.gif" EnableViewState="true" />

<asp:ImageButton ID="NoteBtn" runat="server" OnClick="NoteBtn_Click" ImageUrl="../Images/Tabs/tab.gif" EnableViewState="true" />

<asp:ImageButton ID="AuthorityBtn" runat="server" OnClick="AuthorityBtn_Click" ImageUrl="../Images/Tabs/tab.gif" EnableViewState="true" />


Default.aspx.cs
---------------------------------------------
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DetailsPlaceHolder.Controls.Add(Page.LoadControl("Controls/Supplier.ascx"));
}
}

#region Event commands

protected void SupplierBtn_Click(object sender, EventArgs e)
{
DetailsPlaceHolder.Controls.Add(Page.LoadControl("Controls/Supplier.ascx"));
}

protected void NoteBtn_Click(object sender, EventArgs e)
{
DetailsPlaceHolder.Controls.Add(Page.LoadControl("Controls/Notes.ascx"));
}

protected void AuthorityBtn_Click(object sender, EventArgs e)
{
DetailsPlaceHolder.Controls.Add(Page.LoadControl("Controls/Authority.ascx"));
}

#endregion



Supplier.ascx.cs
---------------------------------------------

<aspropDownList AutoPostBack="true" ID="SupplierDdl" runat="server" DataValueField="ID" DataTextField="SupplierName" EnableViewState="true">
</aspropDownList>


.....so when i change my selected index on my dropdownlist the control dissapears and drisplay nothin (blank) into my placeholder... any idea's guys ?!

 

[ca8msm]

You have to load all dynamic controls every time the page loads. At the moment, there is only one usercontrol that is being loaded when the page loads.


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[ggeorgiou01]

So are you suggesting the best way of doing this is to load all controls on page_load, then depending on my button onclick, I make the relevant controls visible/hidden ?!

 

[ca8msm]

If I had to create dynamic controls, I would define any logic that decided whether they were needed and if they were, create them. This would all be done in the Page Init event.


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