I need to modify a 3-level dropdown <select> menu to function directly on the page and not inside an iframe (that's how we currently do it).
Here's how this menu works:
User makes a selection in 1st dropdown
Choices in 2nd dropdown are filtered based on what's chosen in 1st one; user selects from one of these choices
Choices in 3rd dropdown are filtered based on what's chosen in 2nd one; user selects from one of these choices; this last dropdown submits the form and redirects the user to another page, also passing the values from all three dropdowns.
Right now, this is accomplished using an <iframe> that queries an ASP.net database and reloads itself after each selection.
I really need it to work without using an iframe. Not sure what the most elegant way to approach this is ...
If you're open to using the ASP.NET Ajax Toolkit, they have a cascading dropdown control which does what you ask. One additional benefit, because it uses Ajax it does not have to reload the page after each selection in the dropdowns.
i think you'll probably need to use the 'onSelectIndexChanged` even on the DropDownList control. something like...
<asp:DropDownList id="ddl1" runat="server" OnSelectedIndexChanged="ddl1_OnSelectedIndexChanged"></asp:DropDownList>
<asp:DropDownList id="ddl2" runat="server" OnSelectedIndexChanged="ddl2_OnSelectedIndexChanged"></asp:DropDownList>
<asp:DropDownList id="ddl3" runat="server" OnSelectedIndexChanged="ddl3_OnSelectedIndexChanged"></asp:DropDownList>
Page_Load()
{
if(!IsPostBack)
{
ddl1.DataSource = getdata();
ddl1.DataBind();
}
protected void ddl1_onSelectedIndexChanged(object sender, EventArgs e)
{
ddl2.DataSource = getData(ddl1.SelectedValue);
ddl2.DataBind()
}
protected void ddl1_onSelectedIndexChanged(object sender, EventArgs e)
{
ddl3.DataSource = getData(ddl2.SelectedValue);
ddl3.DataBind()
}
protected void ddl3_onSelectedIndexChanged(object sender, EventArgs e)
{
Response.Redirect("SomePage.aspx?ddl1="+ddl1.SelectedValue+"&ddl2="+ddl2.SelectedValue+"&ddl3="+ddl3.SelectedValue, true);
}
You could put all 3 of them in an UpdatePanel.
I am sure your changes are already making the page refresh.
Putting them in an update panel will make only the panel refresh, causing a partial page update.
This uses ajax to do the job internally.
Here is a update panel example, if you want one.
P.s.: Asp.net's method to create a <select> is a DropDownList control. I hope you are already using those, if not convert your selects to a dropdownlists.
Related
I made researching about this subject I could not find proper answer.
In my default.aspx page, I have a treeview. Codes are in default.aspx like below:
protected void Page_Load(object sender, EventArgs e)
{
}
protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
Control ucont;
if (TreeView1.SelectedNode.Value == "Yeni Dönem")
{
ucont = LoadControl("usercontrols/yenidonem.ascx");
PlaceHolder1.Controls.Add(ucont);
}
else
{
ucont = LoadControl("usercontrols/tabloktar.ascx");
PlaceHolder1.Controls.Add(ucont);
}
}
I load user controls dnynmicaly. User controls are have button control. I can not fire user control's button click when I load it dynamcally. How can I solve this ?
Thanks.
First of all, I would not recommend adding control dynamically later than in Page_Load event. Other things to remember is that You should add it on each page load and assign unique ID value the control that does not change between postbacks.
In this case, the easiest way would be to always add both controls to the page and show appropriate one using Visibility property.
If that's not suitable for You, try to move the code from TreeView1_SelectedNodeChanged to the Page_Load event and load appropriate control on each postback until it should be changed to another one.
I haven't tested this, so if You have any issues when using thise answer, let me know in the comments and I'll try to help.
I am using a modular popup to show gridview in a popup. Now I want to implement paging of this gridview. When I click on the page number the popup disappears. How do I avoid it? I want it to disappear only when clicking close button.
I assume that you're using the ModalPopupExtender from the AjaxControlToolkit.
If you're posting back you always need to call ModalPopupExtender1.Show() in codebehind when you want it to stay visible.
You could simplify it by using Page_PreRender if you have many events and you don't want to remember this always:
protected void Page_PreRender(object sender, System.EventArgs e)
{
// change "this" to somewhat appropriate for example your GridView
// "this" makes sense for example in a UserControl
if (this.Visible) {
this.ModalPopupExtender1.Show();
}
}
I have an asp.net application for membership management. One page needs to have a gridview which is populated based on a dropdown list of statuses. I initially thought about hard-coding with a Select Case, but then remembered that the dropdown list is databound and needs to be dynamic (because the admin-level users have another page to change the statuses). I'm still new at this, and my searches are not turning up anything.
Any links or examples would be helpful. Thanks.
I would suggest to use OnSelectedIndexChanged event of dropdownlist for your purpose with AutoPostBack property set to true, something like this
<asp:DropDownList runat="server" ID="ddlStatus" OnSelectedIndexChanged="ddlStatus_SelectedIndexChanged" AutoPostBack="True"></asp:DropDownList>
And on your code behind page you can bind your grid differently for different selected values in your event handler, something like this
protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e)
{
if (ddlStatus.SelectedItem.Value == "RequiredValue")
{
// bind grid in some way
}
else
{
// bind grid in some other way
}
}
This will work irrespective of your binding the dropdownlist options dynamically or having them hard coded.
Currently struggling with a problem that I've encountered variations on in the past. At the moment a worthwhile solution escapes me, but it seems such an obvious issue that I can't help wondering whether or not there's a "best practice" approach I should adopt.
Without code, here's the issues in a nutshell:
page has databound control (a repeater) which isn't populated until user inputs data and clicks a button.
Repeater item template contains a button
User clicks button, page posts back. On load, the repeater is actually empty so event is never handled because the originating control no longer exists
Go back to the beginning of wretched cycle
I've confirmed that this is the problem because if you provide the repeater with some static data on page load, everything works fine. But of course that's no use because it has to be populated dynamically.
Is there a commonly approved way round this headache? I can store the data in session and re-use it on page load, but it seems terribly clumsy.
Cheers,
Matt
If the event is being fired by a button within a repeater then this would bubble up to the repeaters ItemCommand event. Using a buttons CommandName and CommandArgument parameters you can then identify which button was clicked and act accordingly. Below is some basic markup and code behind to demonstrate the approach:
HTML:
<asp:Repeater ID="rptTest" runat="server" onitemcommand="rptTest_ItemCommand"
onitemdatabound="rptTest_ItemDataBound">
<ItemTemplate>
<p>
<asp:Button ID="btnTest" runat="server" />
</p>
</ItemTemplate>
</asp:Repeater>
<asp:Button ID="btnLoad" runat="server" Text="Load" onclick="btnLoad_Click" />
Code behind events:
protected void rptTest_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
Button button = (Button)e.Item.FindControl("btnTest");
button.Text = string.Format("Button {0}", e.Item.DataItem.ToString());
button.CommandName = e.Item.ItemIndex.ToString();
}
protected void rptTest_ItemCommand(object source, RepeaterCommandEventArgs e)
{
Response.Write(string.Format("Postback from button {0}", e.CommandName));
}
protected void btnLoad_Click(object sender, EventArgs e)
{
List<int> list = new List<int>();
list.Add(1);
list.Add(2);
list.Add(3);
list.Add(4);
rptTest.DataSource = list;
rptTest.DataBind();
}
Hopefully i've understood the problem and this helps.
If any of your controls are created dynamically, then they have to be recreated during post back in order for the events etc to get hooked back up.
If this is the case, take a look at a control built by a guy named Denis Bauer. We use this with just some slight modifications and it's perfect.
I am building a pop-out menu, and the client wants it to be able to pop out continously based on a heirarchy.
For example, the first pane is a list of options. When they are hovered over, another pane should pop up next to it with the next level of options, and so on until the last level of options is reached.
I can handle all the javascript and stuff, but I can't think of a way to continously embed repeaters inside repeaters. I know I could do it once by putting a repeater inside another, but then I would only have two layers.
I need to be able to continously embed repeaters for each layer of options, or achieve this with a similar technique using a different control.
Any help is great, thanks!
You won't be able to build this in mark up. You'll have to add the controls dynamically in your code behind by building the Repeater for each level and adding it to the previous Repeater's template. It will require a full postback for each option selected because the nested Repeater could potentially be of different depth depending on which option is chosen.
You might be better off doing this all client-side, though, using AJAX and javascript. When an option is chosen, fire off an AJAX request to see if that option has sub-options. If it does (return them), then dynamically build the new options control using javascript and add it to the page. When a different option is chosen, you'll remove the elements from the DOM holding the previously chosen options sub-options.
If you can get your menu out in form of a list of MenuItem objects, each of which has a (sometimes empty) list of sub items (and I really mean a List<MenuItem> here... we're going to use this collection as a datasource for a sub-repeater, so it needs to implement IEnumerable<T>) as a property MenuItem.SubItems, you could probably make use of a UserControl that loops out one menu level, and calls upon itself for the next.
In the UserControl you'd have something like this:
<li><a href='<%= this.MenuItem.Url %>'><%= this.MenuItem.LinkText %></a></li>
<asp:Repeater ID="UCRepeater" runat="server">
<HeaderTemplate>
<ul>
<ItemTemplate>
<menu:MenuItem ID="MenuItemUC" runat="server" />
</ItemTemplate>
<FooterTemplate>
</ul>
</FooterTemplate>
</asp:Repeater>
The UserControl in the ItemTemplate is the same one, so for each item template the same thing will be rendered.
Below is the Code Behind for this user control, and this is where the magic happens:
public partial class MenuItemUserControl : UserControl
{
// A property we'll use as the data source
public MenuItem MenuItem { get; set; }
protected void Page_Load(object sender, EventArgs e)
{
// If the current menu item has sub items, we bind the repeater to them
// And by the way, there is no use doing this on every postback. First
// page load is good enough...
if(!Page.IsPostBack) {
{
if(MenuItem.SubItems.Count > 0)
{
UCRepeater.DataSource = MenuItem.SubItems;
UCRepeater.DataBind();
}
}
}
protected void UCRepeater_OnItemDataBound(object sender,
RepeaterDataBoundEventArgs e)
{
// Every time an Item is bound to the repeater, we take the current
// item which will be contained in e.DataItem, and set it as the
// MenuItem on the UserControl
// We only want to do this for the <ItemTemplate> and
// <AlternatingItemTemplate>
if(e.Item.ItemType == ListItemType.Item ||
e.Item.ItemType == ListItemType.AlternatingItem)
{
var uc = (MenuItemUserControl)e.Item.FindControl("MenuItemUC");
if(uc != null)
{
// This is the magic. Abrakadabra!
uc.MenuItem = (MenuItem)e.DataItem;
}
}
}
}
So in order to get this to work, the only thing missing is really a nice way of getting your data out as a hierarchical list of MenuItems. This I'll leave to your data access layer (and it would be cheap easy using LINQ to SQL or Entity Framework... ;) )
DISCLAIMER: This code is provided as is, and I wrote it off the top of my head. I have not tested it, but I think it will work - and if it doesn't, it could at least give you an idea of how to solve the problem. If you have problems, please post them in comments and I'll try to help out - but there are no promises of success here. Just a willingness to help out! =)