I want to fill an updatepanel with new dynamic controls in response to a button click.
However, I also want to be able to access the values of these dynamic controls in response to an event in one of the controls.
Specifically, I want the button to bring up two dropdownmenus. One of the menus (or both if need be) is in another update panel. I want the first menu in the update panel to change its data in response to a value getting selected in the other menu.
I think my problem is that when I cause a postback with one dropdownmenu I lose the other dropdownmenu because I created it in the button_click handler.
I know I should create dynamic controls in the Page_Init method (or so ive heard) but I only want the controls to show up if the button is clicked. There are other buttons on the page which need to create a different set of dynamic controls.
Thanks.
There are a lot of ways you can handle this, and which approach to take really depends on your project's requirements and your available resources.
The smoothest way to do it that would generally provide the best user experience would be to use a Javascript technique to hide and show controls as the page required them. JQuery is the library I would recommend for this. On the most basic level, you simply wire the control's activation (such as a button_click event) and hide or show a div containing the dynamic content as necessary, like so:
$("#control").show();
// and
$("#control").hide();
Alternatively, you can do this in C# by using the Visible property on many of the normal web controls for ASP.NET. The usual code-behind approach would look something like this:
private void btnControl_Click(object sender, EventArgs e)
{
var dynamicControl1 = FindControl("dynamicControl1");
dynamicControl.Visible = false; // or true, as the case may be
}
This particular approach is mostly attached to code-behinds, though, which I would encourage you to avoid if possible. They are practically impossible to test and will make projects a pain to work in. You can use a similar approach in the MVC3 framework, of course, it will just be a little different how you send and receive the control you are setting to not be visible. The other benefit this has that is kind of nice is that if something is set to not be visible, it tends not to even be displayed in the HTML generated by the templating engine (YMMV depending on the engine, but I know this is true in Razor). So someone viewing the source of your webpage won't be able to see inactive controls, which may or may not be something that appeals to you.
EDIT: I see the problem is less to do with how to display these things, and more with how to create and read them back given on-the-fly input.
I'm sure there's a way to do this with Javascript (which would more than probably be the cleanest and best way to do this), but I'm not good enough with JS to know the answer to that one. The way you would handle this in ASP.NET is make the div you're going to add controls to server-side (by using runat='server', then add what you need there. Again, the trivial code-behind approach would be something like:
private void btnControl_Click(object sender, EventArgs e)
{
foreach(var checkBoxChecked in chkBoxes.Where(x => x.Checked))
{
div.Controls.Add(new WebControl()) // or whatever the heck else it is you need.
}
}
This presumes that you have an IEnumerable<CheckBox> to iterate over, of course. You may also want an IList<WebControl> to keep track of all the junk you're adding. You will also need to make sure the CSS is applied properly to the div for the controls you're adding. And again, code-behinds are pretty awful and I use the example only because it'd be easy to spin up in a project to test for yourself.
Related
good sirs!
I've been messing around with the next scenario:
First, I have a webform structured as a WebForm containing a DevExpress ASPXPopUpControl and some other controls. Inside the PopUpControl there is a UserControl (lets call it ucA) containing some other controls and a UserControl (called ucB) that contains a cursed ASPxHtmlEditor (added because it's a new requirement).
When the user hits a button on main webform I show the PopUp (originally was a jQuery dialog but since HTMLEditor messes up with jQuery I've been forced to break the standard and use the popup) which contains the ucA. The user fills some fields in ucA and hit the save button. After user hits, I save some dataz and at this point I need to recover a textbox value placed in the webform.
I'm using Parent.FindControl["myTextBox"] but it considers the popupcontrol as parent. When I was using jQuery (before implementing the editor) it worked like a charm.
I feel it's something trivial but thrust me when I say that this stole many hours of research.
Thanks in advance.
EDIT I forgot to mention that I want to look for another UserControl at main webform. This uc its used to display core messages to the user so when he hits the save button, save happens, popup is closed and i look (Parent.FindControl("myUCMessageBoard")) from the ucA for the usercontrol to display a "Transaction complete" message.
I'm thinking you're going to have to do something a little hacky, by using ViewState. If I understand correctly, you are trying to get access to a TextBox's Text on the Web Form, from a UserControl nested within a PopupControl (so you can't traverse all the way up to Web Form Level).
So, what I'd do at some point in the process is store the text in a ViewState variable that you can access from the User Control. It's not optimal, but since you're already hacking to get it to work, what's a little more hacking?
You should expose all controls from ucA as properties, then look for the control inside the DevxPopup the same way you doing. Given that all the controls that you need at the ucA has properties to access them, you could do all the logic you need!
Example:
public ucA : UserControl
{
public string myTextBoxText
{
get
{
return ((TextBox)Controls.FindControl("myTextBox")).Text;
}
}
/*And lot of controls*/
}
Then you looking for the popup at the Form
var ucA = (UcA)Form.Controls.FindControl("myPopup").Controls.FindControl("myucA");
ucA.myTextBoxText = /*Do stuff here with the text*/
Hopes this help you!
Is it possible to keep a control (Panel) always over all other controls even if they also use Control.BringToFront()?
I tired to use BringToFront itself, but it seems that this loose its effectiveness if another control under this control also uses this command.
It would help if you try to explain what are you trying to achieve. We might be then able to better convince you, that you are doing something very wrong :)
Anyway, no matter what trick you do, the other control may use the same trick to override you.
You can get step ahead for example by handling parent control's Layout event to force your control back to front. The Layout event is trigerred (among other) when child controls' Z-order is changed.
private void Form1_Layout(object sender, LayoutEventArgs e)
{
panel1.BringToFront();
}
A dirty way of dealing with this is setting a timer and everytime it ticks use the .BringToFront() method on the control, you can also add multiple controls you wish to perform this on and can arrange them however you like.
I'm currently working on a web-based game using ASP.NET and C#. Previously, I've been just organizing the various game screens(start, hi-score, results, etc) into individual Panels nested within a main UpdatePanel and showing/hiding the appropriate Panels as the game progresses. However, I've severely underestimated the scale of the game and I'm gonna have to break it down to more manageable chunks.
My idea now is to have a Main.aspx with an empty UpdatePanel and I'll load the various screens as individual .aspx files into it. Kinda like with WinForms I think, when you create another new WinForm and add it to the current parent form.
I've been trying to find how to get about doing this in the code-behind, but I'm still at a lost. I could probably do this with Response.Redirect, but then there would be the usual flicker when the new page loads, which is something I want to avoid.
I did come across something interesting called a UFrame but that seems to work in the HTML instead of the code-behind.
I appreciate any help or suggestions in this matter, and apologize if this has been asked before. Thank you.
Edit: With regards to womp's answer, .ascx seem to be a step in the right direction for me. I successfully got my Startscreen control control up and running inside the Main.aspx. However, another problem has popped up, where the screen just goes blank when I try to add another usercontrol to a panel inside Main.aspx upon a button click.
The event handler I have for a button in the Startscreen control is:
protected void Btn_Arcade_Click(object sender, EventArgs e)
{
this.Parent.Controls.Add(LoadControl("Arcade.ascx"));
}
I'm not too sure if there's anything wrong with that, but the Parent in this case is basically what I called the GameContentPanel that resides within Main.aspx's UpdatePanel.
I don't think it's a problem with the HTML fudging up either, since I tested it by loading it first instead of the Startscreen, and everything showed up fine.
I've also tried loading both controls together at the start in Main.aspx, and both controls load correctly as well.
Can the "screens" be .ascx usercontrols? You can load a usercontrol into a panel using LoadControl("~/path/to/myControl.ascx"), and then those controls can take part in the lifecycle of the main page.
If they really have to be in separate .aspx pages, then you might need to look at using an iframe, or else maybe rethinking your approach. Webforms apps were designed to have lots of things happening inside the context of one page/form, and not transferring control back and forth to multiple pages.
I'm working on an application that presents the user with varied data, depending on the object being viewed. The objects are all of the same interface just with extended properties beyond once distinguished.
I'm looking for the "best" way to display a type-dependent control to the user. I would like to use tabs but I'm stuck with .NET 2.0 and from what I can gather the only way to hide/show tabs are to remove them and re-add them. That might be the best way but that leads to issues regarding blinking of the GUI components, keeping tabs on the active tab when reloading, etc.
I could make custom controls for each and either have them all loaded and hide/show when necessary (which I have done in the past on projects), or dispose and re-instantiate them...
To clarify best, I would say the closest balance between code elegance and program efficiency.
I have used and have had the best luck with loading them all and then showing/hiding the ones needed.
Disposing and re-instantiating everything always made things very messy.
In order to not have load time be horrible, you can instantiate them on first use. Something like:
IView LoadView(Type dependantType)
{
// get the view or create one
IView view = GetView(dependantType);
if (view == null)
{
view = InstantiateViewAndAddToForm(dependantType);
AddView(view);
}
//
// do some binding to your model or whatever here
//
// make the correct view visible
foreach (IView v in Views)
view.Visible = v == view;
}
Could you just create a panel for each object and have a dictionary associate the object type and the panel?
You could just tell the panel to bring to front if they are all the same size, or set all Panels.Visible to be false, and just set the one you need to be true.
I have used DockPanel Suite for applications that require multiple tabs.
It is an open source project, so you can actually modify the code if you wish.
The Suite has many functions, however, if you can just use the Tabs.
I've seen two threads here about TDI & C#. Both of them didn't really answer the questions I have ...
Since TDIs are pretty much like a standard nowadays, I can hardly imagine, that I have to buy a special control (like AvalonDock or SandDock).
This must be possible with built in the tab-control(?) somehow! I don't need special features like dock- and draggable tabitems. Just open every form in a new tab. Thats it.
Like putting every forms content controls into user controls and by request (button, menu click ...) add a new tab and put the corresponding user control on it ... something like this.
How would you do it? This can't be THAT complicated (even for me) or am I missing something?!
thanks a lot!
Maybe Josh Smith's article on MVVM can give you an idea how to design such user interface. Example being built there is kinda tabbed document interface so you can use it as a starting block.
It's not that hard. It seems hard because there are a lot of different ways to do it.
Try this:
<TabControl x:Name="documentArea"/>
Handler for AddForm button:
private void AddFormClick(object sender, RoutedEventArgs e)
{
object form = GetNewForm();
documentArea.Items.Add(form);
}
That's it. You have to implement GetNewForm() in one of two ways. Have it return a user control that displays the form.
OR better yet, have it return your document that you want to display. Use a DataTemplate to select the controls to use for displaying this document. This method is going to be more complex to set up.