Web Forms :: Adding User Controls To A Page Dynamically
Feb 6, 2010I need to set some attributes on user controls that I'm dynamically adding to a page placeholder. Is this possible?
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I need to set some attributes on user controls that I'm dynamically adding to a page placeholder. Is this possible?
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Adding user controls dynamically to aspx page
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I am new to ASP.NET And I am have THE hardest time understanding how to work with forms in ASP.NET. Here's what I am doing:
Dynamically add User Controls to a PlaceHolder based on some int value (which currently is passed in a HiddenField).Fire an event if the WebControls inside of the User Control change, then handle that event in the Main Page (i.e. save the input to DB)When the user clicks the "Next/Continue" button, the next controls for the next page are loaded. And I guess maybe I just can't seem to get how things work in ASP.NET, because I am really struggling with the general idea of how ASP.NET flows.
Should I be dynamically loading the controls in Page_Init, or Page_Load? Or should I load the controls when the buttonclick event is fired?Do I have to add the axCtrl.OnDataChange += new EventHandler(HandleAxControlDataChange); line on Page_Load? Or should I put this in When I first load the UserControl, I need to initialize some WebControls within the UserContorl. Is there a way to know if I have loaded new user controls into my placeholder? I can't use Page.IsPostback, because after the first page, every page is a postback from the buttonclick.
Here's what I have:
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Here's the markup from my ASPX file...
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I have a usercontrol (ascx) that I want to dynamically add to a page.
Neither the control nor the page has a namespace (thanks crappy vendor).
When I use the following, it tells me it cant find the "type or namespace"
StayTunedControl = (UserControler_StayTuned)LoadControl("~/UserControler/StayTuned.ascx");
Page.Controls.Add(StayTunedControl);
StayTunedControl.StayTunedID = Convert.ToInt32(IncludesStayTunedMeta.Value);
After some tweaking to the namespaces, etc, I am now at a point where the 3rd line above generates the following error:
'System.Web.UI.UserControl' does not contain a definition for 'StayTunedID'
I was hoping that casting StayTunedControl as type (UserControler_StayTuned) would fix this.
<% @
Register
src="myControl2.ascx"
tagname="myControl2"
tagprefix="uc4" %>
Page_Load(object sender,
EventArgs e)
{
myControl2 mc = new myControl2();
//is there anything wrong with the preceding way? Why ever use LoadControl?
Control myLC = LoadControl("myControl2.ascx");
//Why ever do it the LoadControl way?
}
I am trying to dynamically add a queryextender expression to the page. something like, when the user clicks a button, we need to add a OrderbyExpression. The following is the code used. It works when added in Page_Load but doesn't when added on a button click event. Upon button click the page just reloads and ignores the filter condition.
OrderByExpression obex = new OrderByExpression();
obex.DataField = "ProductName";
obex.Direction = SortDirection.Descending;
ThenBy tb = new ThenBy();
tb.DataField = "UnitsInStock";
tb.Direction = SortDirection.Ascending;
obex.ThenByExpressions.Add(tb);
this.q.Expressions.Add(obex);
where queryextender1 is the ID of the queryextender
I am adding controls dynamically in my webpage.
I add them in onload method.
everything is working fine..
But I m a bit confused about how it works..
I have read in so many articles that all controls get their values from viewstate before load event. Then how my dynamically added controls get their values when i am adding them in OnLoad event ie after LoadPostData event.
I have a usercontrol that uses a callback to update itself. If I add the control to the aspx page everything works fine. However, when i add the control using Page.LoadControl and Control.Add on a Placeholder i get the following error: "The target 'ctl00$ContentPlaceHolder1$ctl00' for the callback could not be found or did not implement ICallbackEventHandler". I tryed assigning the ID of the control also which failed with the same error. I am using asp.net 2.0.
View 11 RepliesI am using jquery ajax method to get data from a web method and present data using DOM(similar to that of google search results).B'coz the data returned from the web method is huge I want to paginate the results.For that I need to create buttons corresponding to the page numbers based on the no. of records the web method retrieves from the database.So I have taken a div on the page.In the web method ,as soon as I can find the number of records obtained from the database,I want to create the buttons and add to this div and display 10 records per page.As far as I know, it is not possible to access anything that is placed on the asp.net page from Web method.In that case how do I paginate the results?
View 2 RepliesI am dynamically adding controls to a page with an updatepanel. The controls do trigger a post back but their events do not fire.
For example:
LinkButton link =
new
LinkButton();
link.Height = 45;
link.Width = 250;
link.Font.Underline =
link.Font.Bold =
link.ValidationGroup = "NoValidation";
link.Click += new
EventHandler(EventDoesNotFire);
I have set a break point on the Load_Page and in the EventDoesNotFire method. The Load_Page fires, but it never enters the EverDoesNotFire method.
In a User Control, I need to add a Div to the end of its parent's page. I've done this in a number of ASPX pages, where I put the code to generate the Div and its contents in the page's PreRender event handler, and it works fine. But when I try to do the same thing in the PreRender event handler for the User Control, I get the following error:
The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases.How do I accomplish this in a User Control?
I am using ASP.Net 2.0 with Ajax.
I am working on a pretty heavy page in an application and the scenario is:
There is a Tab control in the page, having four tabs. These tabs individually consist of different user controls and other asp controls. Most of these usercontrols in turn consist of other user controls. Every user control contains huge javaScript functions which validate them, populate controls and call web services.
What I am trying to achieve is to load only the Tab and its user controls on the page load and when the user clicks on a specific tab, load its contents (User controls) dynamically. Once that is done, I am setting the tab's postback to false to prevent loading it again once loaded.
I tried to achieve this by making the user controls in the other tabs - visible="false" in the markup and loading them from server side on some specific event. But that causes the javaScript functions in those user controls to give errors ('Object expected') when I go to that tab.
If I set the user controls in the other tabs to visible true, then no matter what; the page life cycle goes to each registered control and loads every subsequent control in that web user control which makes the main page slow (on loading and every postback).
The position of the Tab and the inner user controls is fixed. Although I am taking care that no data is populated unnecessarily on the page and user controls on hidden tabs, I dont want the tabs to get loaded altogether unless requested. If I load them on runtime, their corresponding javaScripts start giving errors.. note that I am not generating the controls on runtime, they exist in the page design. I just dont want to load them dynamically
I'm developing an ASP.NET application with C# and Ajax.I have a page that holds user controls loaded dynamically. I need to pass some data (integer values and some strings) to the user control that has been loaded dynamically.Now I use Session to pass these values, but I think I can use another way; something like VIEWSTATE or hidden input.What do you recommend me?The fact that I load the controls dynamically is important because controls are loaded on every postback, and I can't store any value on controls.
View 9 RepliesAdd 2 user controls and display them on your default aspx page. One control will be a simple list of store contact information. The other control will be a featured product control which displays a featured product of your choosing with an image and a description.
So i created a web user control page something like stewiecontrols.ascx
And I want to how to register the page <@control ...... src="" prefix name="" prefix tag="" /> the rest of the code in html <div> ..... </div> tags.
My question is this. I'm creating a master page and the default page is created using master page. So how do I register this .ascx page on default page. Should I register the .ascx page under master page or how. I want the user controls to only be shown on default.aspx page.
I am trying to add a user control into a div at runtime. I can add the control no probelem but it overwrites the previous control added.Basically, I am trying to add passengers to a travel system - the passenger details are in the user control and I don't know in advance how many there will be. I have an add new passenger button which should append the new user control into the div without overwriting the previous passenger. The code is c#/.net 4. I have tried to save the control data into viewstate and re add it with the new one but that also doesn't work. Here is a snippet of the code I'm using
foreach (Control uc in p_passengers.Controls) {
Passenger p = uc as Passenger;
if (p != null) {
p.SaveValues();
}
}
however, p.SaveAs() (just writes the control values into ViewState) is never hit.
Ok, so I'm adding linkbuttons to a page dynamically on page_load.I had it to where the link buttons were redirecting to a page with a query string attached. I was attempting to use the AjaxToolKit's AjaxFileUploader and ran into issues with existing query strings.
So what I'm trying to do now is handle the click event of the linkbutton server side, set 2 session variables and then redirect the page to the same page, but with out appending a querystring so the ajaxfileuploader will work correctly.Here is my linkbutton code:
vb Code:
Dim Lin As New LinkButton
Lin.Text = dr("DeptDesc").ToString
Lin.CssClass = "deptlink"
Lin.ToolTip = CDate(dr("MeetingDate").ToString).ToFileTime.ToString
'Lin.OnClientClick
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I know I have Lin.PostBackURL and Lin.setAttribute(...). It didn't work with just setAttribute and I saw a post online about someone setting the PostBackURL and it working...
I am working on a page where user controls are dynamically added to the page and refreshed with a timer in an updatepanel.
Since I already coded dynamic user control loading into the page, I would also like to implement *some* form of dynamic layout method for those controls. I was thinking coordinate values.
I have used Top and Left properties on panels before to achieve this functionality in my windows forms applications but since this is a web application things are different.
I realize I can do the whole "absolute positioning layout model" override in Visual Studio but as far as I know this only benefits me at design time. Is there a way to programatically trigger that behavior?
I looked at the silverlight Canvas and how you can pass offset values in with your controls. Something like that would be great, but this isn't Silverlight, lol. I also considered a web method to return globs of html tags to fill the area between these controls.
This is a page that would be reused over and over from client to client so this is why I would like to get this dynamic layout working. It would save me much effort later on.
I have the following code which adds a label and a gridview to an asp.net page:
GridView grd = CreateGridView(kvp.Key.Text);
Label l = new Label();
l.Text = "some text";
l.CssClass = "this has no effect";
placeHolderResults.Controls.Add(l);
placeHolderResults.Controls.Add(grd);
Two questions really:As the page will have a multiple and unknow quantity of Label + Grid pairs I'm looping through the above code, is this the best way to add the controls to the page?I cannot style the label? How do you do it? Looking at the HTML which is created, the label turns out to be a SPAN.
What I am trying to do here is I want to add the dynamically created labels in the Panel on the Webpage and not directly on the Webpage. My panel has scroll bars and thus when I scroll horizontally or vertically only the background moves whereas the labels are static to the page.
And some labels are even visible on the panel borders on scrollbars (some on the page outside the panel) which are suppose to be placed inside the Panel. So when I scroll either of the ways even the labels should move along with the background image.
So how can I make these labels stick to the Panel and not the Page? How do I do it?
My C# web app requires the user to enter automobile information. The user can add information for one auto, or more (max 20).
My page has these text fields: Car Number, Car Make, Car Year, Mileage, VIN I have a button that allows the user to "Add More Cars" is to allow the user to add more than one car.
When the user clicks "Add More Cars", how can I dynamically display the text boxes, and keep track of how many cars the user has added (in order to load them to an array and write to database)
I have a page where a user can add any number of a specific custom control by clicking a button and delete any of them by checking a "delete" box and clicking the delete button. This custom control has a dropdown, 3 radiobuttons, 2 text boxes and 2 checkboxes. The anomaly occurs when you add at least 2 controls, then delete any of them but the last one.
When each control is rendered the name and id attributes are autoincremented to make them unique however, in the above casewhen the custom control is actually renedered to the page the name attribute has an index that is 1 higher than the id. For example:
here is the name and id of the problem radio button: name = ctl00$ContentPlaceHolder1$PreOpUpdatePanel$PreOpStatcompareinout1$AllInOut but the id = ctl00_ContentPlaceHolder1_PreOpUpdatePanel_PreOpStatcompareinout0_All
Now I am sure that I am doing somethign wrong but I just do not know what. Since the controls are added dynamically I have to recreate them on each postback so that the postback data can repop the fields. However, when the user deletes then the postback event makes me recreate all of them, then I have to remove the controls the user requested to be deleted. At this point the auto generated index is incorrect so the nextpostback will lose the data so I have to manually renumber the control IDs. Now this seems to work on all other controls within my custom control except for the radio buttons.
I have a web of ashx,in it
string ipSrc;
if (context.Request.UrlReferrer == null)
{
ipSrc = "";
}
else
{
ipSrc = context.Request.UrlReferrer.ToString();
}
string os=hbc.Platform;
string browserInfo = hbc.Browser + hbc.Version;
DAL.InsertData_OleDb(context.Request.ServerVariables["REMOTE_ADDR"], ipSrc, WebTitle, os, browserInfo);
I need to let my user add rows dynamically to a table, and after doing some research, it seems the best way to do this is through a GridView bound to a DataTable. However, I'm really struggling adding dropdownlists to the datatable, and this showing them in the gridview.
Here's the design I want:
ddl1 | ddl2 | ddl3 | ddl4 | ddl5 | ddl6 | ddl7 | textbox
When the user opens the form, he or she will be presented with one row. ddl2 etc will be populated when ddl1 is selected etc etc. When appropriate, the textbox will be enabled allowing the user to enter a comment (this is to report errors, and since users are, at best, not to trust to write the same thing twice, I need to use ddls.
Now comes the question - how do I add a ddl to the datatable? I've tried several ways, but I cannot get them added.
I'm looking to add controls dynamically to a table across multiple functions. I'm trying to convert this from a C# app to a web app using asp.net, though this is my first time using asp.net with no web development background. I read the creating tables dynamically in the FAQ but I'm still not sure how to do this.
When pressing the submit button on my form, it will create a table in a place holder. Eventually I would like it to generate urls based on the users input and do this in a function other then the one I created my table in.
In my C# app I was able to add text to a listbox using: lstOutput.Items.Add("Text"); across multiple functions but I'm having trouble doing this with a table.
I understand that my table is a local variable in the submitButton_Click function, but how do I make it global to add rows, cells and controls to it in other functions?
My current code which doesnt work:
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i am kind of new in the .net world. I would like to know how you can add a link column with an image to a datagriid.
P.S. i am using Visual studio 2005.