I created two table and make regNo as reference using linq.How to add query extender control dynamically in page.
I would suggest you to go through QueryExtender Class for implementation of this control..
Create the object of this control class and add it to the page at the Page_Init event:
QueryExtender control = new QueryExtender ();
//Set it's properties and Expressions collection or filters etc
Target Control and other as you see in the typed implementation...
this.Page.Form1.Controls.Add(control);
Check this for implementation information
Working with Query Extender control
Related
Hi I'm adding dynamic Controls on button click event,In that I hav dropdown control, I'm raising an event to drop down for selected index change, I made auto post back true, When I'm selecting new item from drop down I'm Losing all the dynamic controls
Every server control that inherits IPostBackDataHandler interface has a LoadPostData method that processes the postback data. When control is implemented by a class (page, form, placeholders, controls etc), that class calls the LoadPostData method and passes the posted data and key to maintain control states.
All you need to do is to re-instantiate / reinitialize dynamic controls before or within page load event each and every time during postback and add this control to page / forms / placeholders. Then the posted data will automatically be assigned to the control by calling the LoadPostData method by the parent control and control event will fire.
check the article and how to write code for dynamic control -
How to maintain dynamic control events, data during postback in asp.net
You have to recreate all dynamically created controls on every postback(in load event at the latest).
You also have to ensure that they get the same ID as before to trigger events and maintain ViewState.
If you know the number of controls to create(which could be stored in ViewState) you can derive the ID from the counter variable by appending it to the control-id. Then you can recreate them with the correct ID in page's init event.
Recommandable readings:
TRULY Understanding Dynamic Controls
Page-Lifecycle
Or you use one of the builtin Data-Bound Control like Repeater that do this automatically. You only have to set their DataSource and call DataBind().
Here are answers of me on similar questions with implementations:
C#
VB.NET (+ C#)
I have a user control which inherits a class. (and I did some coding on Oninit function of this class). I am loading that user control dynamically from server side using the following approach:
Mycontrol dc = (Mycontrol)Page.LoadControl("/Controls/Mycontrol.ascx");
MyPlaceHolder.Controls.Add(dc);
But the problem is that with this the Oninit function of the class inherited by the user control has not been executed. Can any one please tell me why this is happening and what is the solution for this.
Thanks,
According to the MSDN reference for page life cycle events, the OnInit of child controls are called before the OnInit of the page.
That means that you have to add your dynamic controls in the PreInit event to have them in place before the event chain starts. In fact, the documentation for PreInit states that:
Use this event for the following:
Check the IsPostBack property to determine whether this is the first
time the page is being processed. The IsCallback and
IsCrossPagePostBack properties have also been set at this time.
Create or re-create dynamic controls.
Set a master page dynamically.
Set the Theme property dynamically.
Read or set profile property
values.
I've Creted Composite control which has FormView and two custom server control. The Control renders correctly. now when i add control to page from toolbox i want to edit Composite Control's FormView ItemTemplte as we edit ItemTemplate for generic formview (by clicking small arrow head).
any adeas?
When you create an instance of the FormView, programmatically add the templates to the FormView before adding it to the CompoisteControl in the CreateControlHierarchy() method.
Here is an extensive example
I have an ASP.NET page where I call this.DataBind() to bind the controls. I also have various user controls embedded. One has a drop down list, the bind statement gets called for it 2x but the sender the first time is not the drop down list.
Am I using the databind incorrectly? I use databind to get the properties of my page bound to a datasource so that I can use those properties in the declarative code.
In my DropDownList, I added if (sender == dropDownList) which solved the problem
Make sure that none of your user controls are themselves calling .DataBind()
.
I'm trying to use the page control's collection with LINQ.
Whereas this works:
dim l = Me.Controls.OfType(Of TextBox).AsQueryable()
the following return an ArgumentExceptionError:
dim l = Me.Controls.AsQueryable()
I need all the controls. Any help?
Thanks
Have you tried:
Me.Controls.Cast(Of Control)
Out of interest, why do you need it as an IQueryable? Isn't IEnumerable<T> enough for you? (That's the result of Cast.)
The problem with just calling AsQueryable is that the control collection doesn't implement IEnumerable<T>, just IEnumerable.
Also, don't forget that controls can be nested, and just asking the page for it's controls will only tell you about the direct children, but it won't tell you about the controls in those controls:
Locate the web forms controls on a page by walking the Controls Collection
This example finds only the controls contained in the Page object and the controls that are direct children of the page. It does not find text boxes that are children of a control that is in turn a child of the page. For example, if you added a Panel control to page, the Panel control would be a child of the HtmlForm control contained by the Page, and it would be found in this example. However, if you then added a TextBox control into the Panel control, the TextBox control text would not be displayed by the example, because it is not a child of the page or of a control that is a child of the page. A more practical application of walking the controls this way would be to create a recursive method that can be called to walk the Controls collection of each control as it is encountered. However, for clarity, the example below is not created as a recursive function.