Custom Server Controls :: UpdatePanel Not A Container In Design Time?
Nov 3, 2010
I have a custom Panel with attribute Designer(typeof(xxxMainPanelEditor), typeof(System.Web.UI.Design.WebControls.PanelContainerDesigner)). The child controls of this custom Panel Control at design time can see all the exposed properties that I want to share from the Parent (no problem here).
However, if I place controls on an UpdatePanel, these child controls cannot see the parent container but instead, it immediately sees the form/page or DesignerHost. The problem is the same even if I put Panel on the UpdatePanel and vise versa.
Is there a way to manage controls inside an update panel? For me, this behavior is like saying that UpdatePanel is not container based during design time?
I was referred here by MSDN forums hope this is the right place - I have a custom control (:WebControl) that renders web.sitemap in a specific way. While it runs error free and produces the expected result, at Design-Time it complains
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and have tried the SiteMapDataProvider Tag with and without the SiteMapProvider attribute.Does anybody have (a) any experience with this, or (b) any suggestions as to how to track down the problem?
I'm developing a custom server control and want it to end with /> rather than with </cc1:CustCtrl>. I've tried changing the ToolboxData but it didn't really do it (I can see it initially appears like that but instantly changes to the standard <cc1:CustCtrl blah blah></cc1:CustCtrl>. When i drag a button from the toolbox to the forms markup it uses the <asp:Button blah blah /> markup, how can I emulate this?
i create a custom control which can hold some templates, such as Header, Body Footer, etc.
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i tried to use smarttags to allow the user to edit each of the templates, which worked pretty well. what i could not get working was to add a template if it has not been in the control. eg. add a header-template to the control above. i tried using the RootDesigner.AddControlToDocument() function of my controldesigner. but this function gives me an error, telling me the control i'm going to add the template (i used a new HtmlGenericControl("HeaderTemplate") as new Control) to is not valid. (i can't give the exact error message, cause i use a german version of visual studio 2008) i've been searching the web for nearly half a day now, but i did'nt find a working solution for my problem.
I have created an advanced label control using web user control to cater some advanced options needed for my application. The control is working fine but there is one hitch bothering me. In normal label control when we change text or color, we can see effects during design time also but this is not functional with web user control. I mean when i change TEXT property of my label inside user control, the effect is visible on runtime not design time.
Is there any way to see effect of property changes during design time??
I have created a custom control from scratch and it works fine as in you can build the project that uses it and it works fine at runtime. Problem is when you go to design view the control shows an error in the place of where the control should be rendered.
Error: '<SomeValue>' Could not be set to '<SomeProperty>'
This shows up on all my custom set properties. These properties are created as basic as possible. I can give the properties values in Source view and run the app just fine. I can even add a Onclick event. If I don't set any custom properties the control will render fine in Design view. It's only when I set a value to a custom property.
Property Code Example:
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I've even removed the Category and Description tags with no difference.
I don't know if what I said makes sens, but I hope it does.
I seriously want to learn how to create a custom server control, for that I made a requirement for myself, but lost on how to accomplish it. Requirement -I want to create a cascading dropdownlist control - which should have following properties -1) ConnectionString - used to get data for the 1st dropdown from database, and also it is used by 2nd DropDown to get data.2) 1stSelectCommand - Used by the 1st DropDown to get data from the database.3) 2ndWhereCommand - used by the 2nd DropDown - uses the selected value from the 1st DropDown in the where clause to get data. Methods - 1) DropDown1_SelectedIndexChanged()2) DropDown2_SelectedIndexChanged(3) CustomCascading_Changed() - this happens when any of the DropDowns index changed. PS - This is a random requirement, of course it got nothing to do with any project or real time.I want to learn, so i incorporated basic concepts like Data Access, Custom Methods, Properties etc.PPS - I know how to create basic custom server control, so plz dont forward me links to how to create basic custom server controls. But in case with extrordinary links.
I have a simple HttpHandler that generates a dynamic image based on query string parameters and a custom web control that renders an image tag pointing to the handler as its 'src' attribute. All works fine when run in the web server, but at design timethe control displays as the "missing image" icon (red x in a box). The handler is registered in the web.config with a ".ashx" extension. The RenderContents method in the control looks like this:
I have a site using eight (so far) custom web user controls and two of them have started misbehaving in design view. When designing the control itself some (in one control) or all (in the other) regular controls (labels, text boxes, etc.) disappear from the design view surface. They can still be seen in the source view and if the control is hosted on a regular .aspx page the control displays properly. The code window recognizes all controls in the objects dropdown list and I can write appropriate code. The controls run properly on their hosted pages.
If I switch to Split view and select controls in the source view panel a very small area od the design surface becomes selected (like one pixel for any of us who remember programming old DOS applications with 80-column screens) but no controls can be seen.
In short, the controls work in every respect except that I cannot see all or part of the design surface in Design view when editing the controls directly.
I've double-tripple checked the source code for anything that may be causing this and just don't see anything. (The controls aren't that complicated.)
I'm developing a set of custom controls, one of them are the "parent", any others must be added inside an ITemplate property of this parent. But in the page, at design time, I can see, by intellisense, the other controls at page level, and I can theorically add them everywhere. I want to emulate the behaviour of the asp:Table and the asp:TableRow, you can't directly add an asp.
I created an Extender which has a custom property that drills down a list XML elements from an xml file, where users can select xml elements during design-time. This works perfectly fine. However, my code only has a hardcoded xml filename (source of the xml elements list) and I need to change this by maxing the xml file user-specified.
What I did is that I created another control (panel) which has a custom property that when clicked (through the ellipsis), it will allow a developer to select the xml file which is supposed to be the source xml file that the Extenders shall use. The filedialog from custom panel's property works perfectly fine.
However, my problem now is that when I drag-drop my Extender, I cannot find a way to get the property value of the custom Panel Control which contains the xml filename. I tried creating a static variable which I thought the custom controls can share but VS2010 is breaking.
I installed Rad Controls. Using that controls, I designed my application pages. At design time, the design is not visible. It shows the following error:
RadTabStrip1Failed to create designer 'Telerik.Web.UI.RadTabStrip, Telerik.Web.UI, Version=2010.1.415.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4'
The method GetDesignTimeHtml of the ControlDesigner class should return html markup that will be shown on the page in design time. My problem is that control looks different in different versions of the visual studio. What is the rendering engine visual studio use to render control in design mode?
I am rendering custom control. I rendered the css file on the prerender. When i rendered more than one control in the aspx page, the css will loaded the number of times the controls in the page. I want to load the css file only one time. How to check the webresource css file on rendering whether it is loaded or not.
I'm getting some wierd behaviour with my User control. I've created User control & it has BUTTON which checks the validity of the number entered in the textbox of that user control. I have written Button Clik event handler in the USer Control code behind which checks the database table and tells valid or not. So far so good. In my application i dynamically add User controls. I make sure that I add them Page_Load so that for every postback UCs are visible. I'm ussing Session to save my UserControls. The problem starts at some point when i click the Validate button in the User Control all my user controls dissappear & after some postbacks all my controls appear. I don't know why this is happening. I have included my code for reference.
I've just started working on some test asp.net webforms projects and am having a problem with VS2010. It is not displaying any controls at design-time. For every control I'm getting message -
Error Creating Control - xxxxx Object reference not set to an instance of an object
It is doing it on new web.application and Tailspin Spyworks demo app. If I switch a new web.app from asp.net4 to asp.net3.5, all the controls display properly.
I've tried removing and re-installing VS2010 and had no changes.
Am I right in assuming that only after controls on Master page are merged into the control tree for the Page, can controls ( both those in Master page and in a content Page ) be initialized with their declarative values ( values set during design time)? b) If my above assumption is correct, then these controls cannot be initialized with their design-time values during Page.PreInit, since during Page.PreInit event stage we're still able to dynamically set a Master page?! So if that is the case, when are controls initialized with their declarative values? During Init event orâ€
None of my user controls display on a web form at design time. At runtime they work fine and at design time to design the user controls themselve is fine.
Is there a setting that is telling the controls not to render at design time?
a) Assuming a page has a master page associated with it, then all controls (those declared in master page and those declared in content page) created during design time are assigned declarative values only during an Init event? I'm assuming this since to my understanding controls need first to be put into the control tree before they can be assigned their declarative values? And when page has a master page associated with it, then aren't page's controls put into the control tree only during the Pre_Init or perhaps even during the Init event? Then if that is the case, then isn't the earliest that these controls can be assigned their declarative values during Init event?
b) Assuming our page is associated with Master page and also uses a theme --> skin files are also applied during an Init event, so I assume that during an Init event Asp.Net first initializes controls to their declarative values and only then applies skin rules to them?
