I'm working with referencing user controls on my ASPX page and I'm wondering what the difference is between these two page directives.
#Reference
#Register
#Register is primarily used for registering tag prefixes to declaratively use controls within a page.
<%# Register tagprefix="my" namespace="MyNamespace" %>
<my:CustomControl runat=server />
#Reference is primarily used to refer to a page or user control (by file name or virtual path) to programatically refer to members of the page or control.
<%# Reference Control="MyControl.ascx" %>
<% MyControl ctrl = (MyControl) Page.LoadControl("MyControl.ascx");
ctrl.CustomProperty = "..."; //REFERENCE directive is needed to access property
%>
#Register is the more commonly used directive. You use this when you want to use a user control in your aspx or ascx page declaratively. #Register associates the control with a specific prefix and you can then use it in your markup.
#Reference only tells ASP.NET to compile the other control when your aspx or ascx page is compiled. That makes sure it is available at run-time and can be added to your control hierarchy programmatically. This is less common since dynamically changing user controls at runtime is not comon.
Here's a good blog post about it.
http://weblogs.asp.net/johnkatsiotis/archive/2008/08/13/the-reference-directive.aspx
Related
Hi I'm using in my application with ASP.NET WebForms and VB.NET (code behind) the ajaxcontroltoolkit so, i need use enable a page method but if I add
< asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="True" EnablePageMethods="True" > < /asp:ScriptManager >
to the code this mark error:
You can only add one instance of ScriptManager to the page.
My question is in ajaxcontroltoolkit exist a function equal to EnablePageMethods of ScriptManager?
It may likely that you would have definitely added a ScriptManager somewhere else in your .aspx Page or MasterPage or UserControl.
If you have declared a ScriptManager on your Master page, then in your content pages you would use a ScriptManagerProxy. This will act as a proxy to the real ScriptManager on your master page.
Here is the MSDN link that describes about ScriptManagerProxy
Only one instance of the ScriptManager control can be added to the page. The page can include the control directly, or indirectly inside a nested component such as a user control, content page for a master page, or nested master page. If a page already contains a ScriptManager control, but a nested or parent component needs additional features of the ScriptManager control, the component can include a ScriptManagerProxy control. For example, the ScriptManagerProxy control enables you to add scripts and services that are specific to nested components.
Ensure that you have only one asp:Scriptmanager on the
masterpage.
If you don't need a asp:Scriptmanager in materpage then remove it and declare it in content pages whichever needs it.
If you have a ScriptManager in masterpage then make sure you also have only one
asp:ScriptManagerProxy on every content page that might require a script manager.
I need to access multiple textboxes on a master page. The textboxes are declared in a separate web control and it won't let me call the names of the textboxes so I can populate them with data. I have multiple textboxes like I said, but for example, when I try to write to txtName it will not let me even though when I click on the Design View it says it is there.
Can anybody help me out?
Expose the text boxes inside the web control as properties.
In webcontrol.ascx
<asp:TextBox runat="server" id="txtName" />
In webcontrol.ascx.cs
public virtual TextBox TxtName { get {return txtName;} //note capitalization
Then do the same thing in the master page to expose the web control.
In masterpage.master
<uc1:MyWebControl runat="server" id="MyWebControl1" />
In mastermage.master.cs
public virtual MyWebControl myWebControl{get {return myWebControl1;}}
Then make your master page strongly typed from the content page by adding a MasterType directive.
In default.aspx
<%# MasterType TypeName="MyMasterPageClass" />
Then you can access it from your content page code behind. In default.aspx.cs
Master.myWebControl.TxtName.Text="Hello, world!";
The reason it's necessary to do this is that controls declared on .aspx, .ascx, and .master pages are protected instead of public and there's no way (as of right now) to change them that I'm aware of. So we can use properties to expose these controls as public.
Can anyone tell me if I can dynamically set the file name when registering a user control please, for example:
<%# Register src="[file name]" tagname="WebUserControl" tagprefix="uc1" %>
No, I don't believe you can. What you can do is register all of the possible controls that you might use on the page, either in the page directive or the web.config.
EDIT
What you can do, if this helps, is to add the controls dynamically in code-behind using the LoadControl method. This way, you can create instances of whatever user controls you want without worrying about registering them in the page directive or web.config. Thanks #Gabriel for pointing this out.
I have a UserControl that I need to add dynamically. I tried to follow this MSDN article, but I'm not having any success....
http://msdn.microsoft.com/en-us/library/c0az2h86.aspx
The UserControl is basically an image gallery, and it loads some pictures based on an ID. My idea was to make this ID available as a property. Then when I create an instance of the control, I could set this ID and add it to the form.
I added a reference to the control in the .aspx page that will use it, like this:
<%# Reference Control="~/PictureGallery.ascx" %>
And in the UserControl I added a ClassName like this:
<%# Control Language="C#" AutoEventWireup="true" CodeFile="PictureGallery.ascx.cs"
Inherits="PictureGallery" ClassName="PictureGallery" %>
When I try to create an instance in the .aspx.cs like the article suggests, Dim gallery As ASP.PictureGallery, I get an "Type ASP.PictureGallery is not defined".
The article mentions a namespace, ASP, and I tried importing it to the .aspx.cs with no luck.
So, I'm not able to get a reference to the UserControl.
How can it be fixed?
It sounds like you are confusing two separate ways of working with a UserControl.
One way is to register the control on your page so that you can put it into the page at Design Time e.g.
<div>
<asp:PictureGallery id="myGallery" runat="server" MyProperty="SomeValue">
</asp:PictureGallery>
</div>
The second is programmatically (or dynamically) adding it into the page at runtime in your code behind. If so, then you need to use the LoadControl function which is mentioned in the sample. You do not need to register the control in the aspx file if you do this.
e.g.
Dim gallery as PictureGallery = LoadControl("~/PathToControl/gallery.ascx")
gallery.MyProperty = "SomeValue"
placeHolder.controls.add(gallery)
edit
What is the class name of the control in the code behind...something like this:
Partial Public Class MyControlsClassName
Inherits System.Web.UI.UserControl
That is the type you need to use when you declare it. Is it within a namespace perhaps?
I don't think you've placed the control in your code behind. You may well have created the reference, but do you have a tag such as <asp:PictureGalary id="gallary"></asp:PictureGalary> anywhere in your aspx?
The ASP namespace is generated at run time- user controls get "compiled" as they are used by .aspx pages so this is why you get the error message "Type ASP.PictureGallery is not defined".
When adding user controls dynamically you should use the Page.LoadControl method:
Page.LoadControl("~/PictureGallery.ascx")
I'm trying to load User Control from another project, And I like to do it with it's name space:
<%# Register TagPrefix="IPGostar" Namespace="IPGostarPorject" Assembly="IPGostarPorject" %>
but this way when I use this server tag:
<IPGostar:DataGrid runat="server" ID="DataGrid1"></IPGostar:DataGrid>
the Page_Load of the DataGrid.ascx.cs will load but the content of ascx file won't load.
It's like this tag only calls the cs file and not the ascx file at the first place..
In this case, is it okay to load a .ascx user control file inside a cs file? (for example on Page_Load function we render the ascx file) and if it is okay how can I do that?
Second am I on the wrong path here?
Modfiy register tag to something like
<%# Register TagPrefix="IPGostar" TagName="IPGostar" Src="DataGrid.ascx" %>
If you are using a user control you have to specfiy the Source file. Your syntax holds good for custom controls.
You need to look into loading the control using Page.LoadControl().
At runtime, the ascx inherits from the class defined in the ascx.cs. They are not the same thing. The control defined in the ascx is a subclass of that in the ascx.cs.
If you want to distribute a control entirely as a binary, you will need to rewrite it as a ServerControl rather than a UserControl with an ascx.
You can't render the ASCX from the Page_Load of the class in the code behind. That won't work how you are thinking it might.