I have a content page which has a related master page.
I register a prefix <%# TagPrefix ..... and can load other custom controls at that namespace.
However, one particualar control at the same namespace, when added to the aspx page, breaks it.
The control in question inherits from asp:Panel, has a parameterless constructor, defines a few public accessors, and creates some standard child controls, and nothing much else.
Are there some fundamental restrictions to creating custom asp controls that I am breaking unknowingly?
Add the control back to the page. Delete the designer file for the page: .aspx.designer.cs
Then right click on the page and select Convert to Web Application. This should give you the actual error the page has when attempting to write the control definition to your designer file.
I suspect there is a compilation error in your custom control.
My control was attempting to access Page.Header which was null as the master page had not marked the tag with runat="server".
I guess that is a fundamental restriction that I was looking for...
Related
I am very new to asp.net and my job.
I was assigned a project to make a simple online order web application using asp.net c#.
The specification has been strictly defined (copied below)
Regarding the common content of the site, I need to make head, top and left(a search function)
"The design in /design/: Head.aspx Top.aspx Left.aspx"
-- Does that mean I am not allowed to use (nested) master page?
--- If so, how can I make a template without using master page?
Another option is to use the Server.Execute() method to render the contents of three separate pages into your base page if you have to use pages instead of usercontrols and still must have three separate pages rendered into one.
In the old days we did this with iis html includes.
If the head/top/left content is just basic HTML, then you could just put the HTML in a separate file and use an include link/reference in the original .aspx page.
If the content is all like a search function, then I agree with Henk's comment, create an .ascx User Control (which is really no different than an .aspx page with an .ascx extension) and then just reference that control on your .aspx page like this:
//put this at the top of your .aspx page
<%# Register src="usercontrols/YourControl.ascx" tagname="nameOfControl" tagprefix="ucControlName" %>
//then reference your control where you want it in your .aspx page
<ucControlName:nameOfControl ID="nameOfControl" runat="server" Visible="True" />
Here's an MSDN article on creating user controls: MSDN User Control
Maybe shoot the person who wrote the spec an email and ask why they have an issue with using a master page - this is kind of exactly why you would use one?!
JM
I have an asp.net Application i have added some .aspx pages in the root directory.. now i have created folder named usercontrols having following structure :
now i want to call a Method of one user control into another.. but i dont get the class name of any user controls in between..
i have used same namespace in all .ascx.cs file..
so how to call a Method of one user control into another ??
Thanks
You need a reference declaration to use the uc within your code:
Add it to your page:
<%# Reference Control ="~/WebUserControl1.ascx"%>
I have a Web Site project, and within it I have a user Web Control defined in an ascx file.
The control is added to the Site.Master, and it shows up correctly on the page and everything is fine.
I need to override some of the control's fields on one of the pages that derive from Site.Master.
// In OnLoad:
MyControlName control = (MyControlName) Page.Master.GetBaseMasterPage().FindControl("controlID"));
The issue is that MyControlName doesn't register as a valid Type on the child page. If I add a second instance of the control to the child page directly, the above works as needed, but if the control isn't placed directly on the page, and instead is only defined in the master page, the type is undefined. The control is not in a namespace, and is defined within the project, so I don't know why it is having such an issue location the appropriate type.
If I put a breakpoint in the OnLoad, the type listed for the control is ASP.my_control_name_ascx, but using that does not work either.
Why can't the child class reference the correct type? Can I fix this?
Thanks!
The control does not have global scope over the entire project. It will only be selectable as a type on pages where the control is registered. So you have to register the control on the child page:
<%# Register src="WebUserControl.ascx" tagname="WebUserControl" tagprefix="uc1" %>
You will need to add a register tag like above to the top of your child aspx page.
The other option is you could create an interface for the control which exposes the properties or methods you want to access, and put the interface in app_code or some other globally accessible place, then have the control implement the interface, and cast the control to the interface.
The following code works for me:
DropDownList ddlLanguage = (DropDownList)Page.Master.FindControl("ddlLanguage");
I take it GetBaseMasterPage() is your own method? What happens if you try:
MyControlName control = (MyControlName)Page.Master.FindControl("controlId");
?
Not a direct answer to your question, but you might find the #MasterType directive useful.
If you add a line like
<%# MasterType TypeName="ClientName.SiteName.MasterPages.SiteMaster" %>
to the top of your ASPX page, you should be able to refer to the master page in code without having to cast it. This might make it easier for the code to find your control, perhaps?
You could end up with a line like:
// In Page.OnLoad:
MyControlName control = Page.Master.MyControl;
and then expose a new property in your master page that wraps the FindControl call:
// In Site.master.cs
internal MyControlName MyControl
{
get { this.FindControl("controlID"); }
}
Hope this helps!
Basically, I have created a custom control that uses an UpdatePanel, and as I understand it I need to use a ScriptManagerProxy to make it work ( since there should only be one ScriptManager per page, and is is declared in my .aspx page ).So, how do you use this beastie, is it just a matter of adding:
<asp:ScriptManagerProxy ID="ScriptManagerProxy3" runat="server">
</asp:ScriptManagerProxy>
to your control, or is there more to it?
Could anyone please post a link to a good tutorial/example set? I tried googling for this, but I didn't find anything useful...
Your control does not require a ScriptManagerProxy to work. You would only need a ScriptManagerProxy if you needed to add a ServiceReference or ScriptReference in your control. The ScriptManagerProxy allows you to do this without having to have knowledge about the page that is going to host your control. When the page is rendered, the properties of the ScriptManagerProxy controls are merged with those of the ScriptManager control on the host page.
i have an admin master page where i want to place a label which i can control with two functions (setErrorMessage and setSuccessMessage) both functions assign strings to label's text property and change CssClass property according to function type.
I want to use these functions from nested pages while the control remains centralized on master page so i can return to form in case of error so user could edit wrong input.
How would you suggest me to do that ? either VB or C#
thanks
You can use below in .aspx
<%# MasterType VirtualPath="~/MasterPages/Default.master" %>
and below in your code behind,
this.Master.yourMethod
this.Master.yourProperty
to access your controls in child page.
you must convert type of Master property in nested page:
((MyMasterPage)this.Master).lblMessage.Text = "Hi.";