i have this aspx code that used to work (on .net 2.0):
<Templates>
<EditForm>
<div>
<dxe:ASPxMemo runat="server" ID="Memo1" Text='<%#Bind("field1")%>' Width="100%" Height="60px" ReadOnly="true" BackColor="#E6E6E6"></dxe:ASPxMemo>
...
Now i'm trying to re-use it in the same context but using .net 3.5, but i got an error. I'll try to translate it:
Can't edit Controls because the control contains blocks of code (like
<% ... %>).
so i tried to do via vb.net code this:
Memo1.Text = #Bind("field1")
but looks like a can't access Memo1 because of protection level
how i can make this work again?
edit: found a tutorial here http://demos.devexpress.com/aspxgridviewdemos/GridEditing/EditFormTemplate.aspx
but the tutorial uses bracket insde Text too!
Solved!
Looks like that ASPxGridView doesn't like <% ... %> code inside the page header.
Some days ago i added in my master page's <head> a simple <% Response.Write() %> and the entire ASPxGridView failed because of that.
Moving that code outside the header resulted in a working ASPxGridView, that was not a problem of .NET framework version!
Related
I have an ASP.NET 2.0 web application, and on one of the pages I have a div defined like this:
<asp:Panel runat="server" ID="pnlAddJobCode" Visible="false" ClientIDMode="Static">
and it's inside of a content placeholder defined like this:
<asp:Content ID="Content3" ContentPlaceHolderID="MainBodyContent" runat="server">
but when the HTML is generated I get a name like this ctl00_MainBodyContent_pnlAddJobCode so clearly it's not honoring the ClientIDMode. The problem is I need to set some styles on this specific div -how can I get the ClientIDMode to work here?
Does ClientIDMode not work in ASP.NET 2.0? I have found a few articles on Google that elude to it not working, but nothing concrete.
Client ID Mode is new in ASP.NET 4.0. There's more information about it in the breaking changes for ASP.NET v4.0.
I am a asp .net beginner. I want to use some objects created at Site.Master.cs in Site.Master. Is there an easy way to do it?
I know how to do it in MVC(by using view(the object)). But how can i do it in normal ASP .net web application?
I don't understand what exactly you want to do.
If you want to insert some string into tag's title you can insert the following thing in SiteMaster.master file:
<img src="<%= Page.ResolveUrl("~/") %>images/logo.png">
instead of:
<img src="images/logo.png">
In the first case there will be calculated the path from the root of your application. In the second case there will be relative link. This is because server will CALCULATE the value of Page.ResolveUrl("~") function and will WRITE it in src tag.
You can do the same thing with any other methods, classes if you defined them properly. But I wouldn't recommend you to implement complicated logic in .aspx files (or .master files). Because you can end up with many difficulties with testing and styling such application.
There are other server tags:
<% %> - an embedded code block is server code that executes during the page's render phase. The code in the block can execute programming statements and call functions in the current page class. Description and examples
<%= %> - most useful for displaying single pieces of information. Description and examples
<%# %> - data binding expression syntax. Description and examples
<%$ %> - ASP.NET Expression. Description and examples
<%# %> - Directive Syntax. Description and examples
<%-- --%> - Server-Side Comments. Description and examples
<%: %> like <%= %> - But HtmlEncodes the output (new with Asp.Net 4). Description and examples
Another way: you can use JSON to send some data to the client and then process it with javascript. Take a look at this project.
If the #Page directive in your .aspx file has Inherits="XYZ" where XYZ is the class declared in your .cs file, you can simply add a protected field to your class and assign a value to it. You'll be able to access it in the .aspx file just by using its name.
You can also use HttpContext.Items property to keep objects during a single request:
HttpContext.Current.Items["SavedItem"] = "hello world";
And use it in page:
<%= ((string)Context.Items["SavedItem"]) %>
Any public or protected property or method in Site.Master.cs will be accessible from Site.Master.
but how to invoke c# code in aspx ?
There are several ways, including the <%= %> construction, and databinding syntax.
It would help if you explained what you're trying to achieve.
I'm outputting a few lines of Javascript within a Repeater control on an ASPX page. I want to use a value from my DataSource inside the script tag.
A very basic example might be:
<asp:Repeater ID="RepeaterBlah" runat="server">
<ItemTemplate>
Hello <%# DataBinder.Eval(Container.DataItem, "SomeName")%>
<script>myfunction(<%# DataBinder.Eval(Container.DataItem, "SomeNumber")%>)</script>
</ItemTemplate>
</asp:Repeater>
I'm aware that most people won't repeat script tags like this, but I am using a small snippet of code from a third-party that you can place anywhere on a page to create a Flash object. You pass it a number so it knows which image gallery to display. No problems using several on one page.
To begin with, this worked fine, although I noticed the colours in Visual Web Developer indicated that it didn't really like the <%# being used inside a <script> tag. Intellisense was going a bit nuts in the code-behind too!
So what is the correct way to pass Dataset items into a script tag?
This perhaps? (Can't quite remember if the + signs should in fact be & signs though)
<%# "<script>myfunction(" + DataBinder.Eval(Container.DataItem, "SomeNumber") + ")</script>" %>
Another alternative syntax would be the following:
<%# Eval("SomeNumber", "<script>myfunction({0});</script>") %>
This uses the optional parameter where you can supply a format string.
What are the differences in these tags?
<%
<%#
<%=
<%$
More importantly, how do I display a page property using declarative syntax in an ASP.NET control? I'm trying to do this in an ASP.NET control. The task is to set the text of a label but I do not want to do this pro grammatically in the event I want to change the output control. I get an error about server side controls can't contain this syntax. I'm not sure that I need a databound control for what I want to do but that is another option.
Partial answer coming up.
Update
There is a new tag I've seen in ASP.NET 4.5? site
<%:
Partial answer
quoted from Mike Banavige
<% %> An embedded code block is
server code that executes during the
page's render phase. The code in the
block can execute programming
statements and call functions in the
current page class.
http://msdn2.microsoft.com/en-gb/library/ms178135(vs.80).aspx
<%= %> most useful for displaying
single pieces of information.
http://msdn2.microsoft.com/en-us/library/6dwsdcf5(VS.71).aspx
<%# %> Data Binding Expression Syntax.
http://msdn2.microsoft.com/en-us/library/bda9bbfx.aspx
<%$ %> ASP.NET Expression.
http://msdn2.microsoft.com/en-us/library/d5bd1tad.aspx
<%# %> Directive Syntax.
http://msdn2.microsoft.com/en-us/library/xz702w3e(VS.80).aspx
<%-- --%> Server-Side Comments.
http://msdn2.microsoft.com/en-US/library/4acf8afk.aspx
Update:
Okay this appears to work
<asp:Label ID="MyLabel" runat="server" Text='<%# MyProperty%>'></asp:Label>
If I use the eval syntax then I get an error about databound control or I use the <% then I get a server side controls error. Any more color appreciated.. not sure I really understand what is going on.
Perhaps it has something to do with the render phase.
Few more observations:
I can use <%= without databinding and get the property value but can not use it in a server side control without getting error.
If I use <%# in server side control but I'm required to do a Page.Databind.
Interestingly, I can use either <%= or <%# when I want to render text that is not inside a control. Although the latter requires databinding.
The new <%: syntax is explained, also called code expression syntax
With ASP.NET 4 we are introducing a new code expression syntax (<%:
%>) that renders output like <%= %> blocks do – but which also
automatically HTML encodes it before doing so.
http://weblogs.asp.net/scottgu/new-lt-gt-syntax-for-html-encoding-output-in-asp-net-4-and-asp-net-mvc-2
No, server-side controls can't. For example, I have a string property named SkinPath that give me the full App_Themes path to the current theme. I use it in the following way:
<img src='<%= SkinPath %>/Images/myImage.png' />
However, the following doesn't work:
<asp:Image ID='image' runat='server' ImageUrl='<%= SkinPath %>/Images/myImage.png' />
Instead, it renders the src literally in the result <img>.
I have some code in my master page that sets up a a hyperlink with some context sensitive information
<%If Not IsNothing(Profile.ClientID) Then%>
<span class="menu-nav">
<a target="_blank"
href=
"http://b/x.aspx?ClientID=<%=Profile.ClientID.ToString()%>&Initials=<%=Session("Initials")%>"
>
Send
<br />
SMS
<br />
</a>
</span>
<%End If %>
<span class="menu-nav"> <!-- Name __o is not declared Error is flagged here-->
Now the issue seems to be in the href part. If I remove the dynamic code the error disappears. Can anyone tell me how to resolve this issue?
I've found the answer on the .net forums. It contains a good explanation of why ASP.Net is acting the way it is:
We have finally obtained reliable repro and identified the underlying issue. A trivial repro looks like this:
<% if (true) { %>
<%=1%>
<% } %>
<%=2%>
In order to provide intellisense in <%= %> blocks at design time, ASP.NET generates assignment to a temporary __o variable and language (VB or C#) then provide the intellisense for the variable. That is done when page compiler sees the first <%= ... %> block. But here, the block is inside the if, so after the if closes, the variable goes out of scope. We end up generating something like this:
if (true) {
object #__o;
#__o = 1;
}
#__o = 2;
The workaround is to add a dummy expression early in the page. E.g. <%="" %>. This will not render anything, and it will make sure that __o is declared top level in the Render method, before any potential ‘if’ (or other scoping) statement.
An alternative solution is to simply use
<% response.write(var) %>
instead of
<%= var %>
Yes, I have experienced the same bug occasionally in pages that use server side constructs on ASPX pages.
Overtime, I found a fix for it (I'm sorry, I just haven't been able to find out where I found this bit of info again.) and that fix is to put the following code above the errant <%...%> block:
<%-- For other devs: Do not remove below line. --%>
<%="" %>
<%-- For other devs: Do not remove above line. --%>
Apparently, where you put the above code makes all the difference to VS.NET, so it may take a few tries to get it right.
This is an odd solution, but for me I managed to fix this problem by simply closing the offending open files in Visual Studio.
With them open, i was erratically getting the __o problem.
As soon as I closed them, the __o problem disappeared.
After some hours of googling and analyzing bunch of aspx'ses in my current project seems I've found the solution, that is working for me. Would to advise strongly avoid html-style comments:
<!-- ... -->
inside aspx page. Instead of it use aspx-style comments
<%-- ... --%>
Additionally it helped me obtain that vs intellisense and code highlighting became working again and the mainly thing - this case had begun from it - vs can now hit the breakpoints inside embedded pieces of vb/cs code! And no any damn "This is not a valid location for a breakpoint" message.
When I've cleaned the solution, restarted IIS and it is still mysteriously playing up, I find this can sometimes be caused by pasting an ASPX source file's contents from another system into Visual Studio which "helpfully" updates the code, possibly changing some IDs and breaking the page.
Pasting it into another editor (Notepad++?) then saving it stops Visual Studio from "being helpful" and the page works again.