Inline coding in ASP.NET page

Question

hi guys i am using this code in my aspx page

<%for (int i=o;i<5;i++)
{%>
  <asp: link button id=i text=i/>

<%}%>

at it's producing five link buttons like

i i i i i

but i just want five link buttons like that

1 2 3 4 5

with id=1,2,3,4,5 respectively

how can I can implement that

Answer 1

This isn't exactly the best way to do things in ASP.Net. Dynamic controls have many gotchas, and you just found one of them. This code is a little better (make sure the page calls DataBind() at some point):

<%for (int i=0;i<5;i++)
{%>
  <asp:LinkButton id="<%# i%>" runat="server" text="<%#i%>" />

<%}%>

but you'll find that events and changes don't wire up the way you'd expect them to, if it works at all. With only five of them, it's better to just list them out by hand, and things will be much easier down the road. Or, if they came from a datasource somewhere use a repeater and create them that way.

Really, you don't want to mix code into your aspx markup at all if you can help it. Leave it for the code behind!

Answer 2

YOu need to actually print out the value of I on the server side.

<%for (int i=o;i<5;i++) {%> 
    <ASP:LinkButton Id="<%=i%>" Text="<%=i %>" />
<%}%>

Answer 3

Put a placeholder in the page where you want the links:

<asp:PlaceHolder ID="LinkContainer" runat="server" />

In the Page_Load method in code behind, you put the links in the placeholder:

for (int i = 1; i <= 5; i++) {
   LinkButton link = new LinkButton();
   link.ID = "Link" + i.ToString();
   link.Text = i.ToString();
   LinkContainer.Controls.Add(link);
}

This way the controls will be created early in the page cycle, and it's possible to hook up server side events to them if you like.

(Note that I added a prefix to the id. Having an id that is only digits can cause problems in some situations.)

Answer 4

You need to be careful how you actually render this. Note that HTML ids that start with a number are illegal according to the specification. I would prepend some alphabetic character to the id value to be sure that it is both legal HTML and that the control id generated is legal for ASP.NET. It's unclear to me whether it's legal or not to use just a numeric value for a control id. Note that ASP.NET control id characters must be alphanumeric or an underscore.

HTML Reference:

ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

ASP.NET Reference

Note: Only combinations of alphanumeric characters and the underscore character ( _ ) are valid values for this property. Including spaces or other invalid characters will cause an ASP.NET page parser error.