What is the standard ASP.net data binding syntax?

Question

Microsoft's introduction to data-binding using the asp:Repeater control gives the syntax to fetch a value:

<b><%# DataBinder.Eval(Container.DataItem, "orderid") %></b>

This syntax is repeated on other introductions to the ASP.net Repeater control:

<a href="<%# DataBinder.Eval(Container.DataItem, "URL") %>">...</a>

But i remember this syntax being "bad" and "wrong". From the MSDN documentation of DataBinder.Eval i see:

Note

Because this method performs late-bound evaluation, using reflection at run time, it can cause performance to noticeably slow compared to standard ASP.NET data-binding syntax.

(emphases added)

So that explains why i had a memory of "Eval is bad". But what is the "standard ASP.NET data-binding syntax"?

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Data-Binding Expression Syntax

score 3 · Accepted Answer · answered May 14 '12 at 18:15

I think you can just do a cast to avoid the "late binding" penalty:

<%# (((System.Data.DataRowView)Container.DataItem)["URL"]) %>

Now let's say you increase performance by x%. Is it worth it to your application? The trade-off (in my opinion) is less readability.

score 1 · Answer 2 · answered May 14 '12 at 18:41

1

Well "standard ASP.NET data-binding" generally refers to binding data from a data source to named controls, such as the textboxes on a form, or the old GridView where you can bind an entire table.

If you just need a read only display of data, you might consider a foreach loop or a DataReader to parse the data into raw HTML in a stringBuilder and then dump the StringBuilder into a Literal.

answered May 14 '12 at 18:41

KennyZ

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i was doing that (building the html i want). But then it was suggested that i make it "better", using nested repeaters to get something *close* to the html i want. Which is why i had to ask about binding syntaxes. – Ian Boyd May 15 '12 at 12:32

score 0 · Answer 3 · answered May 14 '12 at 18:47

This MSDN page describes standard databinding syntax as follows:

In the following code fragment, for example, an integer is displayed as a currency string. With the standard ASP.NET data-binding syntax, you must first cast the type of the data row in order to retrieve the data field, IntegerValue. Next, this is passed as an argument to the String.Format method:
<%# String.Format("{0:c}", ((DataRowView)Container.DataItem)["IntegerValue"]) %> 

What is the standard ASP.net data binding syntax?

Bonus Reading

3 Answers3