Best way to access properties of my code behind class from the markup in ASP.NET

Question

Let's say I have two files default.aspx and the associated default.aspx.cs.

default.aspx.cs:

protected void Page_Load(object sender, EventArgs e)
{
    var myObject = new MyObject();
}

Is there a way that in the default.aspx I could do something like:

<%= myObject.SomePropertyOfThisObject%>

... or something similar, without having to use databinders or something complicated like this? And if there's no way around binding the data, what would be the best way to do it?

Answer 1

You can, but you'll have to do it a bit differently. In your default.aspx.cs, add a member:

protected MyObject _myObject;

Then, in Page_Load:

protected void Page_Load(object sender, EventArgs e)
{
         _myObject = new MyObject();
}

Then, in default.aspx, you can do:

<%= _myObject.SomePropertyOfThisObject %>

Of course, this assumes that class MyObject has a property named Awesome. You didn't mean the System.Object class, did you, since it doesn't have a property named Awesome.

---

Since your question was asking about the best way, I'll go further. The way I showed is not the best. The best is more often to use a data binding expression. If you don't like those, then you can set things in the codebehind:

protected void Page_Load(object sender, EventArgs e)
{
         _myObject = new MyObject();
        //
        _myLabel.Text = _myObject.SomePropertyOfThisObject;
}

Assuming:

<asp:Label runat="server" id="_myLabel" />

Answer 2

The <%= ... %> is ASPX short-hand for Response.Write( .... ).

If you change myObject to be strongly types (rather than just types as Object) you can certain use the line:

<%= myObject.Awesome %>

to emit a value.

Be aware, however, that the <%= syntax has limitations - specifically:

• it cannot be used within HTML attribute as a value
• it cannot emit server-side elements
• it cannot be used within ASP UpdatePanels - you will get a exception when you perform a partial postback

You are probably better off creating a Label control on you page, and programmatically setting the Text property to the value. This also gives you more control over how value-to-string conversions are performed. And will work correctly with update panel controls.