I found a few ways around this.

If you know the object type you're going to be using you can bind the WDG to an empty list of said object. Tack on an ID field and you can use some of the AutoCrud things. As long as you don't try to save the list to session state or something crazy like that.

An example to follow:

public class exampleClass

{

public string foo {get; set;}

public string bar {get; set;}

public int ID {get; private set}

}

In your code behind:

protected void Page_Load(object sender, EventArgs e)

{

List<exampleClass> test = new List<exampleClass>();

SomeWebDataGrid.DataSource =  test;

SomeWebDataGrid.DataBind();

}

You can add things in client side java script like this:

function addToGrid()

{

var grid =  $find("<% SomeWebDataGrid.ClientID %>";

var rows = grid.get_rows();

var ID =  Math.floor(Math.Random() *100001);  //Can be whatever you want as long as its unique

var foo = "test1";

var bar = "test2";

var newRow =  [ID, foo,bar]; //must be in order of columns

rows.add(newRow);

}

Hope this helps.