Question

I am calling an ASP.NET Ajax method (e.g. a method tagged with [Ajax.AjaxMethod]) on a control which is dynamically created in JavaScript when the user clicks a link (basically it is inside a table, and when the link is clicked a tr/td is built out in JS code and added to the table). In the callback function I need to know what row is being called since I’m appending data to an input control in that row only; I have a hidden field that contains the total number of items added, but I cannot use this as it always adds to the last row (since it is incremented when a new row is added) not the row which is firing the function.

Something like the following:

// fieldName is a lookup string...
function loadOperators(fieldName) { 
    MyPage.LoadOperatorsFor(fieldName, loadOperators_Callback);
}

function loadOperators_Callback(response) { 
    var currentRow = // how to obtain this?

    // do other stuff here...
} 

I am also using jQuery but the methods are done in ASP.NET AJAX style as that’s the current style we use at work.

How am I able to determine the actual row which is firing the Ajax function, so I only populate the dropdown list contained in that row (I cannot rely on the user creating a row, and then populating that row; they might create say 5 rows and then go back to Row #2 and select something, so I would have to know they chose a value in Row #2 and not 3/4/5)? It doesn’t seem to be part of the response object, but the Callback function doesn’t seem to take any additional parameters.

The only thing I can think of doing would be to add it to my AjaxMethod so it would be passed back in the response, but this seems like a hack at best since I return a DataSet and the row number has no bearing on the data.

I forgot to add, I am not using the ASP.NET AJAX library, only jQuery and tagging methods with [Ajax.AjaxMethod]

Answer 1

For the record I was able to solve this by simply using an inline anonymous function so I can reference the lineNumber from the calling method, instead of passing a function reference. Simply and effective.