Creating webpages with Excel Web App mashups

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Unfortunately the functionality discussed in this article is no longer available

Getting input from web form controls into your Excel file

Wouldn't it be nice to have a web form which users can enter data into and have your Excel Web App updated with the content of the web form. That is what I describe here.

Put up a form with some controls

To get data from a form textbox into your Excel file, you need to place a form on your web page. This piece of html does that:

<form name="ChangeInput">
    Phase difference (degrees) 
    <input name="Phase" size="18" style="width: 112px" />
    Frequency ratio 
    <input name="Freq" size="18" style="width: 112px" />
    <input onclick="JavaScript:SetValuesInSheet();" type="button" value="Update Chart" />
</form>

As you can see, the button's click event is set to call a Javascript function called SetValuesInSheet.

Writing values in a cell

The SetValuesInSheet function is relatively short:

function SetValuesInSheet()
    {
    // Get a reference to where we need to write
    ewaCht.getActiveWorkbook().getRangeA1Async('b1:b2', getRangeA1Callback, null);
    }

As you can see, we first need to ask the Ewa to give us a reference to range B1:B2 in the active sheet. This is done asynchronously, so a call-back function is needed: getRangeA1Callback. Listed below:

function getRangeA1Callback(asyncResult)
        {
        // getRangeA1Async returns a range object through the AsyncResult object.
        var range = asyncResult.getReturnValue();
        var values = new Array(2);
        values[0] = new Array(1);
        values[1] = new Array(1);
        var control = document.ChangeInput.Phase;
        values[0][0] = control.value;
        control = document.ChangeInput.Freq;
        values[1][0] = control.value;
        // Now send the array to the range.
        range.setValuesAsync(values,Dummy,null);
}

If you want to push data into cells, you always need to use an array, like the code above shows.

Because the setValuesAsync is -again- asynchronous, it requires a callback, for which I included an empty function called Dummy (not shown here). NB: Dummy can be replaced with "null", but I left it in because the code works as it is.

So does this all work? Have a look at the next page!