var serviceObj = null;
 
// Contains current export or import transaction id value 
var currentTransactionId = 0;
 
window.onload = init;
 
// Initializes the widget
function init() {
    // Obtain the service object
    try {
        serviceObj = device.getServiceObject("Service.Calendar",
            "IDataSource");
    } catch (ex) {
        alert("Service object cannot be found.");
        return;
    }
}
 
function showEntries() {
    // Showing entries is omitted here for brevity. Refer to the See also
    // section of the code snippet for more information.
    // ...
}
 
/**
 * Imports all entries from the specified file to the calendar.
 */
function importEntry() {
    var criteria = new Object();
    criteria.Type = "CalendarEntry";
    criteria.Data = new Object();
 
    // Name of the file from which calendar events will be imported
    var fileName = "C:\\Data\\Others" + document.getElementById("file").value;
    criteria.Data.FileName = fileName;
    // Get format of the file.
    if (document.getElementById("iCal").checked) {
        criteria.Data.Format = "ICal";
    } else {
        criteria.Data.Format = "VCal";
    }
 
    // Import the data
    try {
        var result = serviceObj.IDataSource.Import(criteria, importCallback);
        // Store current transaction id to global variable
        currentTransactionId = result.TransactionID;
        document.getElementById("state").innerHTML = "Importing...";
    } catch (ex) {
        alert("Error in importing entries: " + ex);
    }
}
 
/**
 * Callback function for import asynchronous call.
 * @param transId A number representing the transaction that called the
 * callback handler.
 * @param eventCode A number representing the callback return status.
 * @param result An object for holding the callback return value
 */
function importCallback(transId, eventCode, result) {
    // Check result of importing
    if (result.ErrorCode != 0) {
        alert("Error in importing: " + result.ErrorMessage);
    } else {
        alert("Data was imported successfully!");
    }
 
    document.getElementById("state").innerHTML = "";
    showEntries();
}
 
/**
 * Exports the selected entries from calendar to file.
 */
function exportEntry() {
    // Get the name of the selected entry
    var entriesList = document.getElementById("entriesList");
    var entryList = new Array();
    for (var i = 0; i < entriesList.length; i++) {
        if (entriesList.options[i].selected) {
            entryList[i] = entriesList.options[i].value;
            break;
        }
    }
 
    // Criteria indicating the data to be exported and the destination file
    var criteria = new Object();
    criteria.Type = "CalendarEntry";
    criteria.Data = new Object();
    criteria.Data.LocalIdList = entryList;
    // Destination file name
    var fileLocalName = document.getElementById("file").value;
    // Check the file name correctness
    var regPattern = new RegExp("^[a-zA-Z]+\.?[a-zA-Z]+$");
    if (!(regPattern.test(fileLocalName))) {
        alert("Incorrect file name: " + fileLocalName);
        return;
    }
    // Create full destination file name
    var fileName = "C:\\Data\\Others\\" + fileLocalName;
    criteria.Data.FileName = fileName;
    // Set the format of the destination file.
    if (document.getElementById("iCal").checked) {
        criteria.Data.Format = "ICal";
    } else {
        criteria.Data.Format = "VCal";
    }
 
    try {
        // Export the selected entries
        alert("Export begins");
        var result = serviceObj.IDataSource.Export(criteria, exportCallback);
        currentTransactionId = result.TransactionID;
        document.getElementById("state").innerHTML = "Exporting...";
    } catch (ex) {
        alert ("Error in exporting entries: " + ex);
    }
}
 
/**
 * Callback function for export asynchronous call.
 * @param transId A number representing the transaction that called the
 * callback handler.
 * @param eventCode A number representing the callback return status.
 * @param result An object for holding the callback return value
 */
function exportCallback(transId, eventCode, result) {
    // Check result of exporting
    if (result.ErrorCode != 0) {
        alert("Error in exporting: " + result.ErrorMessage);
    } else {
        alert("Data was exported successfully!");
    }
 
    document.getElementById("state").innerHTML = "";
    showEntries();
}
 
/**
 * Cancels the current action (exporting or importing).
 */
function cancelAction() {
    // Criteria determining the transaction which is to be canceled
    var criteria = new Object();
    // Get transaction id for the transaction which is to be canceled
    var transactionId = currentTransactionId;
    if (transactionId == undefined) {
        return;
    }
    criteria.TransactionID = transactionId;
    // Cancel the current action
    var result = calendarServiceObject.Cancel(criteria);
    if (result.ErrorCode !== 0) {
        alert("Cancel error: " + result.ErrorMessage);
    }
    showEntries();
}