I want to implement a serverside download process which reports its progress to the client.
I defined a global variable in my .aspx site class:
Public progressStatus As Integer
Then a start a new Thread to download the images in a List, which also changes the value of the global variable:
For Each imageUrl In imageFiles
currentUrlCount = currentUrlCount + 1
indexOfUrlSplit = imageUrl.LastIndexOf("/")
localFilename = imageUrl.Substring(indexOfUrlSplit + 1)
If localFilename <> "" Then
httpClient.DownloadFile(url, localImage)
progressStatus = CInt((currentUrlCount / totalUrlCount) * 100)
End If
Next
I use the SetIntveral Javascript methods to check for the value of the global variable every 2 seconds:
var progStat;
setInterval(function() {
progStat = <%=progressStatus%>;
document.write(progStat + "\n");
}, 2000);
Through debugging I checked that the global Variable in the Code behind is calculated and changed correctly. Anyway, Javascript keeps the initial Value of 0.
I would be glad if someone could help me with that problem!
Thank you very much everybody,
Max
When you use syntax like that:
progStat = <%=progressStatus%>;
progressStatus value is retrieved once and converted to string when page is rendered. At that time value is 0. It isn't retrieved from server every time you call that script.
It means javascript function rendered on your page looks like:
progStat = 0;
When you keep calling that function multiple times client-side it does not change as page isn't re-rendered.
You need to make use of an Ajax call to retrieve the value from the server. Use the result from the call together with JQuery and then update the UI
Related
I am trying to set the initial value in a Wijimo Autocomplete control which has been loaded from an external data source. The scenario being a form is used to create some new data and then is saved. Subsequently the data needs to be edited so it is reloaded into the form.
I can successfully use the Autocomplete on the initial form - the source list is a JSON Array of objects which is loaded into the controller. The app is using UI Router so I resolve this first.
When I save the data I serialise the selected Object from the Autocomplete control and is then saved to a Mongo DB store. When loading this data back in it is converted back to an object.
This is what the control looks like:
<wj-auto-complete
selected-index="selectedIndexCombo"
selected-item="selectedAirline"
items-source="airlineCodes"
display-member-path="Title"
placeholder="Airline Code"
max-items="50"/>
An example of the source list looks like this:
{
"#href":"\/airline.nsf\/api\/data\/collections\/name\/(LUAirlines)\/unid\/8DCD734E7BCDA24D80257C99003770C4",
"#link":
{
"rel":"document",
"href":"\/airline.nsf\/api\/data\/documents\/unid\/8DCD734E7BCDA24D80257C99003770C4"
},
"#entryid":"98-8DCD734E7BCDA24D80257C99003770C4",
"#unid":"8DCD734E7BCDA24D80257C99003770C4",
"#noteid":"FB2",
"#position":"98",
"#siblings":100,
"#form":"Airline",
"AirlineCode":"WN",
"Airline":"Southwest Airlines",
"Title":"WN - Southwest Airlines"
}
So when the form is initially created the controller property selectedAirline is correctly set with the selected Object.
So this works fine in the save function:
$scope.formData.selectedAirline = JSON.stringify($scope.selectedAirline);
But when reloading in the data:
AirlineInfoFactory.loadAirlineInfo($scope.reference).then(function success(response) {
$scope.selectedAirline = eval('(' + response.data.selectedAirline + ')');
$scope.information = response.data.information;
$scope.dataLoaded = true;
console.log($scope.selectedAirline)
$scope.selectedIndexCombo=11;
})
The autocomplete control does not bind to the selectedAirline property.
I tried using the selected-index attribute on the directive so see if I could just change it to something when the data loads but it doesnt work either. I suspect its to do with the digest loop but I am not sure.
Any ideas?
Thanks
I tried to replicate the scenario by reloading the data and setting the selectedAirline property and it works well withe latest version 32. Here is the fiddle:
http://jsfiddle.net/n1kpkcud/2/
` $scope.countries = initialList;
$scope.selectedAirline = '';
$scope.setItem = function () {
$scope.countries = reloading;
$scope.selectedAirline = 'Yemen';
}`
I would suggest you to update this fiddle so that it replicates the issue and I can suggest you accordingly.
I am dynamically adding kml files to google earth. For this, I have written javascript functions to add a kml and to remove a kml. These functions work fine for the first time for a kml. But if called again they do not respond. This happens for each kml that I try to add or remove. If I keep the page on browser for some time, then these functions again respond once and again become unresponsive.
function add(id, fileurl)
{
var link = ge.createLink('');
var href= fileurl;
link.setHref(href);
var networkLink = ge.createNetworkLink("'" + id + "'");
networkLink.set(link, true, true);
ge.getFeatures().appendChild(networkLink);
}
function remove(id)
{
for(var i=0; i<ge.getFeatures().getChildNodes().getLength(); i++)
{
if(ge.getFeatures().getChildNodes().item(i).getId() == id || ge.getFeatures().getChildNodes().item(i).getId() == "'" + id + "'")
{
id = ge.getFeatures().getChildNodes().item(i).getId();
ge.getFeatures().removeChild(ge.getElementById(id));
break;
}
}
The issue is that you can't re-add a feature using an ID that you have already used until all references to it have been released. This is usually done by the internal garbage collector - but you can also force it by calling release() on the object you are deleting. This ...
Permanently deletes an object, allowing its ID to be reused.
Attempting to access the object once it is released will result in an
error.
Also when an object is created with the API the object does not have a base address. In this case, the object can be returned by passing only its ID to getElementById(). This can then be used to remove the feature.
e.g.
function remove(id) {
ge.getElementById(id).release();
}
Really though I would look to avoid using IDs altogether and would simply keep a variable that points to the feature, then use that to remove. e.g.
function add(fileurl) {
var link = ge.createLink(''); //no id
link.setHref(fileurl);
var networkLink = ge.createNetworkLink(''); //no id
networkLink.set(link, true, true);
ge.getFeatures().appendChild(networkLink);
return networkLink;
}
var link1 = add("http://yoursite.com/file.kml");
var link2 = add("http://yoursite.com/file2.kml"); // etc...
// then to remove, simply...
link1.release();
link2.release();
OK. So I figured out that if you remove an object from GE, and then try to add another object with the same id, GE complains and won't create the object - unless some time (approx. 30 seconds in my case) has passed. This time actually is required by JavaScript to garbage collect the object.
Setting the object to null doesn't give immediate result but may help Garbage Collector.
Also release() method offered by GE does not help.
I've just moved to web development and need to know how i can implement below requirement using asp.net and vb.net.
I have three fields in a form which are filled by users. Based on these three values, i need to auto-populate the 4th field. I have planned to implement this in the following way
Write a separate class file with a function to calculate the possible values for the 4th fields based on 1st 3 inputs. This function can return some where between 1-10 values. So I've decided to use drop-down for 4th field, and allow users to select the appropriate value.
Call the above function in onchange function of 3rd field and take and use the return values to populate the 4th field. I'm planning to get the return values in array field.(Does this need a post back?)
Please let me know how if there is better way to implement this.
Thanks.
You may want to consider doing this with Javascript. You could read and control the fields pretty easily with pure Javascript, or using a nice library like jQuery (my favorite). If you did it this way, no post-back would be required and the 4th field would update immediately. (Nice for your users)
You can also do it with ASP.NET for the most part. "onchange" in ASP.NET still requires Javascript as far as I know, it just does some of it for you. A post-back will definitely happen when you change something.
You need javascript or to set autopostback=true on your form elements.
From a user perspective the best thing is to use javascript to populate the field for display, BUT when the form is submitted use your backend function to validate it. This will make sure the user didn't change the value.
An easy way is to use jQuery for the UI (that way you don't have to worry about long winded javascript and deal with browser compatibility as it's already taken care of for you) and have it call to the server for the data. For the server, your easiest route is to return JSON for looping values.
Include your jQuery:
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.3/jquery.min.js"></script>
Then add in a handle for the JavaScript:
<script type="text/javascript">
function autoPopulate() {
var value1 = $('#ddl1').val();
var value2 = $('#ddl2').val();
var value3 = $('#ddl3').val();
var url = 'path/to/your/file.aspx?value1=' + value1 + '&value2=' + value2 + '&value3=' + value3;
$.getJSON(url, function(data) {
data == null ? return false : data = eval(data);
var ddl = $('#ddl4')[0];
for (i = 0; i < data.length; i++) {
var option = new Option(data[i][0], data[i][1]);
if ($.browser.msie) {
ddl.add(option);
} else {
ddl.add(option, null);
}
}
}
}
</script>
(Yes, I know I used a native loop but I'm little lazy here today :) )
Now, for your server side code you'll want your code your page to return data in the format of:
[['value1','text1'],['value2','text2'],['value3','value3']]
so something like:
<script type="vb" runat="server">
Private Sub Page_Init()
// get your data
// loop through it and add in values
// ex.
Dim result As String = "[" //start multi-dimensional array
For Each Item As String In data
result += String.Format("['{0}','{1}'],", _value, _text)
Next
result = result.SubString(0, result.Length - 1) // removes trailing comma
result += "]" // closes off m-array
Response.Write(result)
Response.Flush()
End Sub
</script>
I don't know much about Flash but we are working on a site that has a flash form and when the users pick an option, like selecting a value from a drop down list, we need the value to be passed to asp.net server-side code. What's the easiest way to do this?
Flash can invoke server side service. So use GET or POST to pass data
You could explore these options:
1) Communicate between the SWF and the containing page through JavaScript
2) Communicate via asp.net webservices from the SWF directly to the webservice.
3) Not sure but could probably do a POST to a processing aspx page?
HTH
I think a good option is to use the XML class so consider this:
var xmlRequest = new XML();
xmlRequest.onLoad = parseXMLResponse;
xmlRequest.load("http://yourpathtoyourserver/file.aspx?listselectedvalue=something");
function parseXMLRequest(loaded)
{
trace("hi");
}
You can also have the page give you data back this way so it's not just one way communication.
Assuming you are using Action Script 2.
Read the important notes at the bottom of each codes pertain to sending and retrieving data from flash to .net page. Explanation of the code is in the comment inside the code.
Flash Part (Action Script 2)
//function to send collected form data to asp.net page
//use other control/button to call this function
//important: in order for the 'onLoad' event to work correctly, this function has to be 'Void'
function sendForm():Void
{
//create LoadVars object
var lv_in:LoadVars = new LoadVars();
var lv_out:LoadVars = new LoadVars();
//set onLoad event
lv_in.onLoad = function(success:Boolean)
{
//if success, meaning data has received from .net page, run this code
if (success)
{
//lv_in.status is use to get the posted data from .Net page
statusMsg.text = "Thank you for filling up the form!" + lv_in.status;
}
//if fail, run this code
else
{
statusMsg.text = "The form you are trying to fill up has an error!";
}
}
//this is the collected data from the form
lv_out.userName = txtUserName.text;
lv_out.userAddress = txtUserAddress.text;
lv_out.userBirthday = txtUserBirthday.text;
//begin invoke .net page
lv_out.sendAndLoad("ProcessDataForm.aspx", lv_in, "POST");
}
Important note:
The function that contain onLoad event, in this case sendForm function, has to be Void function, meaning it's not returning value. If this function return value, what happen is the function will be executed all the way without waiting for the returned data from .net page, thus the onLoad event will not be set properly.
.Net Part
public void ProcessData
{
//process the data here
Response.Write("status=processed&");
}
Important note:
To send data/message back to flash, you can use Response.Write. However, if you want Action Script to parse the posted message/data from .Net page keep in mind you have to include & symbol at the end of the message. When parsing data/message, Action Script will stop at & symbol, thus leave the rest of the message alone and only get the message under sent variable.
I want to use ICallBackEventHandler however when I use it to call back to the server I find that my form control objects don't have the latest form values. Is there a way to force populate the values with the form data?
Thanks.
Have a look at http://msdn.microsoft.com/en-us/magazine/cc163863.aspx.
In short, you have to clear the variable '__theFormPostData', and call the 'WebForm_InitCallback()' before the 'CallbackEventReference' script. This updates the form values with the user input values. Something like this:
// from the above link
string js = String.Format("javascript:{0};{1};{2}; return false;",
"__theFormPostData = ''",
"WebForm_InitCallback()",
Page.GetCallbackEventReference(this, args, "CallbackValidator_UpdateUI", "null"));
You obviously still dont have the same issue but wha you need to do is recall WebForm_InitCallback() prior to your JavaScript Callback Code. This will get the page to refresh the POST values in your Request.Form object.
When you now do a PostBack the values modified during Callbacks will be available. It goes without saying they will be available during Callbacks.
etc
function SomeCode()
{
__theFormPostCollection.length = 0;
__theFormPostData = "";
WebForm_InitCallback();
ExecuteMyCallbackMethod("yaday", "yadya");
}