Making multiple Async calls in a loop - silverlight-4.0

I am loading (via drag and drop) multiple documents in a SilverLight 4 RIA application. The AddNewXDocument asyn call (in the code below) works great when i have just one record in the queue- i.e. _uploadedDocuments.Count =1. If I drop multiple files, however, the second AddNewXDocument method is called before the Submit event for the first file completes. I get the "A SubmitChanges operation is already in progress on this DomainContext" error.
How can I use IAsyncResult to delay calling the AddNewXDocument method for file 2 till after the Submit event for file 1 completes. Can I also tie in a visual indicator in the loop to inform user that a Load process is in progress ??
foreach (var updDoc in _uploadedDocuments)
{
string docTitle = GetUniqueFileName(updDoc.Title.Replace(updDoc.FileExtension, ""), updDoc.FileExtension.ToLower());
var doc = new XDocument();
doc.Description = docTitle;
_myViewModel.AddNewXDocument(doc);
}

Related

notifyDatasetchanged not working for ArrayAdapter

I am trying to implement 2 AutoCompleteTextView. First one holds the value, on click of one of them will populate the data in second AutoCompleteTextView, all works and data gets loaded correctly however when I try to call notifyDataSetChanged on the second adapter which populates the second field that does not get changed.
I also wrote that piece of code inside a Handler too, however that does not seems to work either.
branchAdapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1,branchNames);
et7.setAdapter(branchAdapter);//et7 is the AutoCompleteTextView //branchname is the ArrayList
in some method I clean up the ArrayList and add the new data into it and then call notifyDataSetChanged like below
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
#Override
public void run() {
branchAdapter.notifyDataSetChanged();
}
});
Which is not updating the list. What should be the correct way here to update data?
#Saty, I guess i am a little late to the party. I am answering, keeping in mind that, it may help somebody in future.
Cleanup the adapter as well using branchAdapter.clear() method. Then add new items to the adapter using branchAdapter.addAll(String... items) method. Now, call branchAdapter.notifyDataSetChanged() method. This will work.
Try resetting listview instead.
ListView lv = (ListView)findViewById(R.id.lv);
ArrayAdapter adapter = new ArrayAdapter(/*with all parameters*/);
lv.setAdapter(adapter);

Invoking Method of Presenter on Activation

I'm using Smart Client Software Factory 2008. In the module controller, I have code that creates a new child controller only if it hasn't been created, by doing something like the following:
Dim key = "Item-" + item.ID.ToString()
Dim childWorkItem = Me.WorkItem.WorkItems.Get(Of ControlledWorkItem(Of ItemWorkItemController))(key)
If childWorkItem Is Nothing Then
childWorkItem = Me.WorkItem.WorkItems.AddNew(Of ControlledWorkItem(Of ItemWorkItemController))(key)
Else
childWorkItem.Activate()
End If
Multiple items reuse the same key, so when that action is triggered, it shows the tab instead of creating a new instance of it. This works great.
However, there is one drawback. Once activated, I need to run a check within that item's presenter. So I need to call a method on the presenter. Is there a way to invoka a method on the presenter, or is there an event that runs on the view when the work item is activated? I'm not sure how to make that happen?
Thanks.
If you are using a Smart Part as your View you should be able to accomplish this using the IWorkspace.SmartPartActivated event.
This is how I have it setup in my project. I apologize, my code is all in C# but you should be able to apply it in VB relatively easily.
The WorkItemController class has the Activate method setup like this
ISmartPartView _smartPartView
public void Activate()
{
IWorkspace contentWorkspace = this.WorkItem.Workspaces[WorkspaceNames.ShellContentWorkspace];
contentWorkspace.Activate(_smartPartView);
WorkItem.Activate();
}
In the ISmartPartView Presenter class you should be able to create a handler for the SmartPartActivated event like this:
IWorkspace contentWorkspace = this.WorkItem.Workspaces[WorkspaceNames.ShellContentWorkspace];
contentWorkspace.SmartPartActivated += workSpaceSmartPart_ActivatedHandler;
In the workSpaceSmartPart_ActivatedHandler event handler, you can check the SmartPart being activated and if its your ISmartPartView class you can run the desired code.

Variable in controller is lost when passing between views

I am currently stuck with an issue in my MVC 4 application. I have private variable in controller, that holds instance of a simple class:
private InstallationStatus status = null;
When data get submitted on a view, it gets filled like this:
InstallationStatus installStatus = Install();
if (installStatus != null)
{
status = installStatus;
TempData["installPercent"] = 0;
return View("InstallationProgress", status);
}
This part works as intended, variable is set to the instance as it should be.
After that view periodically checks another variable (using ajax):
<script type="text/javascript">
$(document).ready(function () {
var progress = 0;
$("div.status-message").text("Progress: " + progress + "%");
var statusUpdate = setInterval(function () {
$.ajax({
type: 'GET',
url: "/AppStart/GetInstallProgress",
datatype: "application/html; charset=utf-8",
success: function (data) {
progress = parseInt(data);
if (progress >= 100) {
clearInterval(statusUpdate);
var data = $(this).serialize();
$.ajax({
type: 'POST',
url: "#Url.Action("CompletedStatus", "AppStart")",
success: function () {
window.location = "/Login/Login"
}
});
}
$("div.status-message").text("Progress: " + progress + "%");
}
});
}, 2000);
});
</script>
When it calls "CompletedStatus" action on the controller, variable "status" on the controller is null (the instance set previously is not there?
How do I ensure that its value will persist? It seems to me like whole instance of controller gets lost, but that doesnt really matter to me - the source for "status" is webservice and once I get the instance of InstallationStatus, I cant get it again - I need to keep it.
I tried using TempData to store it but since there can be more than one step between storing it and retrieving it TempData proved unreliable.
The final process is:
Request installation status and navigate to view for installation progress (status will be received when progress will finish).
navigate to view where I will by updating installation progress
using javascript whenever I get callback from server with info about
progress
when installation finishes (status is returned) pass that status to
another view
In the example above I have some dummy code-behind, so the status is returned immediately, but that has no impact on the problem I have.
Currently I can do 1 and 2 and I can call the final view, but I cant pass the status in there because I dont have it on controller anymore and TempData are not reliable for this (sometimes it is still there, sometimes it is not).
Any help will be greatly appreciated.
When it calls "CompletedStatus" action on the controller, variable
"status" on the controller is null (the instance set previously is not
there?
How do I ensure that its value will persist?
private InstallationStatus status = null;
It won't unless it's a static value and that would be a very bad thing to do. Remember that variable values (private members' values) are only scoped within the http request. If you do another request then that's a totally whole new scope for your private variables.
I tried using TempData to store it but since there can be more than
one step between storing it and retrieving it TempData proved
unreliable.
That's because TempData will not have the value you expect it to have once you do another request. One good example of using this TempData is when you want to pass/move some values between a POST and GET, that is when you do a POST and do a redirect. TempData does not fit your case.
Now for a possible solution to your scenario, a good question is: is the installation process called once? Is it unique per user? If it is, which I highly suspect it is, then you need to uniquely identify each request. You can simply use a GUID to identify each request. Save that into your database (better than saving in a session) along with some other information like the status of the installation. Pass that guid back to your client and let them pass it back to the controller and retrieve an update on the status of the installation.

Adding content to silver light controls from database using wcf ria services

I am trying to retrieve strings from the database and add it as content to the controls on my page before it loads(somewhat like a custom localization). I retrieve my strings from the database uing ria services as follows:
**
Web.DomainService1 context = new Web.DomainService1();
LoadOperation<Web.LocalizationTab>LoadOp=context.Load(context.GetLocalizationTabsQuery(currentCulture, moduleName));
Dictionary<string, string> localizationDictonary = new Dictionary<string, string>();
List<Web.LocalizationTab> localList = new List<Web.LocalizationTab>();
LoadOp.Completed += (s, e) =>
{
localList = LoadOp.Entities.ToList<Web.LocalizationTab>();
//System.Windows.MessageBox.Show(localList.Count.ToString());
foreach (Web.LocalizationTab item in localList)
{
// var control = this.FindName(item.Control_ID.ToString());
if (!localizationDictonary.ContainsKey(item.Control_ID))
{
localizationDictonary.Add(item.Control_ID, item.Control_Text);
}
}
};**
This piece of code is in a separate class called utilities.cs.
now in my Mainpage.xaml.cs i need to get this dictionary with values and then set the controls with the strings from the dictionary.
my problem is that when i do the following in the constructor of Mainpage.xaml.cs:
utilities.getDict(ModuleName);
button1.Content = localizationDictonary["button1"].ToString();
i get an exception as the dictionary doesnt contain values at that point of time.. The load completed event of getting data from the database gets fired only after my constructor is exited. now how do i go about setting my controls automatically in this particular scenario??
Try loading your dictionary in the Silverlight Application class StartUp event. This should ensure that your Dictionary is loaded (and could be placed in the Application Resources for retrieval elsewhere in your application).
You'll need to wait for the GetLocalizationTabsQuery to complete before instantiating your MainPage. In your App.xaml.cs file, you can start the query, add a query completed handler, and only create the MainPage when the query completed handler gets called.

Silverlight is not fetching data from my WCF RIA service

I just started learning Silverlight by walking through the labs posted on Channel9. When I tried to explore a little bit I found that my queries were not working as I thought they would.
To recreate what I have done you would need to create a new Silverlight Business application, create a data entity that is pointed to the Adventureworks LT db, and generate the web services for those entities (including edit).
I then simply drug a RichTextbox to Home.xaml and in Home.xaml.cs I added this code first to OnNavigatedTo and when that didn't work to the constructor.
AdventureWorksDomainContext ctx = new AdventureWorksDomainContext();
EntityQuery<Product> query =
from p in ctx.GetProductsQuery()
select p;
LoadOperation<Product> loadOp = ctx.Load(query);
var paragraph = new Paragraph();
foreach (var product in loadOp.Entities)
{
paragraph.Inlines.Add(new Run { Text = product.Name });
}
richTextBox1.Blocks.Add(paragraph);
When I run the page I never see loadOp.Entities contain a value and I only see the query I expect, go across the wire after all my code has been executed.
I feel like I'm missing something fundamental and this will make more sense if I can find someone to explain it to me.
Thanks,
Eric
The problem is related to the how you are loading the data. The actual Load operation is asynchronous, as is all Silverlight network calls. You are callingt ctx.Load(query) and then immediately setting the paragraph to the entities. You need to use a callback when Load is completed. Something like this,
AdventureWorksDomainContext ctx = new AdventureWorksDomainContext();
EntityQuery<Product> query =
from p in ctx.GetProductsQuery()
select p;
LoadOperation<Product> loadOp = ctx.Load(query,() =>
{
var paragraph = new Paragraph();
foreach (var product in loadOp.Entities)
{
paragraph.Inlines.Add(new Run { Text = product.Name });
}
richTextBox1.Blocks.Add(paragraph);
});
Since you aren't using the entities directly in a binding and are just iterating them, you need to make sure you wait until they are loaded. I can't remember the actual signature of the Load method, so you may need to modify my lambda to make it work.