Develop Reference

Windows Phone 8 Databound App and back button

I've something that I can't get myself understand. I'm making an app with databound template. I put a textbox on mainpage and a button. when i type something in textbox and press on button it navigates to the listing page and that content comes from web and then if i press on back button and make a new search the results from previous search stays there. how can i reset/clear or disable cache of that page?

It would be helpful if you could post your XAML and code-behind, but I will attempt to make a jab at an answer. Where are you referencing the call to get the data from the web? If it is in the constructor of the page, then that is why the previous search stays there. What is probably happening is the first search constructs the secondary page, does your web call, and binds your data to the page. Then when you press the back button, and click it again, the page is already constructed, so it uses the same data.
It is probably wise to call your web service in the OnNavigatedTo override method. From the first page, you can pass parameters to your secondary page (i.e., pass the search term, then pass the search term into your web service).
Here is an example of passing parameters between pages: http://developer.nokia.com/Community/Wiki/Passing_parameters_while_navigating_between_pages_on_Windows_Phone
Also, make sure your Data Context for the second page is appropriately set each time the page is navigated to, since you have a data bound application.
Without code, I can't really help other than giving these things to think about.

Click Gmail Refresh button

I am writing a simple personal app that has a browser control and I want it to automatically "Refresh" gmail to check it more often than it does by default. There are monkey scripts that do this but I'm trying to add my personal style to it.
Anyhow, I've looked around and found everything but what I can do in csharp using the browser control.
I found this:
// Link the ID from the web form to the Button var
theButton = webBrowser_Gmail.Document.GetElementById("Refresh");
// Now do the actual click.
theButton.InvokeMember("click");
But it comes back with null in 'theButton' so it doesn't invoke anything.
Anyone have any suggestions?

It's been awhile since I've used JavaScript, but given the other answers and comments that there is no real ID associated with the element, could you do something like the following:
Search all Div's with an attribute of Role == 'Button' and an InnerHtml == 'Refresh'.
Once the correct InnerHtml is found, get the Element.
Invoke the click on the found Element.
Again, this may be blowing smoke, but thought I'd throw it out there.
edit: Just realized you are doing this with C# and a browser control; however, the concept would still be the same.

The best suggestion I could give you at this point involves an existing API that is used for .NET web browser based automation:
http://watin.org/
Since the div tag with the desired button really only seems to identify itself with the class name, you could use the Find.BySelector(“”) code included with the most recent version of watin.

MultiViewControl issues

I'm presently in the process of reworking a MultiViewControl based wizard process for our web application. I am having an rough time trying to make sense of the order that events are happening (Page_Load, Init, prerender, etc). Does anyone out there on the interwebs have details on dealing with one of these controls? Please don't just say 'google' it. I've done that and have yet to find a good, comprehensive site yet.
Admittedly, I haven't really elaborated on the problems I'm having with this control, so I'll try to do that:
Primary problem is the initialization of UserControls that live in different Views. In the existing codebase, the programmer was using a combination of multiviewcontrol.ActiveViewIndex = WHATEVER and Response.Redirect("PageWithMultiView.aspx?nextstep") and it made it all very convoluted. My task is to attempt to remove the Response.Redirect calls and use only the setting of the ActiveViewIndex. Is this even possible? Also, there are some cases where I need to initialize a control in a particular view only on the initial load and not on subsequent postbacks. I can use something like the IsPostBack flag but this is only ever set to false on the initial load. Subsequent reloads IsPostBack == true. I basically want to have IsPostBack set to false for the initial load of each View. Can this be done without doing a Response.Redirect to itself?
Hopefully this will make some sense to someone out there.
Thanks.
Greg.

I am having an rough time trying to
make sense of the order that events
are happening (Page_Load, Init,
prerender, etc).
Here you have all details about ASP.NET page lifecycle and events: http://msdn.microsoft.com/en-us/library/ms178472.aspx .
In terms of MultiView - you should NEVER use Response.Redirect when you work with MultiView.
If user can not switch to previous view then you can check previous ActiveViewIndex value before setting it to the new value, e.g.
if (mv.ActiveViewIndex != newIndex)
{
// this view is displayed for the first time
}
If user can switch to the previous views, I suggest to place an information about already used views in session or by placing hidden field on the form with ids of the views that have already been displayed and to use that information instead of IsPostBack.

URL and Query management Asp.Net C#

Ok so while back I asked question Beginner ASP.net question handling url link
I wanted to handle case like this www.blah.com/blah.aspx?day=12&flow=true
I got my answer string r_flag = Request.QueryString["day"];
Then what I did is placed a code in Page_Load()
that basically takes these parameters and if they are not NULL, meaning that they were part of URL.
I filter results based on these parameters.
It works GREAT, happy times.... Except it does not work anymore once you try to go to the link using some other filter.
I have drop down box that allows you to select filters.
I have a button that once clicked should update these selections.
The problem is that Page_Load is called prior to Button_Clicked function and therefore I stay on the same page.
Any ideas how to handle this case.
Once again in case above was confusing.
So I can control behavior of my website by using URL, which I parse in Page_Load()
and using controls that are on the page.
If there is no query in URL it works great (controls) if there is it overrides controls.
Essentially I am trying to find a way how to ignore parsing of url when requests comes from clicking Generate button on the page.

Maybe you can put your querystring parsing code into IsPostBack control if Generate button is the control that only postbacks at your page.
if (!IsPostBack)
{
string r_flag = Request.QueryString["day"];
}
As an alternative way, at client side you can set a hidden field whenever user clicks the Generate button, then you can get it's value to determine if the user clicked the Generate button and then put your logic there.

NullReferenceException on Page_Load

I'm trying to edit a textbox's text in a Page_Load form on an ASP.NET page, but when I try to edit TextBox1.Text it throws a NullReferenceException because the TextBox has not yet been instantiated. Specifically what I'm trying to implement is this: http://www.codeproject.com/KB/user-controls/popupcalendarcontrol.aspx but it is written for an older version of ASP.NET and does not work for me. Is there a way to instantiate the controls at the start of Page_Load? or another event that I can catch on load? With a normal windows form I would call InitializeComponent() in the constructor.

There are absolutely different events you can attach to but it sounds like the page isn't loading the controls properly because they should be available by that point. You can take a look at the ASP.NET Page Life Cycle for more information.

Does the TextBox sit within a bound control, such as a FormView, GridView, DataList, etc? If so, then the control won't exist until after the databinding happens. Once that event happens, you can do something like
DirectCast(myDataList.SelectedRow.FindControl("myTextBox"),
TextBox).Text

I know that I am a bit behind in getting to this question BUT I have found something unusual that I can NOT find documented anywhere. It would appear that IF your page is "under" a Master Page, and IF you refer to ANYTHING on said master page, the controls to your current page are null - EVERYONE of them. I found this out by referencing "Master.Environment" - a public string - during my InitializeCulture method and having the FIRST control on my current (Default.aspx) page be null during Page_Load() - WHATEVER the first control was.
I know I am late but if this can help ANYBODY, I want the word out.