Is it possible to send the result of a LINQ query as parameter to another .xaml file in WP7.
If yes then can you please explain via an example.
Thanks in advance
Here is my code
XDocument xml = XDocument.Load("VideoContent.xml");
var content = from query in xml.Descendants("Video") where (string)query.Element("Clip") == parameter
select new Video() { File = (string)query.Element("File") }
Now I need to pass the string in File to another .xaml using NAvigationService.
P.S I am very new to WP7 and LINQ
If you want to pass the string value, you can pass it as the Navigation parameter.
NavigationService.Navigate(new Uri("/NewPageName.xaml?file="+content.First().File, UriKind.Relative));
and then in the OnNavigatedTo handler of the New Page, get the 'file' string value like this
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
string file; //declare this before the page constructor
NavigationContext.QueryString.TryGetValue("file", out file);
}
Related
///first I have crated Popular class for storing values
public class Popular
{
public string trk_mnetid,trk_title , art_mnetid, art_name, image_url;
}
/// create popularplaylist class
public partial class PopularPlaylist : PhoneApplicationPage
{
Popular popobj = new Popular();
List<Popular> pop = new List<Popular>();
/* call json parsing it and show only "titles" in List form when i m click on perticular title i need to show details in next screen which i paser and store in popular popularplaylist class.
i use navigationservice call new screen
*/
NavigationService.Navigate(new Uri("/Popular_Module/PopularPlaylist.xaml", System.UriKind.Relative));
}
// plz tell me how to get list data in next screen
Use querystring.
Passing Value: In MainPage.xaml.cs add the following
The easiest way to pass a parameter is just to use a string, something like:
private void btnNavigate_Click(object sender, RoutedEventArgs e)
{
string url=String.Format("/Page1.xaml?parameter={0}",popular);
NavigationService.Navigate(new Uri(url, UriKind.Relative));
}
Getting Value: In Page.xaml.cs add the following
Note: It is important to override the OnNavigatedTo and after that you can use the NavigationContext to get the passed parameter.
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedTo(e);
List<string> parameterValue = NavigationContext.QueryString["parameter"];
}
Another popular syntax to get the value of the parameter is:
List<string> parameter = string.Empty;
if (NavigationContext.QueryString.TryGetValue("parameter", out parameter))
{
//do something with the parameter
}
Can't find the proper solution to this problem.
I am using [Serializable] (MVC3 Futures) in order to have a "wizard" with separate views. Here is the code in my controller to serialize:
private MyViewModel myData;
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var serialized = Request.Form["myData"];
if (serialized != null) //Form was posted containing serialized data
{
myData = (MyViewModel)new MvcSerializer().Deserialize(serialized, SerializationMode.Signed);
TryUpdateModel(myData);
}
else
myData = (MyViewModel)TempData["myData"] ?? new MyViewModel();
TempData.Keep();
}
protected override void OnResultExecuted(ResultExecutedContext filterContext)
{
if (filterContext.Result is RedirectToRouteResult)
TempData["myData"] = myData;
}
Further along in my controller I do something like this (just a snippet - code goes through wizard with next and back button strings):
public ActionResult Confirm(string backButton, string nextButton)
{
if (backButton != null)
return RedirectToAction("Details");
else if ((nextButton != null) && ModelState.IsValid)
return RedirectToAction("Submitted");
else
return View(myData);
}
In my .cshtml view, I have this:
#using (Html.BeginFormAntiForgeryPost())
{
#Html.Hidden("myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed))
...
#Html.TextBoxFor(m => model.Step.EMail)
...
}
Because I am using dynamics, I have to use a variable instead in the view:
var model = (MyViewModel) Model.myData;
in order to do the #Html.TextBoxFor above. And herein lies my probelm, because if I do #model MyViewModel instead, then I can't do model.Step.EMail. But because of dynamics, the #Html.Hidden won't work and I get the following error:
Compiler Error Message: CS1973: 'System.Web.Mvc.HtmlHelper'
has no applicable method named 'Hidden' but appears to have an
extension method by that name. Extension methods cannot be dynamically
dispatched. Consider casting the dynamic arguments or calling the
extension method without the extension method syntax.
I can switch to some other way of doing this without [Serializable], but then I have to convert a LOT of code. Is there any way to make this work?
The extension method is not identifying the method because, the data type does not match.
Try cast as object.
#Html.Hidden("myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed) as Object)
or
#Html.Hidden("myData", (Object)new MvcSerializer().Serialize(Model, SerializationMode.Signed))
It will works.
You can call
#(InputExtensions.Hidden(Html, "myData", new MvcSerializer().Serialize(Model, SerializationMode.Signed)))
instead of #Html.Hidden(...)
It is calling the extension method without the extension method syntax.
Consider this simple controller:
Porduct product = new Product(){
// Creating a product object;
};
try
{
productManager.SaveProduct(product);
return RedirectToAction("List");
}
catch (Exception ex)
{
ViewBag.ErrorMessage = ex.Message;
return View("Create", product);
}
Now, in my Create view, I want to check ViewBag object, to see if it has Error property or not. If it has the error property, I need to inject some JavaScript into the page, to show the error message to my user.
I created an extension method to check this:
public static bool Has (this object obj, string propertyName)
{
Type type = obj.GetType();
return type.GetProperty(propertyName) != null;
}
Then, in the Create view, I wrote this line of code:
#if (ViewBag.Has("Error"))
{
// Injecting JavaScript here
}
However, I get this error:
Cannot perform runtime binding on a null reference
Any idea?
#if (ViewBag.Error!=null)
{
// Injecting JavaScript here
}
Your code doesnt work because ViewBag is a dynamic object not a 'real' type.
the following code should work:
public static bool Has (this object obj, string propertyName)
{
var dynamic = obj as DynamicObject;
if(dynamic == null) return false;
return dynamic.GetDynamicMemberNames().Contains(propertyName);
}
Instead of using the ViewBag, use ViewData so you can check for the of the item you are storing. The ViewData object is used as Dictionary of objects that you can reference by key, it is not a dynamic as the ViewBag.
// Set the [ViewData][1] in the controller
ViewData["hideSearchForm"] = true;
// Use the condition in the view
if(Convert.ToBoolean(ViewData["hideSearchForm"])
hideSearchForm();
I would avoid ViewBag here completely.
See my thoughts here on this:
http://completedevelopment.blogspot.com/2011/12/stop-using-viewbag-in-most-places.html
The alternative would be to throw a custom error and catch it. how do you know if the database is down, or if its a business logic save error? in the example above you just catch a single exception, generally there is a better way to catch each exception type, and then a general exception handler for the truly unhandled exceptions such as the built in custom error pages or using ELMAH.
So above, I would instead
ModelState.AddModelError()
You can then look at these errors (assuming you arent jsut going to use the built in validation) via
How do I access the ModelState from within my View (aspx page)?
So please carefully consider displaying a message when you catch 'any' exception.
You can use ViewData.ContainsKey("yourkey").
In controller:
ViewBag.IsExist = true;
In view:
if(ViewData.ContainsKey("IsExist")) {...}
I need to test this but:
#if (ViewBag.ABoolParam ?? false)
{
//do stuff
}
I think will give you either the value of the ViewBag property, or return a default value if missing.
I'm try to retrieve the contents of a texblock and put it in a webbrower in order to avoid html content :
desc1 is a variable recovered OnNavigatedTo method when navigating between pages
the problem is that I generate this exception:
invalid ioerationexception
plz help
thank you
var desc1 = NavigationContext.QueryString["desc"] as String;
BrowserControl.NavigateToString("<html>"+desc1+"</html>");
I tried this and it this works for me,
try and set a variable to your desc1, then go back to the xaml editor and create a loaded event handler for your page which will do the webbrowser task
string s;
public MessAbout()
{
InitializeComponent();
var desc1 = "text" as string;
s = desc1;
}
private void loaded(object sender, RoutedEventArgs e)
{
webBrowser1.NavigateToString("<html>" + s + "</html>");
}
I have a simple user control in Windows Phone 7 and I want to get access to the querystring collection from the user controls Constructor. I have tried many ways and cannot seem to get acess to the containing XAML's querystring collection.
Essentially I am navigating to the page and the my user control is going to access the querystring value to write the value back to the interface.
Am I missing adding an assembly or reference or something?
I am not sure you should be trying to get at the information from the page's constructor, as it won't necessairly get called every time you land on this page. A better approach is to override the OnNavigatedTo method inherited from PhoneApplicationPage. Looking a little more carefully at your question, you may be trying to do this within a control embedded in the page, in which case you need to get at the Page in order to obtain the navigation information.
Regardless, the NavigationContext property from the page has a QueryString parameter that you can use to access the information you're after.
The following example assumes I have a parameter named "Message" in the query string when navigating to this page:
public partial class MyPage : PhoneApplicationPage
{
// Constructor
public MyPage()
{
InitializeComponent();
}
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedTo(e);
String navigationMessage;
if (NavigationContext.QueryString.TryGetValue("Message", out navigationMessage))
{
this.textBlock1.Text = navigationMessage;
}
}
}
Sorry about that - I started to get there, and thanks for the clarification. Your best bet then is to walk up the visual tree from your control to find the Page, then you can have at the NavigationContext. In my sample below, I have a button on a custom control within the page, whose click event finds the nav context and looks for a certain navigation parameter - I couldn't tell from the question or your follow-up what would drive the control to "want" to find the content of the query string.
(Note about getting info from the ctor follows the code below)
public partial class WindowsPhoneControl1 : UserControl
{
public WindowsPhoneControl1()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
GetTheQueryString();
}
private void GetTheQueryString()
{
var result = "No Joy";
var page = FindRootPage(this);
if (page != null)
{
if (page.NavigationContext.QueryString.ContainsKey("Param"))
{
result = page.NavigationContext.QueryString["Param"];
}
}
queryStringText.Text = result;
}
private static PhoneApplicationPage FindRootPage(FrameworkElement item)
{
if (item != null && !(item is PhoneApplicationPage))
{
item = FindRootPage(item.Parent as FrameworkElement);
}
return item as PhoneApplicationPage;
}
}
Note that this won't work from the ctor because of how Xaml works...the Xml tag drives the ctor to be called, then properties are set as indicated, then it is added as a child/item/etc in its container. If you do need to get at the context ASAP using this "walk up the tree" technique, handle the Control's Loaded event, by which time the control does have a parent and a tree that can be walked...
public WindowsPhoneControl1()
{
InitializeComponent();
Loaded += WindowsPhoneControl1_Loaded;
}
private void WindowsPhoneControl1_Loaded(Object sender, RoutedEventArgs e)
{
GetTheQueryString();
}
I would add a property to the UserControl subclass that would be set by the page in its OnNavigatedTo() method.