I'm using two custom controls. One gathers the criteria for a search, and the other displays a list. These two controls need to remain seperate for the time being.
What is the best method of transfering data from the search control, to the list control?
I'm thinking of ViewState, Session or wrapping both within a UpdatePanel and using custom events??
Maybe you can create a delegate and an event to pass a list of searchvalues? This way you can easily add another or multiple display controls in case that ever becomes necessary.
Note that this is just some quick sample code that should be optimized/improved.
public class SearchControl
{
public delegate void SearchEventHandler(object sender, Dictionary<string, string> SearchValues);
public event SearchEventHandler OnSearch;
public SearchControl()
{
btnSearch.Click += new EventHandler(Search);
}
protected void Search(object sender, EventArgs e)
{
if (OnSearch != null)
{
Dictionary<string, string> searchValues = new Dictionary<string, string>();
searchValues.Add("name", "John");
searchValues.Add("age", "24");
OnSearch(this, searchValues);
}
}
}
public class DisplayControl
{
public void ShowResults(Dictionary<string, string> SearchValues)
{
// Some logic here...
}
}
public class YourWebPage
{
SearchControl searcher = new SearchControl();
DisplayControl displayer = new DisplayControl();
public YourWebPage()
{
searcher.OnSearch += new SearchControl.SearchEventHandler(searcher_OnSearch);
}
public void searcher_OnSearch(object sender, Dictionary<string, string> SearchValues)
{
displayer.ShowResults(SearchValues);
}
}
Expose a public property of the type of data you have, then a public method to bind the data to your list
If the controls are separate, they should probably not be communicating directly. After all - most other .NET controls don't communicate directly either. I can only think of two exceptions - child/parent controls sometimes communicate basic information; and data-bound controls sometimes communicate directly with a DataSource. But that's largely it.
If you need to hook up two adjacent controls then the "normal" way of doing it is that their container takes care of it. Like, if a button click affects the text on the label, it is the Page (container for them both) that handles the Click event and sets the Text property.
Alternatively you could also give your ListControl a property called FindControl and assign it in Page_Init or something. But if the coupling is so tight, you might wonder if it would not be better to merge the controls too.
It depends on where the search is performed and what data is transferred between the controls. In my opinion, it is probably best to just pass the criteria to the page and have the page run the search bind them to the list control to display the results.
Related
I'm trying to make use of the new SearchHandler implemented as part of Xamarin Forms 4. I've found it pretty easy so far to get suggestions populated but now I want to raise an event, or follow the suggested method of handling when a search is confirmed.
public class FoodSearchHandler: SearchHandler
{
IFoodDataStore dataStore = new FoodDataStore();
protected override void OnQueryConfirmed()
{
base.OnQueryConfirmed();
// What to do here?
}
protected override void OnQueryChanged(string oldValue, string newValue)
{
base.OnQueryChanged(oldValue, newValue);
if(!string.IsNullOrWhiteSpace(newValue)
{
// Populate suggestions
ItemsSource = dataStore.GetSuggestions(newValue);
}
else
{
ItemsSource = null;
}
}
}
public partial class FoodsPage : ContentPage
{
ObservableCollection<Food> Foods = new ObservableCollection<Food>();
public ItemsPage()
{
InitializeComponent();
// Wire up the search handler
Shell.SetSearchHandler(this, new FoodSearchHandler());
BindingContext = this;
}
}
Unfortunately, althought the alpha docs mention the search handler they don't contain any details on how to use it and the sample apps only demonstrate populating the suggestions.
Does anyone out there have a pointer to offer on how I should be notifying my ContentPage that my SearchHandler confirmed a search?
So, after reading the Shell docs some more, it seems what I want to do in this situation is use of Shell's new Navigation and navigate to a route passing the search text as a query, for example:
protected override void OnQueryConfirmed()
{
base.OnQueryConfirmed();
var shell = Application.Current.MainPage as Shell;
shell.GoToAsync($"app:///fructika/search?query={Query}", true);
}
N.B. It doesn't look like passing data works right now or if it does I'm doing it wrong but I'll raise a separate question about that.
I've 2 user controls named UCCreateProfile.ascx (used for creating/editing profile data) and UCProfileList.ascx (used to display profile data in GridView). Now whenever a new profile created I want to update my UCProfileList control to show new entry.
The best solution against above problem I've to go for Observer Pattern. In my case UCCreatedProfile is a Subject/Observable and UCProfileList is a Observer and as per pattern definition when observer initialized it knows who is my Subject/Observable and add itself into Subject/Observable list. So whenever a change occurred in Subject/Observable it will be notified.
This pattern best fit my requirements but I'm getting few problems to implement this describe as follows.
I'm working under CMS (Umbraco) and I don't have any physical container page (.aspx). What I've to do is find UCCreateProfile (Subject/Observable) in UCProfileList (Observer) onLoad event using following code.
private Control FindCreateProfileControl()
{
Control control = null;
Control frm = GetFormInstance();
control = GetControlRecursive(frm.Controls);
return control;
}
where GetFormInstance() method is
private Control GetFormInstance()
{
Control ctrl = this.Parent;
while (true)
{
ctrl = ctrl.Parent;
if (ctrl is HtmlForm)
{
break;
}
}
return ctrl;
}
and GetControlRecursive() method is
private Control GetControlRecursive(ControlCollection ctrls)
{
Control result = null;
foreach (Control item in ctrls)
{
if (result != null) break;
if (item is UCCreateProfile)
{
result = item;
return result;
}
if (item.Controls != null)
result = GetControlRecursive(item.Controls);
}
return result;
}
this way I can find the UCCreateProfile (Subject/Observable) user control in UCProfileList (Observer) but the way to find out the (Subject/Observable) is not so fast. As you can see I need to loop through all controls and first find the HtmlForm control and then loop through all child controls under HtmlForm control and find the appropriate control we're looking for.
Secondly, placement of the user controls in container if very important my code will only work if UCCreatedProfile.ascx (Subject/Observable) placed before UCProfileList.ascx (Observer) because this way UCCreateProfile will load first and find in UCProfileList. But if someone changed the position of these 2 controls my code will not work.
So to get rid of these problems I need some solution which works faster and independent of the position of the controls.
I've figured out some solution as described below. Please do let me know if it is a good way of doing this. If there is an alternative, please let me know.
I've a session level variable (a dictionary with Dictionary<ISubject, List<Observer>>) . No matter which user control initialized/loaded first, User Control will add itself into this dictionary.
If Subject/Observable added first, the corresponding observers will be found in this dictionary.
If Observer added first it will added to the dictionary with a null entry. When the Subject added, the association is made.
Regards,
/Rizwan
The Observer pattern is best implemented in .NET via events and delegates. If you use events and delegates, the Dictionary you mention becomes completely unnecessary. See for example this code below (only important pieces shown):
public partial class UserProfile : System.Web.UI.UserControl
{
//This is the event handler for when a user is updated on the UserProfile Control
public event EventHandler<UserUpdatedEventArgs> UserUpdated;
protected void btnUpdate_Click(object sender, EventArgs e)
{
//Do whatever you need above and then see who's subscribed to this event
var userUpdated = UserUpdated;
if (userUpdated != null)
{
//Initialize UserUpdatedEventArgs as you want. You can, for example,
//pass a "User" object if you have one
userUpdated(this,new UserUpdatedEventArgs({....}));
}
}
}
public class UserUpdatedEventArgs : EventArgs
{
public User UserUpdated {get;set;}
public UserUpdatedEventArgs (User u)
{
UserUpdated=u;
}
}
Now subscribing to the UserUpdated event from the UserProfile control on the UserListControl is as easy as this:
public partial class UserList : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
//Find the UserProfile control in the page. It seems that you already have a
//recursive function that finds it. I wouldn't do that but that's for another topic...
UserProfile up = this.Parent.FindControl("UserProfile1") as UserProfile;
if(up!=null)
//Register for the event
up.UserUpdated += new EventHandler<UserUpdatedEventArgs>(up_UserUpdated);
}
//This will be called automatically every time a user is updated on the UserProfile control
protected void up_UserUpdated(object sender, UserUpdatedEventArgs e)
{
User u = e.UserUpdated;
//Do something with u...
}
}
I'm using Model-View-Presenter framework. When Loading a page, I'm having trouble setting the selected item that came from the Database.
In view, I know I need:
protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e)
{
presenter.DdlStatusSelectedIndexChanged();
// what should this pass?
}
Then in Presenter:
public void DdlStatusSelectedIndexChanged()
{
view.DdlStatus = ???
// Should I pass the SelectedIndex?
}
I also think that part of my problem is that DdlStatus I have as a List.
Interface:
List<StatusDTO> DdlStatus { set; get; }
Does anybody have some simple examples of this?
The best I found is here (but needs formatted!) --->
http://codebetter.com/blogs/jeremy.miller/archive/2006/02/01/137457.aspx
Thanks!
Which framework are you using? The typical way the presenter/view relationship works is through events; the view defines events that the presenter attaches to, to receive those state change notifications. There are other options too.
Your model should contain the list of statuses and the selected status. Depending on the "flavor" of MVP, you would either have the presenter call a property on the view to pass it the selected index, and your view would pass it to the control, or the view takes the index from the model directly.
HTH.
I figured this out. It's a bit of a cheese but ...
public int DdlStatusSelectedIndex
{
set
{
for (int i = 0; i < ddlStatus.Items.Count; i++)
{
if (ddlStatus.Items[i].Value.Equals(value.ToString()))
{
ddlStatus.SelectedIndex = value;
}
}
}
}
I've a static page method in web form application and I want to call method on private class level variable from it as shown below. I'm using jQuery to call the page method.
private readonly ICatalogBLL _catalogBLL = new CatalogBLL();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
_catalogBLL.GetSomething();
}
}
[WebMethod]
public static UpdateSomething(int i)
{
//Want to do as below. But can't call it from a static method.
_catalogBLL.UpdateSomething();
}
UPDATE
If I call it as said by John Saunders, won't it use the same instance for requests from different users as it is within a static method?
You can't. The page method is static. Your _catalogBLL is an instance member.
However, since you create a new instance of CatalogBLL on every request, why not do so once more?
[WebMethod]
public static UpdateSomething(int i)
{
CatalogBLL catalogBLL = new CatalogBLL();
catalogBLL.UpdateSomething();
}
You can't call because pagemethods are static...
A static method is simply one that is disassociated from any instance of its containing class. The more common alternative is an instance method, which is a method whose result is dependent on the state of a particular instance of the class it belongs to.
Look at John saunder's answer..
We have developed a number of ASP.Net server controls and we need to test them. I want to instantiate a control, set some properties, call CreateChildControls and test the control-hierarchy.
I run into a number of problems:
The controls rely on HttpContext
CreateChildControls is private
Even adding a single child control to the controls collection calls the ResolveAdapter() method which relies on HttpContext.
How can I get around this?
p.s. I do not wish to test the controls on a page (!).
It sounds a lot like you don't care about the actual rendering of the control at all, but rather the logic contained within the control. For that I would suggest that you have another problem besides the inability to test the control outside the HttpContext.
If the logic only pertains to the control, then you should trust the framework to do it's job, and drop the control on a page to see if it works properly. If the logic you are attempting to test is business logic, then you need to refactor.
Pull out the business logic into a seperate Project/Dll somewhere, and think about implementing a MVP pattern with your server control. You don't have to go with a big heavy framework like WCSF either. Conceptually you can implement this with little effort.
Create an interface that represents the values on your view:
public interface IOrderView
{
Int32 ID{get; set;}
String Name{get; set;}
List<Item> Items {set;}
}
Once this is defined, you need a presenter that exercises this view:
public class OrderPresenter
{
public IOrderView View {get; set;}
public void InitializeView()
{
//Stuff that only happens when the page loads the first time
//This is only for an example:
var order = Orders.GetOrder(custId);
View.ID = order.ID;
View.Name = order.Name;
View.Items = order.Items;
}
public void LoadView()
{
//Stuff that happens every page load
}
}
Now your server control can implement this interface, and initialize itself with the OrderPresenter
public class OrderControl: Panel, IOrderView
{
private OrderPresenter Presenter{get; set;}
public OrderControl()
{
//Create new presenter and initialize View with reference
// to ourselves
Presenter = new OrderPresenter{View = this;}
}
protected override void OnLoad(EventArgs e)
{
if(Page.IsPostback)
{
_presenter.InitializeView();
}
_presenter.LoadView();
//Other normal onload stuff here...
}
//Now for the interface stuff
public Int32 ID
{
get{ return Int32.Parse(lblOrderId.Text); }
set{ lblOrderId.Text = value.ToString(); }
}
public String Name
{
get{ return lblOrderName.Text; }
set{ lblOrderName.Text = value; }
}
public List<Item> Items
{
set
{
gvItems.DataSource = value;
gvItems.DataBind();
}
}
}
And there you have it! You should be able to write unit tests against the OrderPresenter now using a stubbed out View. No HttpContext required, and you have cleaner seperation of concerns.
If you already have all your business logic seperated out then I appologize, but I can't think of any other reason to test a server control outside the ASP.Net runtime besides needing to verify actual business logic. If this is the case, then I would highly encourage you to refactor now before you realize the maintenance nightmare this will eventually cause via Leaky Abstractions.