Re: Master-Details binding of 2 related tables - WPF Discussion Boards

31-Aug-11 2:29

Hi!

Please help me to solve the problem:

I got DataSet, which contains 2 DataTables:
Categories (CategoryID, CategoryName)
Products(ProductID, CategoryID, Name)

These tables are linked using DataRelation by CategoryID key.
So, each product has category.

I got TreeView bound to DataSet.Tables["Categories"] - no problem here. Category names are displayed correctly as tree view items(having DisplayMemberPath=CategoryName)

And I got ListView.
So, I need to show Products in this ListView, that contains only the products of category selected in TreeView.

I don't know how to bind. Could you please help me?

Thanks!

Wayne Gaylard31-Aug-11 4:32

31-Aug-11 4:32

Personally, I think you are going about things the wrong way. When it comes to WPF, as I told you before, using datasets and trying to bind to them is seriously a PITA. For a start, I would create 2 classes, one for Products and one for Categories. These can be really basic. The Category class should have a property that returns a List of Products. Then I would have another class (call it a viewmodel if you will) that would implement the INotifyPropertyChanged[^] Interface. This viewmodel need only have 2 properties, one which returns an ObservableCollection of Categories, call it Categories(to be original), and another that returns a specific Category (call it SelectedCategory). These properties should call your NotifyPropertyChanged event handler whenever they are changed. The viewmodel should also be able to populate the collection of categories, either from a database or some other source, or it could be populated in the constructor. Then in your Window/UserControl constructor, all you need to do is create an instance of the viewmodel class, and set the Window/UserControl's datacontext to the instance (this can be done in the constructor). In your XAML, you set up 2 ListViews. The first ListView should have it's ItemsSource property set to bind to the Categories property of the view model. The second ListView, the one with 2 columns for each property of the product, should have it's ItemsSource bound to the SelectedCategory's Products Property, with the first column bound to the product Id, and the second Column bound to the Name. And that's it, Simples.

Doing things this way, will make your life so easier. If you have any problems with implementing this, I will try and help if I can.

Live for today. Plan for tomorrow. Party tonight!

bitwise.csc31-Aug-11 4:59

31-Aug-11 4:59

Wayne, firstly thank you so much for your efforts.

Seriously, I would never thought that using DataSets in WPF projects is not the best solution.
So, by now a got such code:

public DataSet GetDataSet()
 {
 string queryCatStr = @"SELECT * FROM [Category]";
 string queryProdStr = @"SELECT * FROM [Products]";

 DataSet ds = new DataSet();

 SQLConnection dbConn = new SQLConnection("conn_str"))
 dbConn.Open(); 
 SQLCommand cmd = new SQLCommand(dbConn);

 cmd.CommandText = queryCatStr;
 SQLDataAdapter da = new SQLDataAdapter(cmd);
 da.Fill(ds, "Categories");

 cmd.CommandText = queryProdStr;
 da.Fill(ds, "Products");

 DataRelation drCat2Prod = new DataRelation("Cat2Prod", ds.Tables["categories"].Columns["CategoryID"], ds.Tables["Products"].Columns["CategoryID"]);
 ds.Relations.Add(drCat2Prod);
 
 return ds;
 }


 private void Window_Loaded(object sender, RoutedEventArgs e)
 {
 ds = GetDataSet();
 this.DataContext = ds.Tables["Category"];
 this.treeCategories.DisplayMemberPath = "CategoryName";
 }

HTML

<TreeView x:Name="treeCategories" ItemsSource="{Binding}" />
...

<ListView x:Name="lstProducts" IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding Cat2Prod}" />

And now I just can't understand why this binding doesn't work as I expected - ListView contains products only for the first category and doesn't update contents when user selects another item in TreeView.

If I used ObservableCollection as a data source for the application, I would take care about initialization and synchronizing objects in the collection with data base. But ADO cand do it behind the scene as I think.

Even If I tried to init ObservableCollection of CategoryObjects with ProductsList contained in each one, I would make as many SQL queries to DB as many Categories I got in CategoriesTable.
Moreover, I should keep Data Base up-to-date, updating it manually. It seems to me this is not a good solution for me. But may be I'm wrong.

Pete O'Hanlon31-Aug-11 5:15

Pete O'Hanlon

31-Aug-11 5:15

This is exactly the type of scenario that you should be looking into the Entity Framework for. Using a DataSet to bind to complex items such as a TreeView is an overly complicated task, doesn't play well with the binding notification mechanism, and actually has a poor runtime performance.

Forgive your enemies - it messes with their heads

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bitwise.csc31-Aug-11 5:21

Navigate in Frame from code

31-Aug-11 5:21

Thanks, Pete.
I haven't heard about it before.
I would be glad If you know some code examples similar for my task.

The main task for me is just make the code of classic ADO.NET work as expected. Possibke overhead is not a problem by now.

yesu prakash30-Aug-11 19:34

yesu prakash

30-Aug-11 19:34

Hi,
How can i navigate to another page in a frame from code behind.

ex: I have a navigate frame, when i click on a link button from outside navigate frame i need to navigate it to another page by writing code behind.
i try ..
ContentFrame.UriMapper.MapUri(new Uri(@"/EmployeeList.xaml"));
ContentFrame.Source = new Uri("/EmployeeList.xaml");

in the click event. error i get is

Microsoft JScript runtime error: Unhandled Error in Silverlight Application Invalid URI: The format of the URI could not be determined. at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
at System.Uri..ctor(String uriString)
at HRMS.MainPage.Menu_MenuItemClicked(Object sender, EventArgs e)
at SilverlightMenu.Library.Menu.gridLevel2_MouseLeftButtonUp(Object sender, MouseButtonEventArgs e)
at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)

Thankyou,
YPKI

Re: Navigate in Frame from code

Mycroft Holmes30-Aug-11 22:24

Mycroft Holmes

30-Aug-11 22:24

I have a static method that I call from any forms code behind. The default frame is the main navigation frame but I can pass in a frame if required

public static void NavigateTo(string sViewName)
{
	//Get the content frame from the main page via the application
	Frame oFR = (Application.Current.RootVisual as FrameworkElement).FindName("MainContent") as Frame;
	NavigateTo(oFR,sViewName);
}

public static void NavigateTo(Frame oFR, string sViewName)
{	
	if(!sViewName.StartsWith("/"))
	{sViewName = string.Format("/{0}",sViewName);}
		oFR.Navigate(new Uri(sViewName, UriKind.Relative));
}

And call it passing in the name of the view. The view is in the app.xaml of course. Do some research into Silverlight navigation projects.

gUI.NavigateTo(sURL);

Never underestimate the power of human stupidity
RAH

Data binding model: "Main->Details"

bitwise.csc29-Aug-11 3:14

29-Aug-11 3:14

Hi!

Please help me to solve the problem:

I got DataSet, which contains 2 DataTables:
Categories (CategoryID, CategoryName)
Products(ProductID, CategoryID, Name)

These tables are linked using DataRelation by CategoryID key.
So, each product has category.

I got TreeView bound to DataSet.Tables["Categories"] - no problem here. Category names are displayed correctly as tree view items(having DisplayMemberPath=CategoryName)

And I got DataGridView (imported from Windows Forms using WindowsFormsHost control).
So, I need to show Products table in this DataGridView, that contains only the products of category selected in TreeView.

I don't know how to bind DataGridView in this case. Could you please help me?

Thanks!

Wayne Gaylard29-Aug-11 3:24

29-Aug-11 3:24

Is there any particular reason that you are using the WinForms DataGridView? WPF has got a DataGrid, which is fully compatible with data binding. You could have a property(call it SelectedCategory) in your viewmodel/codebehind which holds the selected category(bound to the SelectedItem property of the TreeView), and bind the DataGrid to SelectedCategory.Products. You then create a DataTemplate for the DataGrid which will show the particular properties of each product such as name, retail price etc.

Live for today. Plan for tomorrow. Party tonight!

bitwise.csc29-Aug-11 3:30

29-Aug-11 3:30

Is there any particular reason that you are using the WinForms DataGridView? WPF has got a DataGrid, which is fully compatible with data binding.

See, I have strong restriction for my project to run under .NET version 3.5
It has no DataGrid control included. That's why I have to use DataGridView.

Wayne Gaylard29-Aug-11 3:42

Re: Data binding model: "Main->Details" [modified]

29-Aug-11 3:42

The WPF Toolkit[^] on CodePlex has a DataGrid which is compatible with .Net 3.5. If you don't like that option, the WPF ListView can be used with the View property set to Grid, and with some styling can be a very good alternative to a 'proper' DataGrid. Personally, I would use one of those options as opposed to the WinForms DataGridView.

Live for today. Plan for tomorrow. Party tonight!

bitwise.csc29-Aug-11 3:51

29-Aug-11 3:51

Thanks a lot, Wayne.
Unfortunately I can't use any additional install packages for deployment. I'm just targeted on .NET 3.5 I will check the way to use ListView!

If someone has further ideas please welcome!

modified on Monday, August 29, 2011 10:10 AM

bitwise.csc29-Aug-11 11:14

29-Aug-11 11:14

Unfortunately I couldn't find the way how to bind ListView to DataSet using the current selection of TreeView. Could you please provide simple example?

Wayne Gaylard29-Aug-11 22:03