WPF/VB.NET Memory Leaks - reproducible, when creating multiple RichText controls in a WPF form. Grrrrr! - WPF Discussion Boards

That does indeed seem like the best solution, but it still involves services - not direct db access, which I would have preferred...

I still don't see why a Silverlight app running on the client can't access a db directly using ado when basically all other types can (winforms, webforms and even WCF apps I'm told in another post in this thread)... Bummer. But my guess is that it's done that way to keep the size of the runtime to an absolute minimum.

I'll have a look at your article, though, and I think I'll be going with this solution in the end (if I don't decide against Silverlight all together).

Beidh ceol, caint agus craic againn - Seán Bán Breathnach
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Don't tell my folks I'm a computer programmer - They think I'm a piano player in a cat house...
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Da mihi sis crustum Etruscum cum omnibus in eo!
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Everybody is ignorant, only on different subjects - Will Rogers, 1924

Silverlight does not support all the protocols that WCF have, so to create a WCF service that can be used by Silverlight , you need to use BasicHTTP. So if you look at your web forms , you will see that the controls have the "runatserver" property , that is why you could use direct ado.net.

But in silverlight everything is fully on the client side. the nice thing about silverlight comparing it to win-forms and asp.net is that there are other things that you don't need to worry about , things like the post back , cross browser compatibility and it can run as a web app and as a win form like app(Out-of browser). my java-script skills are not that good that is why i prefer to place a control at a certain location of a form and expect to find it there when i run my app. its a matter of preference.

Vuyiswa Maseko,

Spoted in Daniweb-- Sorry to rant. I hate websites. They are just wierd. They don't behave like normal code.

C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.com
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/

I haven't seen this answer, so here's my attempt.

I'm not a Silverlight expert either, but I think Silverlight cannot access ADO.Net directly, because it is an application running ijn Internet Explorer, which is more or less a sandbox limiting possebilities. The reason why Asp.Net or WCF can access the database is because both run on the server (ASP.net does little more then generating text which the browser interprets as HTML).

in short, I think Silverlight is limited here because it runs inside the browser. Possibly there is a workaround...

V.

Hello,

I have a listbox of "users", when one is selected I want to display two listboxes: one containing the "reports" associated to the user, the other one the "other" reports. And buttons to move reports between the two listboxes. Very common scenario.

Users and reports are stored in a database accessed via ADO.NET. I have the following tables:

User: ReportingUser varchar(20) primary key
Reporting: ReportingCode varchar(20) primary key, ReportingName varchar(20)
ReportingUser: ReportingUser varchar(20), ReportingCode varchar(20)

I imported the tables in designer and added two Relations:
User_ReportingUser: ReportingUser.ReportingUser *->1 User.ReportingUser
FK_Reporting_ReportingUser: ReportingUser.ReportingCode *->1 Reporting.ReportingCode

The first relation is what my window edits. The second if for fishing the report name and display that instead of the report code.

I have the following XAML:

<ListBox Name="listBoxUsers" IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding}" DisplayMemberPath="ReportingUser" />
<ListBox Grid.Row="1" Name="listBoxSelectedReporting" ItemsSource="{Binding User_ReportingUser}"
   DisplayMemberPath="Row.ReportingRow.ReportingName" />

...and Window_Loaded handler:

userAdapter = new UserTableAdapter();
reportingUserAdapter = new ReportingUserTableAdapter();
reportingTableAdapter = new ReportingTableAdapter();
dataset = new DNLMHDataSet();
userAdapter.Fill(dataset.User);
reportingTableAdapter.Fill(dataset.Reporting);
reportingUserAdapter.Fill(dataset.ReportingUser);
listBoxUsers.DataContext = dataset.User;
listBoxSelectedReporting.DataContext = dataset.User;

It's amazing to see that this suffices to give me master/detail behavior. My first question is: why does this work? Is there a compact explanation of this somewhere ?

I googled around and did find information, e.g. about IsSynchronizedWithCurrentItem, but it's not enough to enlighten me. Where is the "current item" stored ? In listBoxUsers ? How is the other listbox aware that the current item has changed ? The "content" of the User_ReportingUser Relation is parameterized by the currently selected user. How does the ItemsSource of the Report listbox know which user is current ? What's the activity diagram ?

Also, now I would like to implement the reports that are not selected for the current user. First I tried to create a query for that but the designer only allows SQL code that returns a single value. So I created a TableAdapter with the following SQL:

SELECT     ReportingCode, ReportingName
FROM         Reporting AS r
WHERE     (NOT EXISTS (
  SELECT ReportingCode
  FROM ReportingUser AS u
  WHERE(ReportingCode = r.ReportingCode) AND (ReportingUser = @ReportingUser)))

Here again the "content" of the table is parameterized by the same ReportingUser. How can I make the listbox for the non-selected reports coordinate automagically with the User master control ?

Hello,

How to bind List of objects in the button's CommandParameter in Xaml.

Thanks in adv..

Without looking at your code it is impossible to tell. But you could try relative binding or element name binding. These would be able to pass the collection of objects to your view model code.

The funniest thing about this particular signature is that by the time you realise it doesn't say anything it's too late to stop reading it.

In silverlight, drawing a line, if zooming in it,the polyline will be deformation,a moving line will appear.

You can use bingmap for example.

MapPolyline line = new MapPolyline();
            line.Stroke = new SolidColorBrush( Colors.Brown );
            line.StrokeThickness = 3;
            line.Locations = new LocationCollection();
            double lon = 114.219340787406, lat = 23.0518068854053;
            for ( int i = 0 ; i < 100 ; i++ )
            {
                int k = 1;
                if ( i % 2 == 0 )
                {
                    k = -1;
                }
                Location location = new Location( lat + k * 0.03, lon + 0.02 * i );
                line.Locations.Add( location );
            }

            this.myMapLayer.Children.Add( line );

When you move the map amplifier to level 18th , moves to the line polyline, it will appear a line. And this line will move where map change.

How to solve this problem.

(Code below)

I create 200 RichTextBoxes into a collection on form load, so that I can populate a grid with them when the form is clicked.

When you click the form, it populates TestGrid with the 200 RichTextBoxes, one per row.

That part works fine, but whenever I change anything about the RichTextBoxes, like Background brush, or text, the memory just keeps on growing, each time I populate grid. I'm not ADDING text, it's the same text, every time. Nothing changes at all between grid refills.

Please, I implore you to copy this XAML and code to a new WPF project, and click on the form repeatedly, as you monitor task manager.

It's even worse if you change more properties other than text - like it can get to be 10 MB mem usage growth per refill.

I've looked on the web, to no avail. Makes no ******* sense. WTF | :WTF:

WPF is great, but: Mad | :mad:

I've read from a lot of angry people on web about WPF memory probs. None of them talked about this scenario, though, unfortunately.

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Grid>
        <ScrollViewer HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Name="ScrollViewer1">
            <Grid  Name="TestGrid">
           </Grid>
        </ScrollViewer>
    </Grid>
</Window>

Imports System.Windows.Documents

Class MainWindow

    Dim Riches As New Collection
    Dim WorkRange As TextRange

    Private Sub MainWindow_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded

        'HERE I'M FILLING THE RICHES COLLECTION WITH 200 RICHTEXTBOXES

        Dim RichRange As Long, NewRich As RichTextBox
        For RichRange = 1 To 200
            NewRich = New RichTextBox
            Riches.Add(NewRich)
        Next

    End Sub


    Private Sub MainWindow_PreviewMouseDown(ByVal sender As Object, ByVal e As System.Windows.Input.MouseButtonEventArgs) Handles Me.PreviewMouseDown

        Me.Title = "Start"

        With TestGrid
            .RowDefinitions.Clear()
            .Children.Clear()

            Dim RowRange As Long
            For RowRange = 1 To 200
                .RowDefinitions.Add(New RowDefinition)

                Dim HeaderCell As RichTextBox
                HeaderCell = Riches(RowRange)

                With HeaderCell


                    WorkRange = New TextRange(.Document.ContentStart, .Document.ContentEnd)
                    WorkRange.Text = "Poo " & CStr(RowRange)

                End With

                .Children.Add(HeaderCell)
                .SetRow(HeaderCell, RowRange - 1)
                .SetColumn(HeaderCell, 0)

            Next
        End With

        GC.Collect()

        Me.Title = "Stop"

    End Sub
End Class

If you're going to help me out and test this yourself, you can try commentizing the 2 lines of code that changes the text:

WorkRange = New TextRange(.Document.ContentStart, .Document.ContentEnd)
WorkRange.Text = "Poo " & CStr(RowRange)

By removing those two lines, no more memory growth will be visible in task manager.

Thanks a bunch!

Hello To All,

I am new to MVVM with Silverlight.
MyTestView --> View (Button, Grid)
MyTestViewModel --> ViewModel (WCF Service Methods)

In my button call I have assigned the DataContext. I have to fill grid with the data that have been returned from the service call in the same click event in the View's code behind.

Any help regarding this will be greatly appreciated..

Thanks in adv...

As in your other post, you are misunderstanding MVVM. All your code belongs in the ViewModel, not in the code behind (there are a few exceptions). You should not be assigning DataContext in button handlers. It should be set once using something like the view locator pattern. Everything that the View gets from the ViewModel is done with data binding, not code in the code behind.

Hi..

Thanks for the reply.
But I have situation for getting search criteria from the page and perform the operation in the button click event based on passing the search criteria to the view model.
So, How can I get view's control value in the viewmodel?
Can u pls give a hint about how to overcome such type of situations?

Thanks..

The search criteria should be bound to a property on the VM. You then have the data in the VM, responding to the event (click the search or the key up/down) need to be handled.

Never underestimate the power of human stupidity
RAH

Set the view's datacontext to the view model.
You could then apply commands to handle the button command click in the view model.

The funniest thing about this particular signature is that by the time you realise it doesn't say anything it's too late to stop reading it.

Hello to All,

Can anyone can help me get data from the ViewModel(DataContext of the page) in Page's Code behind using MVVM architecture.

Thanks in Adv..

this.LayoutRoot.DataContext

This assumes the layoutroot has the data context assigned (otherwise just this.datacontext). You will also need to cast the datacontext back to your viewmodel

Never underestimate the power of human stupidity
RAH

You should be setting the Datacontext of the page to the viewmodel somewhere if you are implementing MVVM correctly.

The funniest thing about this particular signature is that by the time you realise it doesn't say anything it's too late to stop reading it.

One of the aspects of MVVM is that you don't have any code behind. The only thing thats "allowed" in the code behind is manipulating visuals. The fact that you want to interact with the ViewModel from the code behind is definitely wrong.

Hi,

can any one tell me how should i change the display of a combobox as a hyperlink, and when clicked on hyperlink it has to replace it by the combobox in the same place and display combobox item in the dropdown manner attached to the hyperlink...

This really sounds ugly, bleh

Use a datatemplate to create the comboboxitem with the HL
Create a second combo with standard formatting

You then have a number of events that need to be managed.

Click event on the HL
Do what you need with the data and set a property that makes the original CB collapsed and a second CB visible.

How you recover back to the original HL combo is a mystery you will need to unravel.

Never underestimate the power of human stupidity
RAH

Yeah man, like Mycroft said... randomly changing a hyperlink <-> combobox is UGLY and not a very good UI IMO. Controls shouldn't randomly change types. It might make sense in your head, but it wouldn't make sense to a user.

I don't like the behavior of the datagrid when using the celltemplate and cell editting template elements of WPF.

<DataGridTemplateColumn
                    Header="Street Name"
                    Width="77">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock
                                Text="{Binding street}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                    <DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <TextBox
                                Text="{Binding street, ValidatesOnDataErrors=True,UpdateSourceTrigger=PropertyChanged}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellEditingTemplate>
                </DataGridTemplateColumn>

You have to double tab to access the editing feature of the cell, you have to double click to edit it and it is when you use a combobox it gets even worse. Has anyone managed to make the DG usable? As it stands right now I need it, but I am almost embarrassed to release software with such erratic behavior. Does anyone have pointers on making this thing useful? My major issues are the double clicking issue with cellediting / celltemplate and the usability of a drop down:

<DataGridTemplateColumn
                    Header="State"
                    Width="60">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock
                                Text="{Binding PropertyState.name}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                    <DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <ComboBox
                                ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}},Path=DataContext.PropertyStates, ValidatesOnDataErrors=True,UpdateSourceTrigger=PropertyChanged}"
                                DisplayMemberPath="name"
                                SelectedValuePath="id"
                                SelectedValue="{Binding stateId}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellEditingTemplate>
                </DataGridTemplateColumn>

If this thing is a pain, is there a useful method of validating the datagrid without using the celltemplate / celleditingtemplate?

Cheers, --EA

Thats probably just how the control works by default. If you don't like the behavior, you can always change it Smile | :)

. I'm guessing you want a single click to go into edit mode? My first approach would be to catch the single click and if the cell contains a control, put it into edit mode. Lots and lots of gotchas though. A text box should go into edit mode directly on the first click, but a combobox should only go into edit mode if you click the edit portion. I don't think it should go into edit mode if you click the drop down button. Or maybe it should? You need to play with it. You'll probably have to special case a few of the control types to get what you want. I.e. if the control is a text box do this, if you the control is a combobox, do this instead. Another gotcha I can see is if you catch the click too early, you'll "break" the controls. For example, a push button should be executed on release, not on click. The click on a button just gives it focus and captures mouse focus so you can mouse off the button with the mouse still pressed and come back and it'll get pressed again, etc.

Having read SH01s answer and the fact that you rarely see this type of question (editing in a SL datagrid) I feel it reinforces a design decision I have made and advocate.

NEVER USE A LIST CONTROL AS AN EDIT CONTROL

I apply the same rule to winforms, 99% of the time I use a dedicated edit form/control to do editing, either pop a dialog or have a dedicated details control on the form. The ONLY exception I allow is when the user need to edit 1 (and only 1) single cell of either textbox or checkbox.

The combobox in SL is such a PITA I would never even consider using it in a gridview. Change you design!

Never underestimate the power of human stupidity
RAH

So in this instance of a workspace based WPF desktop application would you consider a master / details layout in order to edit a row as opposed to in row editing? I fail to see why it would be discouraged to use a control that has editing functionality to edit, especially when it improves the user experience when working as intended.

Still, as it is not working as intended it is what it is. It would have been much easier for the user to allow in place editing.

Thanks for the insight, though.

Cheers, --EA

I don't really agree with Mycroft that you shouldn't allow in place row editing. Thats silly. Thats EXACTLY what a data grid is for. If you go into Excel and can't edit cells, you would be thouroughly confused. Just do what I suggested in my other response and tweak the control to your liking.