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No it is a serious question - scenario...
WCF with a single data access class,
A data service class for each table/view in the database. This maps a datatable to the model
A model class for each table/view in the database to be passed in a List<> to the client - implements OnPropertyChanged
WPF client that uses the WCF and retrieves List<> of the models. The client is set to reuse the WCF objects (Models)
This means I do not have to remap the WCF models to client models, however chasing down a potential memory leak I find I have multiple copies of the models in memory. I have 1 particular view with 35 master lists (servicing comboboxes) and another 7 lists used for multi selects over 2 Tabs. Fricking nightmare! This view can take between 2 and 12 seconds to load and I'm attempting to find out why.
So the question should I be passing POCO objects from the WCF and converting them to local models with the OPC implementation?
Never underestimate the power of human stupidity
RAH
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Why pass a POCO when only a scalar might be needed?
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I pass all manner of objects, including scalar values. The point is that when I pass a list it is a List<> of a class with the OnPropertyChanged events included rather than a List<> of POCO objects. Is this likely to cause memory leaks?
Never underestimate the power of human stupidity
RAH
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The OnPropertyChanged handler is null until a presenter subscribes to it. Can't think of any other references that might cause a problem.
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Tracked the problem down to the binding the selected object to the form, just too many comboboxes, the object has over 50 fields and binds to 30 comboboxes on the one view.
I gave them a couple of options, split the view or change to popups instead of combo boxes. The decided to live with the issue - bloody users.
Never underestimate the power of human stupidity
RAH
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I used to "virtualize" these clumsy scenarios (combo boxes) into windows with data base smart grids.
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How did you pop the windows, button or mouse over?
This is another option I am considering as there is a lot of looking but not a great deal of modification after the object is created.
Never underestimate the power of human stupidity
RAH
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I'd pop the window on demand (e.g. F4 or a right-mouse click while a data-entry field has focus) or on trying to exit the field after typing an invalid entry. The intent was to minimize key strokes and mouse moves and maintain flow.
modified 27-Nov-15 20:37pm.
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<ListView x:Name="lvBookings" VirtualizingStackPanel.IsVirtualizing="True" MinHeight="300" MinWidth="850" ItemsSource="{Binding ListViewItemsCollections}" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2">
<ListView.View>
<GridView AllowsColumnReorder="False">
<GridViewColumn Header="Venue" Width="100" DisplayMemberBinding="{Binding Venue}"/>
<GridViewColumn Header="Date" Width="100" DisplayMemberBinding="{Binding Date}"/>
<GridViewColumn Header="Status" Width="100" DisplayMemberBinding="{Binding Status}"/>
<GridViewColumn Header="Duration" Width="100" DisplayMemberBinding="{Binding Duration}"/>
<GridViewColumn Header="TimeIn" Width="100" DisplayMemberBinding="{Binding TimeIn}"/>
<GridViewColumn Header="TimeOut" Width="100" DisplayMemberBinding="{Binding TimeOut}"/>
<GridViewColumn Header="Progress" Width="100">
<GridViewColumn.CellTemplate>
<DataTemplate>
<ProgressBar Name="pbDuration" Value="{Binding ProgressValue}" Minimum="0" Maximum="{Binding MaxValue}" Width="100"/>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
</GridView>
</ListView.View>
</ListView>
modified 22-Nov-15 7:40am.
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It would depend, I believe, on how you want to use it. If you are trying to set its visible property, for example, you might try the "Path=" or the ElementName= syntax. I am pretty new to WPF but accessing child controls of the element tree ought to be the same as when you need to bind to another element.
I hope this helps. As I said, I am sort of a beginner.
Joey
Joseph M. Morgan
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So I'm learning about Routed Events. I just found this[^] excellent blog post.
I understand what it does, but why not just do this:
public delegate void ButtonWasClickedEventHandler();
public event ButtonWasClickedEventHandler ButtonWasClicked;
private void raiseButtonWasClicked()
{
if (ButtonWasClicked != null)
{
ButtonWasClicked();
}
}
and then in the parent control:
<local:ChildControl Margin="61,87,108,95"
ButtonWasClicked="ChildControl_ButtonWasClicked"/>
and
private void ChildControl_ButtonWasClicked()
{
}
Basically, I don't see the point of the routed event. A Standard event works fine.
If it's not broken, fix it until it is
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Hi,
I want to change silverlight 4 datepicker format as 'dd/MM/yyyy' in one page only. I tried below code
Thread.CurrentThread.CurrentCulture = (CultureInfo)Thread.CurrentThread.CurrentCulture.Clone();
Thread.CurrentThread.CurrentCulture = (CultureInfo)Thread.CurrentThread.CurrentCulture.Clone();
Thread.CurrentThread.CurrentCulture.DateTimeFormat.ShortDatePattern = "dd/MM/yyyy";
But It changes format in whole silverlight application. I want datepicker change format in one silverlight page only.
Please give me solution.
Thanks.
Regards,
Suchita Gorivale
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You need to include Stringformat in the binding xaml.
{Binding YourDateField, StringFormat='dd/MM/yyyy'}
Take a read of this article[^]
Never underestimate the power of human stupidity
RAH
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I want my button to be enable only when one item in listbox is checked else disable the button. how to achieve this? Any help please
<ListBox Name="listBoxDraftVersions" Height="200" Width="250" Margin="3" ItemsSource="{Binding DraftList}">
<ListBox.ItemTemplate>
<DataTemplate>
<Border x:Name="TheBorder" BorderBrush="Gray" BorderThickness="1" Padding="4" CornerRadius="4" Margin="2">
<CheckBox Name="radioButZone" Content="{Binding DraftName}" IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBoxItem}}, Path=IsSelected}"></CheckBox>
<Border.Background>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="AliceBlue" Offset="0.15" />
<GradientStop Color="White" Offset="0.85" />
<GradientStop Color="Lavender" Offset="1" />
</LinearGradientBrush>
</Border.Background>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button Content="Load" IsDefault="True" x:Name="btnLoad" Style="{StaticResource MetroButton}" Click="btnLoad_Click" />
i tried
IsEnabled="{Binding ElementName=listBoxDraftVersions, Path=IsSelected}" not working
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Add a DataTrigger to your Button; e.g.
<Button Content="Load"
IsDefault="True"
x:Name="btnLoad"
Click="btnLoad_Click">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=listBoxDraftVersions, Path=SelectedItems.Count}"
Value="0">
<Setter Property="IsEnabled"
Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
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Hi Gerry,
Thanks for your quick reply , same thing is happening if i use
IsEnabled="{Binding ElementName=listBoxDraftVersions, Path=SelectedItems.Count}" on button.
But i want button to be enabled when only 1 checkboox is checked else it should be diabled if >1 and <1
Thanks and Regards
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"IsEnabled" is a bool; simply trying to bind it to SelectedItems.Count (an int) is not going work.
You might be able to use a "converter" in there ...
(Or just change the trigger to "enable" the button if the "count" is 1; using a default of "not enabled").
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Hi Gregg,
In that case i am not able to select multiple checkboxes. i want to select multiple checkboxes also but using this cannnot select multiple only one is getting checked at one time.
Thanks
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To select multiple items, the "SelectionMode" for the ListBox should be set to "Multiple".
If you are going to ignore the "built-in" selection logic of the ListBox and associated items, then you will have to use your own custom code.
Your approach is wrong.
Your are using checkboxes to "select" items in a listbox; instead, you should simply use the checkbox to "display" the "selected" status of a given item and use the built-in selection logic as it was intended.
(Gary, Larry, Gerald, George and now Gregg ... My level of visibility is now tracking in the minus range).
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I'm trying to bind the ListBoxItem's IsSelected property to a property called 'IsItemSelected' on my base entity.
<Style x:Key="listBoxItemContainerStyle"
TargetType="ListBoxItem">
<pre>
<Setter Property="IsSelected" Value="{Binding IsItemSelected}"/>
This isn't working. The selected item's IsItemSelected property is not being set.
What am I missing here?
Thanks
If it's not broken, fix it until it is
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A couple of ideas, first what is the listbox items source? Make sure that the object in the items source should have a boolean property "IsItemSelected" and that would be the property that you bind the value to, not the view model.
I made a sample object that had two properties, string Name and bool IsItemSelected
I added that to an observable collection (yourList) and then I define the ListBox and the container style as such
<ListBox ItemSource="{Binding yourList}" DisplayMemberPath="Name">
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="IsSelected"
Value="{Binding IsItemSelected}"/>
If this is not working then the fault might be in your view model, things to make sure are are you implementing INotifyPropertyChanged? Is your event set up correctly? If this is still not working and you would like to post your view model I would be happy to help.
Cheers!
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I have one datagrid, inside that datagrid have taken one combobox. I am trying to create the SelectionChanged event for this combobox but its not working. Below is the code:
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<StackPanel Orientation="Horizontal">
<cc:MyComboBox Name="ddlDepositMode" Width="150" ItemsSource="{Binding DataContext.ModeCollection, Mode=TwoWay, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}}" DisplayMemberPath="ModeName" SelectedValuePath="ModeId" IsSynchronizedWithCurrentItem="False" SelectedValue="{Binding Path=ModeId,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding Path=ModeName, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Padding="3,0,0,0">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<i:InvokeCommandAction Command="{Binding DataConext.ModeTypeCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</cc:MyComboBox>
</StackPanel>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
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Ashfaque Hussain wrote: DataConext.ModeTypeCommand
Shouldn't that be DataContext.ModeTypeCommand?
If it still doesn't work, check the Output window in Visual Studio for binding errors.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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I have taken checkbox on the header of the DataGrid, but Boolean property of IsChecked is binding.
<DataGridTemplateColumn.HeaderTemplate>
<DataTemplate>
<StackPanel>
<cc:MyCheckBox Width="30" IsChecked="{Binding Path=MyViewModel.IsAllSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" ></cc:MyCheckBox>
</StackPanel>
</DataTemplate>
</DataGridTemplateColumn.HeaderTemplate>
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