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ItemSource Binding happens twice

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GridView

This is a migrated thread and some comments may be shown as answers.

Jaco De Villiers asked on 29 Dec 2010, 08:32 AM

Hi,

I am using the RadGridView in an MVVM project. The ViewModel has a property ObservableCollection<T> to which the ItemSource property is bound. When a I place a break point in the ViewModel property get, then it is accessed twice. Am I doing something wrong? The XAML is below. Also, what is the best practice when loading data using a pager and ensuring only page size is loaded from the database and not all records (e.g. Take(20));

Regards
Jaco

<Window x:Class="DBAppBestPractice.MainWindow"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

xmlns:Examples="clr-namespace:DBAppBestPractice"

xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"

xmlns:telerikGrid="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"

x:Name="root"

DataContext="{Binding Main, Source={StaticResource Locator}}"

>

<Window.Resources>

<ResourceDictionary>

<ResourceDictionary.MergedDictionaries>

<ResourceDictionary Source="Skins/MainSkin.xaml" />

</ResourceDictionary.MergedDictionaries>

</ResourceDictionary>

</Window.Resources>

<Grid>

<Grid.RowDefinitions>

<RowDefinition Height="Auto" />

<RowDefinition />

</Grid.RowDefinitions>

<Border Grid.RowSpan="2" />

<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,5,0,0">

<telerik:RadButton Width="150" Content="Delete selected rows" Margin="0,0,5,0"

Command="telerikGrid:RadGridViewCommands.Delete" CommandTarget="{Binding ElementName=RadGridView1}" />

<telerik:RadButton Width="150" Content="Add new row" Margin="0,0,5,0"

Command="telerikGrid:RadGridViewCommands.BeginInsert" CommandTarget="{Binding ElementName=RadGridView1}" />

<telerik:RadButton Width="150" Content="Save insert/edit" Margin="0,0,5,0"

Command="telerikGrid:RadGridViewCommands.CommitEdit" CommandTarget="{Binding ElementName=RadGridView1}" />

<telerik:RadButton Width="150" Content="Cancel insert/edit"

Command="telerikGrid:RadGridViewCommands.CancelRowEdit" CommandTarget="{Binding ElementName=RadGridView1}" />

</StackPanel>

<telerik:RadGridView x:Name="RadGridView1"

ItemsSource="{Binding LoadedSuppliers}"

SelectionMode="Extended"

AutoGenerateColumns="False"

Margin="0,5,0,0"

Grid.Row="1"

ActionOnLostFocus="None" RowEditEnded="RadGridView1_RowEditEnded" Deleted="RadGridView1_Deleted">

<telerik:RadGridView.Columns>

<telerik:GridViewColumn>

<telerik:GridViewColumn.CellTemplate>

<DataTemplate>

<telerik:RadButton Content="Delete" Command="telerikGrid:RadGridViewCommands.Delete" CommandParameter="{Binding}" />

</DataTemplate>

</telerik:GridViewColumn.CellTemplate>

</telerik:GridViewColumn>

<telerik:GridViewDataColumn DataMemberBinding="{Binding Id}" Header="Id" IsReadOnly="True" />

<telerik:GridViewDataColumn DataMemberBinding="{Binding Name}" Header="Name" />

<telerik:GridViewDataColumn DataMemberBinding="{Binding Description}" Header="Description" />

</telerik:RadGridView.Columns>

</telerik:RadGridView>

</Grid>

</Window>

2 Answers, 1 is accepted

answered on 29 Dec 2010, 10:35 AM

RadGridView_WPF_AR_2.zip

Hello Jaco De Villiers,

I could not reproduce the problem with the double invokes of the getter. Find attached a sample project.

You can also check the Unbound Mode of RadDataPager.

Greetings,
Veselin Vasilev
the Telerik team

Browse the videos here>> to help you get started with RadControls for WPF