在我的项目中，我有一种行为来检测ScrollView在我的数据网格中的底部。
只有当数据从视图加载加载并且需要直接使用ScrollView时，他才能很好地工作。
有时我的数据可以第二次加载而不是。
我的行为
public class ScrollViewerMonitor
{
public static DependencyProperty AtEndCommandProperty
= DependencyProperty.RegisterAttached(
"AtEndCommand", typeof(ICommand),
typeof(ScrollViewerMonitor),
new PropertyMetadata(OnAtEndCommandChanged));
public static ICommand GetAtEndCommand(DependencyObject obj)
{
return (ICommand)obj.GetValue(AtEndCommandProperty);
}
public static void SetAtEndCommand(DependencyObject obj, ICommand value)
{
obj.SetValue(AtEndCommandProperty, value);
}
public static void OnAtEndCommandChanged(
DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement element = (FrameworkElement)d;
if (element != null)
{
element.Loaded -= element_Loaded;
element.Loaded += element_Loaded;
}
}
static void element_Loaded(object sender, RoutedEventArgs e)
{
FrameworkElement element = (FrameworkElement)sender;
element.Loaded -= element_Loaded;
ScrollViewer scrollViewer = FindChildOfType<ScrollViewer>(element);
if (scrollViewer == null)
{
return;
}
var dpd = DependencyPropertyDescriptor.FromProperty(ScrollViewer.VerticalOffsetProperty, typeof(ScrollViewer));
dpd.AddValueChanged(scrollViewer, delegate (object o, EventArgs args)
{
bool atBottom = scrollViewer.VerticalOffset
>= scrollViewer.ScrollableHeight;
if (atBottom)
{
var atEnd = GetAtEndCommand(element);
if (atEnd != null)
{
atEnd.Execute(null);
}
}
});
}
static T FindChildOfType<T>(DependencyObject root) where T : class
{
var queue = new Queue<DependencyObject>();
queue.Enqueue(root);
while (queue.Count > 0)
{
DependencyObject current = queue.Dequeue();
for (int i = VisualTreeHelper.GetChildrenCount(current) - 1; 0 <= i; i--)
{
var child = VisualTreeHelper.GetChild(current, i);
var typedChild = child as T;
if (typedChild != null)
{
return typedChild;
}
queue.Enqueue(child);
}
}
return null;
}
}
在我的XAML中
<D:DataGridTemplate x:Name="Datagrid" Behavior:ScrollViewerMonitor.AtEndCommand="{Binding LoadCommand,UpdateSourceTrigger=PropertyChanged}">
我希望即使在启动时没有出现滚动视图，行为也可以检测到滚动视图何时出现
此Datagrid不起作用：
<D:DataGridTemplate x:Name="Datagrid" Behavior:ScrollViewerMonitor.AtEndCommand="{Binding LoadCommand}" SelectedValue="{Binding SelectedID}" SelectedValuePath="Swmo_id" Grid.Column="0" Grid.Row="1" Grid.RowSpan="1" ItemsSource= "{Binding TypeMouvement, Converter={StaticResource TypeCollectionConverter},Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Grid.ColumnSpan="2" >
<!--"{Binding TypeMouvement, Converter={StaticResource TypeCollectionConverter}}"TypeMouvement-->
<DataGrid.Resources>
<Helper:BindingProxy x:Key="proxy" Data="{Binding}" />
</DataGrid.Resources>
<DataGrid.Columns>
<D:DataGridFirstColumn Visibility="{Binding Data.TypeMouvement, Converter={StaticResource FirstColumnConverter}, Source={StaticResource proxy}}"/>
<!--Mofi_Id-->
<DataGridTextColumn Header="N° Chrono" Width="Auto" Binding="{Binding Path=Mofi_Id, Converter={StaticResource GestionMouvementConverter}, ConverterParameter=Mofi_Id}">
<DataGridTextColumn.Visibility>
<MultiBinding Converter="{StaticResource ColumnTypeConverter}" Mode="TwoWay">
<MultiBinding.Bindings>
<Binding Path="Data.DataChampFinal[0].Cham_Order" Source="{StaticResource proxy}" />
<Binding Path="Data.TypeMouvement" Source="{StaticResource proxy}" />
</MultiBinding.Bindings>
</MultiBinding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<!--id-->
<DataGridTextColumn Header="ID" Binding="{Binding Path=Swmo_id}"
Visibility="{Binding Data.DataChampFinal[1].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<!--Visibility="{Binding Data.Swmo_id, Converter={StaticResource VisibleColumnConverter}, ConverterParameter=1, Source={StaticResource proxy} "{Binding coucou, Converter={StaticResource DisplayIndexOrder}, ConverterParameter=0}" DisplayIndex="{Binding Int10, Mode = TwoWay, FallbackValue = 1}" Visibility="{Binding Data.TypeMouvement, Converter={StaticResource ColumnTypeConverter}, Source={StaticResource proxy}}" /> -->
<DataGridTextColumn Header="Date de validation" Binding="{Binding Path=Mofi_Datefinal, Converter={StaticResource GestionMouvementConverter}, ConverterParameter=Mofi_Datefinal}">
<DataGridTextColumn.Visibility>
<MultiBinding Converter="{StaticResource ColumnTypeConverter}" Mode="TwoWay">
<MultiBinding.Bindings>
<Binding Path="Data.DataChampFinal[2].Cham_Order" Source="{StaticResource proxy}" />
<Binding Path="Data.TypeMouvement" Source="{StaticResource proxy}" />
</MultiBinding.Bindings>
</MultiBinding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Date du mouvement" Binding="{Binding Path=Mobr_Datemouv, Converter={StaticResource GestionMouvementConverter}, ConverterParameter=ConvertDateFR }"
Visibility="{Binding Data.DataChampFinal[3].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Date d'Entrée CM." Binding="{Binding Path=Mobr_Dateentreecm, Converter={StaticResource GestionMouvementConverter}, ConverterParameter=ConvertDateFR }"
Visibility="{Binding Data.DataChampFinal[4].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Entrepôt Fiscal" Binding="{Binding Path=Mobr_Identrepotfiscal}"
Visibility="{Binding Data.DataChampFinal[5].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Entrepôt Compte" Binding="{Binding Path=Mobr_Identrcpt}"
Visibility="{Binding Data.DataChampFinal[6].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Compte" Binding="{Binding Path=Comp_Id}"
Visibility="{Binding Data.DataChampFinal[7].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Couleur" Binding="{Binding Path=Comp_Idcouleur}"
Visibility="{Binding Data.DataChampFinal[8].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Sous Compte" Binding="{Binding Path=Mobr_Idsouscompte}"
Visibility="{Binding Data.DataChampFinal[9].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Type mouvement" Binding="{Binding Path=Mobr_Mouvement}"
Visibility="{Binding Data.DataChampFinal[10].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Type justificatif si ecrit auto." Width="Auto" Binding="{Binding Path=Mobr_Idtypeecrit}"
Visibility="{Binding Data.DataChampFinal[11].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Code Produit" Binding="{Binding Path=Prod_Id}"
Visibility="{Binding Data.DataChampFinal[12].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Degré" Binding="{Binding Path=Mobr_Degré}"
Visibility="{Binding Data.DataChampFinal[13].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Code Mouvement" Binding="{Binding Path=Como_Id}"
Visibility="{Binding Data.DataChampFinal[14].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Entrée/sortie" Binding="{Binding Path=Mobr_TypeMvt}"
Visibility="{Binding Data.DataChampFinal[15].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Sens" Binding="{Binding Path=Mobr_Sens}"
Visibility="{Binding Data.DataChampFinal[16].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Type de Tiers du Mvt." Binding="{Binding Path=Mobr_Idtierstyp}"
Visibility="{Binding Data.DataChampFinal[17].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Code du Tiers" Binding="{Binding Path=Mobr_Codetiers}"
Visibility="{Binding Data.DataChampFinal[18].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Désignation du Tiers" Binding="{Binding Path=Mobr_Nomtiers}"
Visibility="{Binding Data.DataChampFinal[19].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Type de Pièce Gestion" Binding="{Binding Path=Mobr_Idpiecegest}"
Visibility="{Binding Data.DataChampFinal[20].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Référence Pièce Origine1" Binding="{Binding Path=Mobr_Refpiece1}"
Visibility="{Binding Data.DataChampFinal[21].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
...
<DataGridTextColumn Header="CRA" Binding="{Binding Path=Mobr_Cra}"
Visibility="{Binding Data.DataChampFinal[26].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Type Nature Expédition" Binding="{Binding Path=Mobr_Idexptype}"
Visibility="{Binding Data.DataChampFinal[27].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Qte. régie en L." Binding="{Binding Path=Mobr_Qteregielitre}"
Visibility="{Binding Data.DataChampFinal[28].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Vol. effectif en L." Binding="{Binding Path=Mobr_Effectiflitre}"
Visibility="{Binding Data.DataChampFinal[29].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Qte. Gest. Commerciale en U." Binding="{Binding Path=Mobr_Qtegestcom}"
Visibility="{Binding Data.DataChampFinal[30].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Libre5" Binding="{Binding Path=Mobr_Libre5}"
Visibility="{Binding Data.DataChampFinal[40].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
<DataGridTextColumn Header="Libre6" Binding="{Binding Path=Mobr_Libre6}"
Visibility="{Binding Data.DataChampFinal[41].Cham_Order, Mode=TwoWay, Converter={StaticResource VisibleColumnConverter}, Source={StaticResource proxy}}" />
</DataGrid.Columns>
<DataGrid.ContextMenu>
<ContextMenu>
<MenuItem Header="Historique..." Command="{Binding GoSeeHistory}" />
</ContextMenu>
</DataGrid.ContextMenu>
</D:DataGridTemplate>
这一个很好：
<D:DataGridTemplate x:Name="Datagrid"
Behavior:ScrollViewerMonitor.AtEndCommand="{Binding LoadCommand}"
TablePaged:SortColumn.AtSortingColumnCommand="{Binding SortingColumnCommand}"
Grid.Column="0" Grid.Row="1" Grid.RowSpan="2" ItemsSource="{Binding DataProduits,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
<DataGrid.Resources>
<Helper:BindingProxy x:Key="proxy" Data="{Binding}" />
<CollectionViewSource x:Key="Currentcollection" Source="{Binding Path= ColumnName}" />
</DataGrid.Resources>
<DataGrid.Columns>
<DataGridTextColumn Header="ID" Binding="{Binding Path=Prod_Id}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Id" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Désignation" Binding="{Binding Path=Prod_Des}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Des" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Désignation court" Binding="{Binding Path=Prod_Lib}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Lib" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Millésime" Binding="{Binding Path=Prod_Millesime}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Millesime" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Type" Binding="{Binding Path=Prod_Type}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Type" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Centilisation" Binding="{Binding Path=Prod_centilisation}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_centilisation" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Appellation" Binding="{Binding Path=Prod_IdAppel}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_IdAppel" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Produit de base" Binding="{Binding Path=Prod_Idpdb}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idpdb" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Couleur" Binding="{Binding Path=Prod_Idcouleur}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idcouleur" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Ref. Douane" Binding="{Binding Path=Prod_Idrefdouane}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idrefdouane" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Catégorie" Binding="{Binding Path=Prod_Idcategorie}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idcategorie" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Regie" Binding="{Binding Path=Prod_Idprodregie}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idprodregie" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Statut regie" Binding="{Binding Path=Prod_Idsteap}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Idsteap" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
<DataGridTextColumn Header="Ste. d'appartenance" Binding="{Binding Path=Prod_Cloture}">
<DataGridTextColumn.Visibility>
<Binding Path="Data.ColumnName" ConverterParameter="Prod_Cloture" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" Source="{StaticResource proxy}" >
<Binding.Converter>
<Converters:VisibilityColumn CurrentCollection="{StaticResource Currentcollection}" />
</Binding.Converter>
</Binding>
</DataGridTextColumn.Visibility>
</DataGridTextColumn>
</DataGrid.Columns>
</D:DataGridTemplate>