[英]WPF-MVVM, Master - Detail datagrid with calculated column. Rate * Quantity = Total
我有绑定到viewmodel的数据输入表单。 我遵循EF代码优先方法,并且细节表由模型中的可观察集合表示,如下所示。
public partial class item
{
public item()
{
orders = new ObservableCollection<order>();
}
}
一切正常,但在少数情况下,我有一个主条目,其中有网格形式的详细信息。 这是xaml部分,它将SelectedItem.Orders绑定到详细信息网格。
<UserControl x:Class="ABCD.Views.itemView"
....
DataContext="{Binding itemMaster, Source={StaticResource Locator}}"
Height="Auto" Width="Auto">
<Grid>
<Grid.ColumnDefinitions.... />
<Grid.RowDefinitions..../>
<DataGrid AutoGenerateColumns="False" VerticalAlignment="Top" ItemsSource="{Binding items}" SelectedItem="{Binding SelectedItem}" Name="dgitems" HorizontalAlignment="Stretch" RowDetailsVisibilityMode="VisibleWhenSelected" >
<DataGrid.Columns>
<DataGridTextColumn x:Name="ItemNameColumn" Binding="{Binding Path=ItemName}" Header="Item Name" Width="125" />
<DataGridTextColumn x:Name="ItemCodeColumn" Binding="{Binding Path=ItemCode}" Header="Item Code" Width="75" />
<DataGridTextColumn x:Name="StockColumn" Binding="{Binding Path=StockLevel}" Header="Stock" Width="60" />
</DataGrid.Columns>
</DataGrid>
<Label Grid.Column="3" Grid.Row="0" Margin="3,3,3,3" Content="Item Code" VerticalAlignment="Center" />
<TextBox Grid.Column="4" Grid.Row="0" HorizontalAlignment="Left" Margin="3,3,3,3" Name="ctrlItemCode" Text="{Binding Path=SelectedItem.ItemCode, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true}" Width="120" Height="Auto" VerticalContentAlignment="Center" />
<Label Grid.Column="3" Grid.Row="2" Margin="3,3,3,3" Content="Product Name" VerticalAlignment="Center" />
<TextBox Grid.Column="4" Grid.Row="2" HorizontalAlignment="Left" Margin="3,3,3,3" Name="ctrlProductName" Text="{Binding Path=SelectedItem.ItemName, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true}" Width="120" Height="Auto" VerticalContentAlignment="Center" />
<DataGrid Grid.Column="2" Grid.Row="16" Grid.ColumnSpan="3" Height="145" AutoGenerateColumns="False" VerticalAlignment="Top" ItemsSource="{Binding SelectedItem.Orders}" Name="dgOrders" HorizontalAlignment="Stretch" >
<DataGrid.Columns>
<DataGridTemplateColumn Width="120">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox DisplayMemberPath="OrderNumber" SelectedValuePath="OrderId" ItemsSource="{Binding Path=DataContext.Orders, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" SelectedValue="{Binding Path=OrderId}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn x:Name="QtyColumn" Binding="{Binding Path=Quantity}" Header="Qty" Width="75" />
<DataGridTextColumn x:Name="PriceColumn" Binding="{Binding Path=Price}" Header="Price" Width="75" />
<DataGridTextColumn x:Name="TotalColumn" Binding="{Binding Path=Total}" Header="Total" Width="75" />
</DataGrid.Columns>
</DataGrid>
</Grid>
</UserControl>
在这种情况下,我想在用户在网格中键入价格和数量后立即计算总数。 我知道,如果我们在viewmodel中具有相关属性,就可以处理它。 但就我而言,订单是项目模型中的集合。
提前致谢。
好的,在论坛上寻求支持后,我找到了适合我情况的解决方案。 只需将其张贴在这里,对某人有用。
简要介绍对我有用的最终答案。 可以做的是用视图模型包装每个实体。 因此,在那里使用该集合的数据网格将其itermssource绑定到OrderVM的可观察集合,而不是Order(实体类型)。
然后,您可以将实体的属性与我的视图模型中的属性包装在一起,并在其中放置任何其他业务逻辑,例如计算,并在其中一个因素发生变化时在计算字段上更改属性。
根据此建议,我对代码的以下更改帮助我解决了该问题; 如下所示的OrderVM集合;
public class OrderVM : baseViewModel
{
public OrderVM()
{ }
private order _order;
public order Order
{
get
{
return _order;
}
set
{
_order = value;
NotifyPropertyChanged();
}
}
public decimal Percentage
{
get
{
return (decimal)_order.Percentage; //Without passing the selectedOrder.Percentage like this, It doesn't work
}
set
{
_order.Percentage = value;
NotifyPropertyChanged();
calculate();
}
}
public decimal Qty
{
get
{
return (decimal)_order.Qty;
}
set
{
_order.Qty = value;
NotifyPropertyChanged();
calculate();
}
}
public decimal Total
{
get
{
return (decimal)_order.Total;
}
set
{
_order.Total = value;
NotifyPropertyChanged();
}
}
private void calculate()
{
_order.Total = _order.Price * _order.Qty;
NotifyPropertyChanged("Total");
}
}
itemVM(MainVM)现在具有以下三个重要属性,即Orders = OrderVM的ObservableCollection OrderVM SelectedItem //选择进行编辑的项目SelectedOrder //选择进行编辑的订单
public class itemsVM : baseViewModel
{
private item _selectedItem;
private ObservableCollection<OrderVM> _orders;
public ObservableCollection<OrderVM> Orders
{
get
{
if (SelectedItem != null)
{
_orders = new ObservableCollection<OrderVM>();
foreach (Order ord in SelectedItem.Orders)
{
_orders.Add(new OrderVM { Order = ord });
}
return _orders;
}
else
return null;
}
set { _orders = value; }
}
// SelectedItem属性public item SelectedItem {get {return _selectedItem; }设置{_selectedItem =值; NotifyPropertyChanged(); NotifyPropertyChanged(“ CanModify”); NotifyPropertyChanged(“ Orders”); }}
private OrderVM _selectedorder;
public OrderVM SelectedOrder
{
get
{
return _selectedorder;
}
set
{
_selectedorder = value;
NotifyPropertyChanged();
}
}
}
而我的xaml如下:
<DataGrid Grid.Column="2" Grid.Row="16" Grid.ColumnSpan="3" Height="145" AutoGenerateColumns="False" VerticalAlignment="Top"
ItemsSource="{Binding Orders}" SelectedItem="{Binding SelectedOrder}" Name="dgOrders" HorizontalAlignment="Stretch" >
<DataGrid.Columns>
<DataGridTextColumn x:Name="QtyColumn" Binding="{Binding Path=Qty}" Header="Qty" Width="75" />
<DataGridTextColumn x:Name="PriceColumn" Binding="{Binding Path=Price}" Header="Price" Width="75" />
<DataGridTextColumn x:Name="TotalColumn" Binding="{Binding Path=Total}" Header="Price" Width="75" />
</DataGrid.Columns>
</DataGrid>
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