[英]WPF-MVVM, Master - Detail datagrid with calculated column. Rate * Quantity = Total
我有綁定到viewmodel的數據輸入表單。 我遵循EF代碼優先方法,並且細節表由模型中的可觀察集合表示,如下所示。
public partial class item
{
public item()
{
orders = new ObservableCollection<order>();
}
}
一切正常,但在少數情況下,我有一個主條目,其中有網格形式的詳細信息。 這是xaml部分,它將SelectedItem.Orders綁定到詳細信息網格。
<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>
在這種情況下,我想在用戶在網格中鍵入價格和數量后立即計算總數。 我知道,如果我們在viewmodel中具有相關屬性,就可以處理它。 但就我而言,訂單是項目模型中的集合。
提前致謝。
好的,在論壇上尋求支持后,我找到了適合我情況的解決方案。 只需將其張貼在這里,對某人有用。
簡要介紹對我有用的最終答案。 可以做的是用視圖模型包裝每個實體。 因此,在那里使用該集合的數據網格將其itermssource綁定到OrderVM的可觀察集合,而不是Order(實體類型)。
然后,您可以將實體的屬性與我的視圖模型中的屬性包裝在一起,並在其中放置任何其他業務邏輯,例如計算,並在其中一個因素發生變化時在計算字段上更改屬性。
根據此建議,我對代碼的以下更改幫助我解決了該問題; 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)現在具有以下三個重要屬性,即Orders = OrderVM的ObservableCollection OrderVM SelectedItem //選擇進行編輯的項目SelectedOrder //選擇進行編輯的訂單
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屬性public item SelectedItem {get {return _selectedItem; }設置{_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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