[英]WPF Binding don't update data
所以问题是,尽管我绑定了它,但无论我在文本框中更改文本,都不会更改代码中的属性。 我正在使用 MVVM 模式,所以:我的模型:
public class Shipment
{
public Shipment() {}
public int ShipmentId {get;set;}
//LP and Payer
[Required]
public long ExternalNumber {get ; set;}
public long MPKNumber { get; set; }
public long ContractNumber { get; set; }
public Payer Payer { get; set; }
public Payment Payment { get; set; }
//And much more but i'm working on these right now
}
我的视图模型:
public class PrepareNewViewModel : INotifyPropertyChanged
{
private Shipment shipment { get; set; }
public Shipment Shipment
{
get
{
return shipment;
}
set
{
if (shipment != value)
{
shipment = value;
RaisePropertyChanged("Shipment");
}
}
}
public PrepareNewViewModel()
{
Shipment = new Shipment();
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
而我的观点:
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:Controls ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
x:Class="SmartShipping.Views.Pages.PrepeareNew"
xmlns:local ="clr-namespace:SmartShipping.ViewModels"
xmlns:System="clr-namespace:System;assembly=mscorlib"
xmlns:Model ="clr-namespace:SmartShipping.Model"
mc:Ignorable="d"
d:DesignHeight="889" d:DesignWidth="959"
Title="PrepeareNew">
<Page.DataContext>
<local:PrepareNewViewModel/>
</Page.DataContext>
<Page.Resources>
<ObjectDataProvider x:Key="dataFromEnumPayer" MethodName="GetValues" ObjectType="{x:Type System:Enum}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="Model:Payer"/>
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
<ObjectDataProvider x:Key="dataFromEnumPayment" MethodName="GetValues" ObjectType="{x:Type System:Enum}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="Model:Payment"/>
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
</Page.Resources>
<GroupBox Header="LIST PRZEWOZOWY I PŁATNIK" HorizontalAlignment="Left"
VerticalAlignment="Top" Margin="10,131,0,0" Height="146" Width="458">
<Grid HorizontalAlignment="Left" Width="448" Margin="0,0,-2,0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="28*"/>
<ColumnDefinition Width="28*"/>
<ColumnDefinition Width="56*"/>
</Grid.ColumnDefinitions>
<Label Content="Nr zewnętrzny:" HorizontalAlignment="Left"
VerticalAlignment="Top" Margin="10,8,0,0" Width="138" Grid.ColumnSpan="2"/>
<TextBox Height="24" Margin="10,31,10,0" TextWrapping="Wrap"
Text="{Binding Shipment.ExternalNumber, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
VerticalAlignment="Top" Grid.ColumnSpan="2"/>
<Label Content="Nr MPK:" HorizontalAlignment="Left" VerticalAlignment="Top"
Margin="0,10,0,0" Grid.Column="2" Width="73"/>
<TextBox Height="24" Margin="0,31,10,0" TextWrapping="Wrap"
Text="{Binding Shipment.MPKNumber, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"
VerticalAlignment="Top" Grid.Column="2"
Background="{DynamicResource {x:Static SystemColors.ControlLightLightBrushKey}}"/>
<Label Content="Płatnik usługi:" HorizontalAlignment="Left"
VerticalAlignment="Top" Margin="10,69,0,0"/>
<ComboBox ItemsSource="{Binding Source={StaticResource dataFromEnumPayer}}"
Margin="10,92,0,0" VerticalAlignment="Top" Height="24"
Background="{DynamicResource {x:Static SystemColors.ControlLightLightBrushKey}}"/>
<Label Content="Forma płatności:" HorizontalAlignment="Left"
VerticalAlignment="Top" Margin="5,69,0,0" Grid.Column="1"/>
<ComboBox SelectedItem="{Binding Shipment.Payment}"
ItemsSource="{Binding Source={StaticResource dataFromEnumPayment}}"
Margin="10,92,10,0" VerticalAlignment="Top" Height="24"
Background="{DynamicResource {x:Static SystemColors.ControlLightLightBrushKey}}"
Grid.Column="1"/>
<Label Content="Nr umowy:" HorizontalAlignment="Left"
VerticalAlignment="Top" Margin="0,66,0,0" Grid.Column="2"/>
<TextBox HorizontalAlignment="Left" Height="24"
Margin="0,92,0,0" TextWrapping="Wrap"
VerticalAlignment="Top" Width="214" Grid.Column="2"
Text="{Binding Shipment.ContractNumber, ValidatesOnDataErrors=True}"/>
</Grid>
</GroupBox>
</Page>
难道我没有绑定模型的每个属性?
MVVM 的一个很好的经验法则是 ViewModel 和 View 具有一对一的关系。 如果您对 Shipment 的每个成员都有属性,那对我来说会更有意义。 否则,Shipment 的成员将不会更新。 尽管直观上 Shipment 在技术上发生了变化,但属性仅在您更新其值时才会更新 - 而不是它们的成员。
您的文本框在技术上仅以一种方式绑定。 当您更改它们时,Shipment 的成员不会更新。 我很好奇这是否可能,所以我在我正在从事的项目中自己测试了它,并且确实改变我的模型成员并没有触发 RaisePropertyChanged。
您需要在 View.cs 中设置数据上下文。 像这样(最好在构造函数中):
this.DataContext=shipmentObject;
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