UserControl上的DataGrid不显示绑定的ObservableCollection [英] DataGrid on UserControl doesn't display binded ObservableCollection
问题描述
我有一个MainWindow，其中包含一些用于加载集合的按钮:
I have a MainWindow with some buttons that loads a collection:
<Window x:Class="GUI.MainWindow.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:mainWindowViewModel="clr-namespace:GUI.MainWindow"
xmlns:s="clr-namespace:Helpers"
xmlns:configuration="clr-namespace:GUI.Configuration"
xmlns:results="clr-namespace:GUI.Results"
mc:Ignorable="d"
Title="{Binding Path=Model.Title}"
Width="Auto"
WindowStartupLocation="CenterScreen">
<Window.Resources>
<DataTemplate DataType="{x:Type results:ResultViewModel}">
<results:ResultView/>
</DataTemplate>
</Window.Resources>
<!--DataContext-->
<Window.DataContext>
<mainWindowViewModel:MainWindowViewModel />
</Window.DataContext>
<!--DataContext-->
<!--Main Grid-->
<Grid Name="MainGrid"
Margin="5"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="8*" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<!--Tabs-->
<TabControl Grid.Row="1"
Grid.RowSpan="2"
Grid.Column="0"
VerticalAlignment="Stretch">
<!--Result View-->
<TabItem Header="{Binding Model.TabImportHeader}">
<ContentControl Content="{Binding ResultViewModel}"/>
</TabItem>
</TabControl>
<!--Tabs-->
<!--Buttons-->
<Grid Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Button Grid.Row="0"
Grid.Column="0"
Margin="10"
Height="25"
Width="150"
Content="Load"
Command="{Binding LoadCommand}" />
<Button Grid.Row="0"
Grid.Column="2"
Margin="10"
Height="25"
Width="150"
Content="Reload"
Command="{Binding ReloadCommand}" />
</Grid>
<!--Buttons-->
</Grid>
<!--Main Grid-->
</Window>
然后我有一个UserControl，该控件应显示已加载的集合，但不显示任何内容.
Then I have a UserControl which should display the loaded collection, but shows nothing.
<UserControl x:Class="GUI.Results.ResultView"
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:local="clr-namespace:GUI.Results"
mc:Ignorable="d">
<UserControl.DataContext>
<local:ResultViewModel />
</UserControl.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="87*" />
<ColumnDefinition Width="415*" />
<ColumnDefinition Width="501*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<DataGrid Grid.Column="0"
Grid.ColumnSpan="3"
Grid.Row="0"
ItemsSource="{Binding Model.Collections}"
ColumnWidth="*"
AutoGenerateColumns="false"
HorizontalAlignment="Stretch"
IsReadOnly="True">
<DataGrid.Resources>
<Style TargetType="DataGridColumnHeader">
<Setter Property="HorizontalContentAlignment"
Value="Center" />
</Style>
</DataGrid.Resources>
<DataGrid.Columns>
<DataGridTextColumn Header="Filename"
Binding="{Binding ResultInfo.Filename}"
Width="Auto" />
<DataGridTextColumn Header="Score 1"
Binding="{Binding ResultInfo.Score1, StringFormat=F4, ConverterCulture=de-DE}"
Width="Auto" />
<DataGridTextColumn Header="Score 2"
Binding="{Binding ResultInfo.Score2, StringFormat=F4, ConverterCulture=de-DE}"
Width="Auto" />
<DataGridTextColumn Header="Score 3"
Binding="{Binding ResultInfo.Score3, StringFormat=F4, ConverterCulture=de-DE}"
Width="Auto" />
<DataGridTextColumn Header="Score 4"
Binding="{Binding ResultInfo.Score4, StringFormat=F4, ConverterCulture=de-DE}"
Width="Auto" />
<DataGridTextColumn Header="SaMP"
Binding="{Binding ResultInfo.SaMP}"
Width="Auto" />
<DataGridTextColumn Header="Spig"
Binding="{Binding ResultInfo.Spig}"
Width="Auto" />
<DataGridTextColumn Header="Ppig"
Binding="{Binding ResultInfo.Ppig, StringFormat=00.0##\\%}"
Width="Auto" />
<DataGridTextColumn Header="Pigment3"
Binding="{Binding ResultInfo.Pigment3}"
Width="Auto" />
<DataGridTextColumn Header="Pigment4"
Binding="{Binding ResultInfo.Pigment4}"
Width="Auto" />
<DataGridTextColumn Header="ZQ1"
Binding="{Binding ResultInfo.ZQ1}"
Width="Auto" />
<DataGridTextColumn Header="ZQ2"
Binding="{Binding ResultInfo.ZQ2}"
Width="Auto" />
<DataGridTextColumn Header="ZQ3"
Binding="{Binding ResultInfo.ZQ3}"
Width="Auto" />
<DataGridTextColumn Header="ZQ4"
Binding="{Binding ResultInfo.ZQ4}"
Width="Auto" />
<DataGridTextColumn Header="Message"
Binding="{Binding ResultInfo.Message}"
Width="Auto" />
<DataGridTextColumn Header="Distance"
Binding="{Binding ResultInfo.PowDistance, StringFormat=F2, ConverterCulture=de-DE}"
Width="Auto" />
</DataGrid.Columns>
</DataGrid>
</Grid>
</UserControl>
这是我将数据放入集合中的方式(如果我进行调试，则值在那里):
Here how I put the data inside the collection (values are there if I debug):
Application.Current.Dispatcher.Invoke(() => MainWindowViewModel.ResultViewModel.Model.Collections.Add(Collection));
Collections是ObservableCollection<>;
Collections is type of ObservableCollection<>;
似乎绑定中缺少某些内容，但是我对WPF和MVVM还是很陌生，但找不到. 我已经阅读了有关DependencyProperty的信息，但是我想为我的userControl使用ViewModel，因为它最终会变得更加复杂.
Seems that I'm missing something in the binding but I'm quite new to WPF and MVVM and I don't find it. I have read about DependencyProperty but I would like to have a ViewModel for my userControl as it will get eventually more complex.
我将非常感谢您的帮助.
I will really appreciate any help.
推荐答案
您有两个ResultViewModel实例，一个在MainWindowViewModel.ResultViewModel属性中，另一个直接分配给UserControl的DataContext:
You have two instances of ResultViewModel, one in the MainWindowViewModel.ResultViewModel property, the other directly assigned to the UserControl's DataContext:
<UserControl.DataContext>
<local:ResultViewModel />
</UserControl.DataContext>
从UserControl的XAML中删除上述内容.
Remove the above from the UserControl's XAML.
通常，UserControl永远不应具有其自己的"视图模型，并且永远不应在其XAML或后面的代码中显式设置其DataContext属性.这样做会覆盖继承的DataContext的值，该值包含正确的ResultViewModel实例.
In general, a UserControl should never have its "own" view model, and you should never explicitly set its DataContext property in its XAML or code behind. Doing so overrides the value of the inherited DataContext, which contains the correct ResultViewModel instance.
这篇关于UserControl上的DataGrid不显示绑定的ObservableCollection的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
