如何强制更新视图
本文关键字：新视图 更新 何强制 | 更新日期: 2023-09-27 17:50:30
我有一个包含两个Views和一个ViewModel的应用程序。第一个View[AddView]用于创建对象，second[ShowView]用于显示对象。ViewModel[DummyData]由ObservableCollection和创建新对象所需的一切组成。
我的问题是:当我从AddView添加对象时，如何强制更新ShowView
这是DummyData
#region Fake Database
private static ObservableCollection<Student> fakeStudentDataLayer;
public UserDummyData()
{
fakeStudentDataLayer = new ObservableCollection<Student>()
{
new Student(){Name = "test1", Surname = "surnameTest1", Age = 22, Barcode = "testbarcode1", ClassLetter = 'A', ClassNumber = 6, ID = 1, ParentName = "parentTest1", ParentSurname = "ParentSurnameTitle1", Number = 22, DateOfCreation = new DateTime(2008, 12, 2), LastCheckIn = new DateTime(2014, 3, 9)},
new Student(){Name = "test2", Surname = "surnameTest2", Age = 22, Barcode = "testbarcode2", ClassLetter = 'B', ClassNumber = 8, ID = 2, ParentName = "parentTest2", ParentSurname = "ParentSurnameTitle2", Number = 22, DateOfCreation = new DateTime(2008, 12, 2), LastCheckIn = new DateTime(2014, 3, 9)},
new Student(){Name = "test3", Surname = "surnameTest3", Age = 22, Barcode = "testbarcode3", ClassLetter = 'C', ClassNumber = 10, ID = 3, ParentName = "parentTest3", ParentSurname = "ParentSurnameTitle3", Number = 22, DateOfCreation = new DateTime(2008, 12, 2), LastCheckIn = new DateTime(2014, 3, 9) }
};
}
public ObservableCollection<Student> FakeStudentDataLayer
{
get { return fakeStudentDataLayer; }
set { fakeStudentDataLayer = value; RaisePropertyChanged("FakeStudentDataLayer"); }
}
#endregion
#region Commands
private RelayCommand _addStudentCommand;
public ICommand NewStudentCommand
{
get
{
return _addStudentCommand
?? (_addStudentCommand = new RelayCommand(() =>
{
//Create new student
Student student = new Student();
//Set new student's properties
//TODO: Add ID value
student.Name = Name;
student.Surname = Surname;
student.ParentName = ParentName;
student.ParentSurname = ParentSurname;
student.ClassLetter = Convert.ToChar(ClassLetter.ToUpper());
student.ClassNumber = NumberConvertor(ClassNumber);
student.Class = Appender(ClassLetter, ClassNumber);
student.Number = Int32.Parse(Number);
student.Age = AgeConvertor(Age);
student.Barcode = Barcode;
student.ID = 6;
student.LastCheckIn = DateTime.Now;
student.DateOfCreation = DateTime.Now;
//TODO: ADD student to DATABASE
FakeStudentDataLayer.Add(student);
}));
}
}
#endregion
这是AddView
<Grid>
<!--DataContext-->
<Grid.DataContext>
<dc:UserDummyData/>
</Grid.DataContext>
<!--Student TextBoxes-->
<TextBlock x:Name="StudentNameWaterMark"
Grid.Column="2"
Text="{x:Static p:Resources.Name}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=StudentNameContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="StudentNameContentTextBox"
Grid.Column="2"
Text="{Binding Name}"
Width="{Binding ElementName=StudentNameWaterMark,
Path=Width}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent">
</TextBox>
<TextBlock Name="StudentSurnameWaterMark"
Grid.Column="2" Grid.Row="1"
Text="{x:Static p:Resources.Surname}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=StudentSurnameContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="StudentSurnameContentTextBox"
Grid.Column="2" Grid.Row="1"
Text="{Binding Surname}"
Width="{Binding ElementName=StudentSurnameWaterMark,
Path=Width}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent">
</TextBox>
<!--Parent TextBoxes-->
<TextBlock x:Name="ParentNameWaterMark"
Grid.Column="2" Grid.Row="2"
Text="{x:Static p:Resources.ParentName}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=ParentNameContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="ParentNameContentTextBox"
Grid.Column="2" Grid.Row="2"
Text="{Binding ParentName}"
Width="{Binding ElementName=ParentNameWaterMark,
Path=Width}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent">
</TextBox>
<TextBlock x:Name="ParentSurnameWaterMark"
Grid.Column="2" Grid.Row="3"
Text="{x:Static p:Resources.ParentSurname}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=ParentSurnameContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="ParentSurnameContentTextBox"
Grid.Column="2" Grid.Row="3"
Text="{Binding ParentSurname}"
Width="{Binding ElementName=ParentSurnameWaterMark,
Path=Width}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent">
</TextBox>
<!--Student Details TextBoxes-->
<TextBlock x:Name="AgeWaterMark"
Grid.Column="5"
Text="{x:Static p:Resources.Age}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=AgeContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="AgeContentTextBox"
Grid.Column="5"
Text="{Binding Age}"
Width="{Binding ElementName=AgeWaterMark,
Path=Width}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent"/>
<Grid Grid.Column="5" Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<TextBlock x:Name="GradeNumberWaterMark"
Text="{x:Static p:Resources.GradeNumber}"
Style="{StaticResource GradeWaterMarkStyle}"
Visibility="{Binding
ElementName=GradeNumberContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="GradeNumberContentTextBox"
Width="{Binding ElementName=GradeNumberWaterMark,
Path=Width}"
Text="{Binding ClassNumber}"
Style="{StaticResource TextBoxTextStyle}"
Background="Transparent"/>
</Grid>
<Grid Grid.Column="5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<TextBlock x:Name="GradeLetterWaterMark"
Text="{x:Static p:Resources.GradeLetter}"
Style="{StaticResource GradeWaterMarkStyle}"
Visibility="{Binding
ElementName=GradeLetterContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="GradeLetterContentTextBox"
Width="{Binding ElementName=GradeLetterWaterMark,
Path=Width}"
Text="{Binding ClassLetter}"
Style="{StaticResource TextBoxTextStyle}"
Background="Transparent"/>
</Grid>
</Grid>
<TextBlock x:Name="NumberWaterMark"
Grid.Column="5" Grid.Row="2"
Text="{x:Static p:Resources.NumberInClass}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=NumberContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="NumberContentTextBox"
Grid.Column="5" Grid.Row="2"
Width="{Binding ElementName=NumberWaterMark,
Path=Width}"
Text="{Binding Number}"
Style="{StaticResource BasicTextBoxTextStyle}"
Background="Transparent"/>
<TextBlock x:Name="BarcodeWaterMark"
Grid.Column="5" Grid.Row="3"
Text="{x:Static p:Resources.Barcode}"
Style="{StaticResource WaterMarkStyle}"
Visibility="{Binding
ElementName=BarcodeContentTextBox,
Path=Text.IsEmpty, Converter={StaticResource
WaterMarkRemover}}"/>
<TextBox x:Name="BarcodeContentTextBox"
Grid.Column="5" Grid.Row="3"
Width="{Binding ElementName=BarcodeWaterMark,
Path=Width}"
Text="{Binding Barcode}"
Style="{StaticResource BarcodeTextBoxTextStyle}"
Background="Transparent"/>
<!--Buttons-->
<Grid Grid.Row="4" Grid.ColumnSpan="6">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Button Grid.Row="1"
Content="{x:Static p:Resources.Add}"
HorizontalAlignment="Left"
Style="{StaticResource ButtonStyle}"
Command="{Binding NewStudentCommand}"/>
<Button Grid.Column="2"
Content="{x:Static p:Resources.Clear}"
HorizontalAlignment="Right"
Style="{StaticResource ButtonStyle}"/>
</Grid>
</Grid>
这是ShowView
<Grid>
<!--DataContext-->
<Grid.DataContext>
<dc:UserDummyData/>
</Grid.DataContext>
<!--DataGrid-->
<DataGrid AutoGenerateColumns="False"
CanUserAddRows="True"
CanUserDeleteRows="True"
ItemsSource="{Binding FakeStudentDataLayer}">
<DataGrid.Columns>
<DataGridTextColumn Header="{x:Static p:Resources.sName}"
Binding="{Binding Name}"/>
<DataGridTextColumn Header="{x:Static p:Resources.sSurname}"
Binding="{Binding Surname}"/>
<DataGridTextColumn Header="{x:Static p:Resources.sAge}"
Binding="{Binding Age}"/>
<DataGridTextColumn Header="{x:Static p:Resources.sGrade}"
Binding="{Binding Class}"/>
<DataGridTextColumn Header="{x:Static p:Resources.sNumber}"
Binding="{Binding Number}"/>
<DataGridTextColumn Header="{x:Static p:Resources.LastCheckIn}"
Binding="{Binding LastCheckIn}"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
注意:如果我把一个代码从ShowView在AddView然后一切工作，但如果他们是这样-一个两个单独的视图，DataGrid不更新。
编辑:我试着用同样的结构做一个更简单的项目。令人难以置信的是，它成功了，我没有做任何不同的事情。新的采样器项目和这个项目的不同之处在于我使用了更基本的模型——只有两个属性。我没有本地化，如果那很重要的话。所以我的问题是，为什么它在一个较小的项目中有效，而不是在这个项目中。
强制更新到底是什么意思?如果您的意思是添加数据，请尝试使用scaffolding
http://www.asp.net/visual-studio/overview/2013/aspnet-scaffolding-overview我不确定你的代码到底看起来如何，但我认为你有一个窗口，包含多个视图，你的窗口有一个MainViewModel例如，里面的视图有自己的视图模型。如果MainViewModel创建并处理其他视图，那么它就获得了它们的实例，并能够在那里调用方法。
所以也许你的问题是你想知道如何在视图模型之间进行通信?
这里有一个我正在思考的小例子。如果你有一个MainViewModel，一个DataAddViewModel和一个ShowViewModel。MainViewModel创建DataAddViewModel和ShowViewModel。DataAddViewModel有一个事件，当插入新数据时触发该事件。ShowViewModel有一个绑定到Listview之类的，以及一个触发该绑定的公共方法。
注意:下面只是一个例子。
DataAddViewModel中的可能事件
public event EventHandler DataAddedEvent;
private void RaiseDataAddedEvent()
{
var handler = this.DataAddedEvent;
if (handler == null) return;
handler(this, EventArgs.Empty);
}
MainViewModel中可能的事件注册和处理
var _ShowVm = new ShowViewModel();
var _AddVm = new DataAddViewModel();
_addVm.DataAddedEvent += OnDataAdded;
//Notify our ShowViewModel about the new data
private void OnDataAdded(object sender, EventArgs e)
{
_ShowVm.DataAdded();
}
ShowViewModel
public void DataAdded(){
RaisePropertyChanged("NameOfMyBinding");
}
我最好的猜测是问题来自于您使用了两个单独的UserDummyData实例。在Show视图和Add视图中，您可以这样设置DataContext:
<Grid.DataContext>
<dc:UserDummyData/>
</Grid.DataContext>
这两行都构造了一个新的UserDummyData对象。因此，当您向其中一个添加数据时，不会在另一个中添加数据。你应该这样做:
<Grid ... DataContext="{x:Static p:Resources.MyUserDummyDataInstance}"/>
然后，当您向一个UserDummyData添加学生时，两个视图都将显示新学生，因为它们的两个列表(实际上是同一个列表)都有新学生。