This example passes data between View Models through the ISupportParameter interface (using the DevExpress MVVM Framework).
Files to Look At
- ChildView1.xaml (VB: ChildView1.xaml)
- ChildView2.xaml (VB: ChildView2.xaml)
- MainView.xaml (VB: MainView.xaml)
- ChildPOCOViewModel.cs (VB: ChildPOCOViewModel.vb)
- ChildViewModelBase.cs (VB: ChildViewModelBase.vb)
- MainViewModel.cs (VB: MainViewModel.vb)
Documentation
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Example Code
View/ChildView1.xaml
XAML<UserControl x:Class="Example.View.ChildView1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModel="clr-namespace:Example.ViewModel"
xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<UserControl.DataContext>
<ViewModel:ChildViewModelBase/>
</UserControl.DataContext>
<Grid>
<TextBlock Text="This View has a ViewModel derived from the ViewModelBase class" TextWrapping="Wrap"/>
</Grid>
</UserControl>
View/ChildView2.xaml
XAML<UserControl x:Class="Example.View.ChildView2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModel="clr-namespace:Example.ViewModel"
xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300"
DataContext="{dxmvvm:ViewModelSource ViewModel:ChildPOCOViewModel}">
<Grid>
<TextBlock Text="This View has a POCO ViewModel" TextWrapping="Wrap"/>
</Grid>
</UserControl>
View/MainView.xaml
XAML<UserControl x:Class="Example.View.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModel="clr-namespace:Example.ViewModel"
xmlns:View="clr-namespace:Example.View"
xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignHeight="500" d:DesignWidth="600"
DataContext="{dxmvvm:ViewModelSource ViewModel:MainViewModel}">
<dxmvvm:Interaction.Behaviors>
<dx:DXMessageBoxService/>
</dxmvvm:Interaction.Behaviors>
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<Button Content="Change Parameter1" Command="{Binding ChangeParameter1Command}"/>
<Button Content="Change Parameter2" Command="{Binding ChangeParameter2Command}"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<Border BorderThickness="1" BorderBrush="Black" Margin="10" Width="300" Height="100">
<View:ChildView1 dxmvvm:ViewModelExtensions.ParentViewModel="{Binding DataContext, ElementName=LayoutRoot}"
dxmvvm:ViewModelExtensions.Parameter="{Binding DataContext.Parameter1, ElementName=LayoutRoot}"/>
</Border>
</StackPanel>
<StackPanel Orientation="Horizontal">
<Border BorderThickness="1" BorderBrush="Black" Margin="10" Width="300" Height="100">
<View:ChildView2 dxmvvm:ViewModelExtensions.ParentViewModel="{Binding DataContext, ElementName=LayoutRoot}"
dxmvvm:ViewModelExtensions.Parameter="{Binding DataContext.Parameter2, ElementName=LayoutRoot}"/>
</Border>
</StackPanel>
</StackPanel>
</Grid>
</UserControl>
ViewModel/ChildPOCOViewModel.cs(vb)
C#using DevExpress.Mvvm;
using DevExpress.Mvvm.DataAnnotations;
namespace Example.ViewModel {
public class ChildPOCOViewModel : ISupportParameter {
[ServiceProperty(SearchMode=ServiceSearchMode.PreferParents)]
protected virtual IMessageBoxService MessageBoxService { get { return null; } }
public virtual object Parameter { get; set; }
protected virtual void OnParameterChanged() {
if(Parameter is string)
MessageBoxService.Show("ChildPOCOViewModel: Parameter = " + (string)Parameter);
}
}
}
ViewModel/ChildViewModelBase.cs(vb)
C#using DevExpress.Mvvm;
namespace Example.ViewModel {
public class ChildViewModelBase : ViewModelBase {
IMessageBoxService MessageBoxService { get { return GetService<IMessageBoxService>(ServiceSearchMode.PreferParents); } }
protected override void OnParameterChanged(object parameter) {
base.OnParameterChanged(parameter);
if(parameter is string)
MessageBoxService.Show("ChildViewModelBase: Parameter = " + (string)parameter);
}
}
}
ViewModel/MainViewModel.cs(vb)
C#namespace Example.ViewModel {
public class MainViewModel {
public virtual string Parameter1 { get; set; }
public virtual string Parameter2 { get; set; }
public void ChangeParameter1() {
counter1++;
Parameter1 = "Parameter #" + counter1.ToString();
}
public void ChangeParameter2() {
counter2++;
Parameter2 = "Parameter #" + counter2.ToString();
}
int counter1 = 0;
int counter2 = 0;
}
}