How to assosiate two ViewModels with Single View in WPF, C#

Question

Hi All,

I am new to MVVM , I have one basic doubt ,

How can I use two View Models in a Single View .

If any sample sudo code would be appreciated .

Regards
Rams

Answer 1

Create two new UserControls named View1 and View2 as below:
Code for View1.xaml

<Grid>  
        <DataGrid AutoGenerateColumns="False" DataContext="{Binding Model1s}" ItemsSource="{Binding }"  >  
            <DataGrid.Columns>  
                <DataGridTextColumn Header="ID" Binding="{Binding ID}" />  
                <DataGridTextColumn Header="Name" Binding="{Binding Name}" />  
            </DataGrid.Columns>  
        </DataGrid>  
    </Grid>  

Code for View2.xaml

  <Grid>  
        <DataGrid DataContext="{Binding Model2s}" AutoGenerateColumns="False" ItemsSource="{Binding }">  
            <DataGrid.Columns>  
                <DataGridTextColumn Header="Name" Binding="{Binding Name}" />  
                <DataGridTextColumn Header="Sex" Binding="{Binding Sex}" />  
            </DataGrid.Columns>  
        </DataGrid>  
    </Grid>  

Code for MainWindow.xaml

 <Window.Resources>  
        <DataTemplate DataType="{x:Type local:ViewModel1}">  
            <local:View1/>  
        </DataTemplate>  
        <DataTemplate DataType="{x:Type local:ViewModel2}">  
            <local:View2/>  
        </DataTemplate>  
    </Window.Resources>  
  
    <Window.DataContext>  
        <local:MainWindowViewModel />  
    </Window.DataContext>  
    <StackPanel>  
        <ContentControl Name="Con1" Content="{Binding CurrentView1}" />  
        <ContentControl Name="Con2" Content="{Binding CurrentView2}" />  
    </StackPanel>  

Code for MainWindowViewModel.cs

public class MainWindowViewModel  
    {  
        private object _currentView1;  
        private object _currentView2;  
        private object _view1;  
        private object _view2;  
        public MainWindowViewModel()  
        {  
            _view1 = new View1();  
            _view2 = new View2();  
            Model1s = new ViewModel1().Model1s;  
            Model2s = new ViewModel2().Model2s;  
            CurrentView1 = _view1;  
            CurrentView2 = _view2;  
        }  
  
        public object CurrentView1  
        {  
            get { return _currentView1; }  
            set  
            {  
                _currentView1 = value;  
            }  
        }  
  
        public object CurrentView2  
        {  
            get { return _currentView2; }  
            set  
            {  
                _currentView2 = value;  
            }  
        }  
  
        public ObservableCollection<Model1> Model1s { get; set; } = new ObservableCollection<Model1>();  
          
        public ObservableCollection<Model2> Model2s { get; set; } = new ObservableCollection<Model2>();  
  
    }  

Is it what you want? If it is not, please ponit out and give me more details to analyze.

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Answer 2

I will show you a demo of binding two viewmodels in one view.

Code for Model1:

public class Model1  
    {  
        public string Name { get; set; }  
        public int ID { get; set; }  
    }  
  
  
    public class Model2  
    {  
        public string Name { get; set; }  
        public string Sex { get; set; }  
    }  

Code for ViewModels:

 public class ViewModel1  
    {  
        public ViewModel1()  
        {  
            Model1s = new ObservableCollection<Model1>()  
            {  
            new Model1() { Name = "Jim", ID = 1 },  
            new Model1() { Name = "Red", ID = 2 },  
            new Model1() { Name = "Green", ID = 3 } ,  
            new Model1() { Name = "Black", ID = 4 }  
            };  
  
             
        }  
        public ObservableCollection<Model1> Model1s { get; set; }  
    }  
  
  
    public class ViewModel2  
    {  
        public ViewModel2()  
        {  
            Model2s = new ObservableCollection<Model2>()  
            {  
            new Model2() { Name = "Jack", Sex = "Boy" },  
            new Model2() { Name = "Dais", Sex = "Girl" },  
            new Model2() { Name = "Peter", Sex = "girl" } ,  
            new Model2() { Name = "Black", Sex = "Boy" }  
            };  
  
  
        }  
        public ObservableCollection<Model2> Model2s { get; set; }  
    }  

Code for View:

 <Window.Resources>  
        <local:ViewModel1 x:Key="MyViewModel1"></local:ViewModel1>  
        <local:ViewModel2 x:Key="MyViewModel2"></local:ViewModel2>  
    </Window.Resources>  
    <StackPanel>  
        <Grid>  
            <DataGrid DataContext="{StaticResource MyViewModel1}" AutoGenerateColumns="False" ItemsSource="{Binding Model1s}" >  
                <DataGrid.Columns>  
                    <DataGridTextColumn Header="ID" Binding="{Binding ID}" />  
                    <DataGridTextColumn Header="Name" Binding="{Binding Name}" />  
                </DataGrid.Columns>  
            </DataGrid>  
        </Grid>  
  
        <Grid>  
            <DataGrid DataContext="{StaticResource MyViewModel2}" AutoGenerateColumns="False" ItemsSource="{Binding Model2s}" >  
                <DataGrid.Columns>  
                    <DataGridTextColumn Header="Name" Binding="{Binding Name}" />  
                    <DataGridTextColumn Header="Sex" Binding="{Binding Sex}" />  
                </DataGrid.Columns>  
            </DataGrid>  
        </Grid>  
    </StackPanel>  

The result picture is:

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Answer 3

A viewmodel is a class/object. A viewmodel can contain an instance of class/object within it.

public class TestVM1
{

 public string FirstName {get; set;}

 public TestVM2 Testvm2 {get; set;) = new TestVM2();

}

public class TestVM2
{

public string Address {get; set:}

}

==============

some code somewhere in the project.

TestVM1 testvm1 = new TestVM1();

testvm1.FirstName = 'Larry";

testvm1.Testvm2.Address = "77 Hollywood Blvd";