Select All items in ListView with MVVM

I am trying to select all Items in a ListView, using mvvm. Using code-behind, I have tried SelectAll() and foreach to select them, but I would like to use MVVM like the rest of my project. Any ideas?

Here is the listview:

<ListView x:Name="TransformerList"  ItemsSource="{Binding CurrentStations}" Margin="16,250,0,10.4" SelectionMode="Multiple" HorizontalAlignment="Left" Width="411">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Select">
                <i:InvokeCommandAction Command="{Binding SeeAllCustomersCommand}"  CommandParameter="{Binding Item1}"/>
            </i:EventTrigger>
            <i:EventTrigger EventName="SelectionChanged">
                <i:InvokeCommandAction Command="{Binding SelectedCustomersChangedCommand}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>
        <ListView.ItemContainerStyle>
            <Style TargetType="{x:Type ListViewItem}">
                <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}" />
                <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=TransformerIsSelected}" />
            </Style>
        </ListView.ItemContainerStyle>
        <ListView.View>
            <GridView>
                <GridViewColumn Header="Nettstasjon" Width="70" DisplayMemberBinding="{Binding Path=Name}" />
                <GridViewColumn Header="Område" Width="210" DisplayMemberBinding="{Binding Path=Area}"/>
                <GridViewColumn Header="Radial" Width="110" DisplayMemberBinding="{Binding Path=Radial}"/>
            </GridView>
        </ListView.View>
    </ListView>

and the button:

public ICommand cmd_VelgAlle { get { return new RelayCommand(on_cmd_VelgAlle);  } }
    private void on_cmd_VelgAlle()
    {
        foreach (item i in CurrentStations) //the item here gives an error "type or namespace could not be found"
        {
            i.TransformerIsSelected = true;
        }
    }

And the mvvm:

private bool _TransformerIsSelected;
    public bool TransformerIsSelected
    {
        get { return _TransformerIsSelected; }
        set
        {
            _TransformerIsSelected = value;
            RaisePropertyChanged("TransformerIsSelected");
        }
    }

You need to create a ListViewItem Style:

<ListView.ItemContainerStyle>
    <Style TargetType="ListViewItem">
        <Setter Property="IsSelected" Value="{Binding IsSelected}" />
    </Style>
</ListView.ItemContainerStyle>

Create a property in Model class:

public bool IsSelected
{
    get { return isSelected; }
    set 
    { 
        isSelected = value;
        RaiseChange("IsSelected");
    }
}

And iterate your ItemSource to set IsSelected true for all items.(In ViewModel)

foreach(item i in yourCollection)
{
    i.IsSelected = true;
}

Update:

Use Style as:

<ListView.ItemContainerStyle>
        <Style TargetType="{x:Type ListViewItem}">                
            <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=TransformerIsSelected}" />
        </Style>
</ListView.ItemContainerStyle>

Command:

 private void on_cmd_VelgAlle()
    {
        //Item is the class your CurrentStations is made of(i guess something like `station` in your design)
        //i.e if CurrentStations is list of string then Item will be string
        foreach (Item i in CurrentStations) 
        {
            i.TransformerIsSelected = true;
        }
    }