How can I avoid putting Draw in the ViewModel?

KirkKuykendall — Sat, 11 Dec 2021 06:28:31 GMT

Is it good MVVM practice keep Draw out of the ViewModel, (and only in the View)?

If so, how can I do that?

The VM needs the eventargs when DrawComplete fires, so I�??ve tried using MVVM Light�??s EventToCommand, but it throws an exception saying:

Cannot attach type "EventToCommand" to type "Draw". Instances of type "EventToCommand" can only be attached to objects of type "FrameworkElement".

<UserControl x:Class="GeoidApp2.TestPage"
    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:esri="http://schemas.esri.com/arcgis/client/2009"
  xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:ei="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.SL4" 
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">
   
    <UserControl.Resources>
        <esri:SimpleLineSymbol x:Key="DrawLineSymbol" Color="Green" Width="4" />
        <esri:SimpleFillSymbol x:Key="DrawFillSymbol" Fill="#3300FF00" BorderBrush="Green" BorderThickness="2" />

        <esri:Draw x:Key="MyDraw" LineSymbol="{StaticResource DrawLineSymbol}"  >           
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="DrawComplete">
                    <!--<ei:CallMethodAction TargetObject="{Binding}" MethodName="DrawDone"></ei:CallMethodAction>-->
                    <cmd:EventToCommand Command="{Binding DrawCompleteCommand,
                                          Mode=OneWay}" PassEventArgsToCommand="True" />
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </esri:Draw>
    </UserControl.Resources>
    <Grid x:Name="LayoutRoot" Background="White">
       
        <esri:Map x:Name="Map" Background="White" WrapAround="true" Loaded="Map_Loaded">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Loaded">
                    <i:InvokeCommandAction Command="{Binding MapLoadedCommand}"
                                          CommandParameter="{Binding ElementName=Map}" />
                </i:EventTrigger>
                <i:EventTrigger EventName="Loaded">
                    <i:InvokeCommandAction Command="{Binding WireDrawCommand}"
                                          CommandParameter="{StaticResource MyDraw}" />
                </i:EventTrigger>
            </i:Interaction.Triggers>
            <esri:ArcGISTiledMapServiceLayer ID="BaseLayer"
        Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" />
        </esri:Map>
    </Grid>
</UserControl>

topic How can I avoid putting Draw in the ViewModel? in ArcGIS API for Silverlight Questions

How can I avoid putting Draw in the ViewModel?