How to set custom fullextent?

Question

I have a WPF Map control whose extent I would like to restrict to a certain area (e.g. to the full extent of some layer). That is, a user should not be able to zoom out too far, or shift the map to an area outside that full extent.

How can I restrict Map display to a certain extent?

This is my code:

<esri:Map x:Name="Map" SizeChanged="Map_SizeChanged">
    <esri:ArcGISTiledMapServiceLayer x:ID="LB" ... />
    ...
</esri:Map>

And here is the code-behind (this code does not work):

void Map_SizeChanged(object sender, SizeChangedEventArgs e)
{
    if (currentExtent > Map.Zoom(Map.Layers["LB"].FullExtent)) // check the current extent of the map. If currentExtent is more than FullExtent
    {
        // jump back to full extent
        Map.Zoom(Map.Layers["LB"].FullExtent);
    }
}

I'd like to get something like that:

private void Map_SizeChanged(object sender, SizeChangedEventArgs e)
{
    … // get current extent of the map

    … // check the current extent of the map.
      // if currentExtent is more than FullExtent jump back to full extent
}

I'm using the ESRI API for WPF and C# in Visual Studio 2010.

Answer 1

There is a ConstrainExtentBehavior that you can add to the Map.

See here.

<esri:Map x:Name="MyMap" Extent="-120,30,-60,60">
. . . 
  <i:Interaction.Behaviors>
    <esriBehaviors:ConstrainExtentBehavior
      ConstrainedExtent="-120,30,-60,60"/> 
  </i:Interaction.Behaviors>
</esri:Map>

You can get the extent of your layer and set it as the ContrainedExtent.