Using maptool with dockpane causes SystemNullReferenceException when calling dockpane from maptool

[JeffSauder]

I am working on a tool that uses a dockpane to display results from features in a box from a maptool.  I actually have already created this tool with a windows form and it works really well except for one issue that I don't think can be resolved, so I'm looking at the dockpane, which I believe is the only other way to get a form in Pro.  However, I open the dockpane, then draw the box with the maptool, and when I call a function in the dockpane a null reference exception is returned.  The data that I'm passing to the dockpane is not null, and I even tested it without passing any data and the dockpane still comes back null.

I am using Esri sample "MapToolIdentifyWithDockpane" as a reference, and I have everything set up the same way as in that sample.  The sample works, mine does not.

I have this in the config.daml for the dockpane:

<dockPanes>
<dockPane id="CustomIDDockPane_dpIDTools" caption="dpIDTools" className="dpIDToolsViewModel" dock="float" dockWith="esri_core_projectDockPane">
<content className="dpIDToolsView" />
</dockPane>
</dockPanes>

This is what I have in Module1 to define the dockpane:

internal class Module1 : Module
{
private static Module1 _this = null;
private static dpIDToolsViewModel _dpIDToolsVM = null;

public static Module1 Current
{
get
{
return _this ?? (_this = (Module1)FrameworkApplication.FindModule("CustomIDDockPane_Module"));
}
}
internal static dpIDToolsViewModel dpIDToolsVM { get; set; }
}

I call this from the tool, this is where the error occurs:

Module1.dpIDToolsVM.LoadIDResults(mapLayerNames, feat);

This is the code in the viewmodel that the above line is calling:

internal void LoadIDResults(List<string> layerNames, Dictionary<BasicFeatureLayer, List<long>> featureLayerList)
{
List<IDFeaturesInLayer> iList = new List<IDFeaturesInLayer>();
foreach (KeyValuePair<BasicFeatureLayer, List<long>> b in featureLayerList)
{
IDFeaturesInLayer i = new IDFeaturesInLayer();
i.Value = b.Key;
i.Text = b.Key.ToString();
iList.Add(i);
}
}

Thank you in advance for any assistance offered.

Jeff

[KirkKuykendall1 · Accepted solution]

I created a new AddIn project ProAppModule1, then added two items: a Dockpane and a MapTool.

I added code to the OnSketchCompleteAsync in MapTool1.cs using the id from the daml file (ProAppModule1_Dockpane1):

protected override Task<bool> OnSketchCompleteAsync(Geometry geometry)
{
    // added this code:
    var dockPaneID = "ProAppModule1_Dockpane1";
    var paneVm = FrameworkApplication.DockPaneManager.Find(dockPaneID)
        as Dockpane1ViewModel;
    if (paneVm != null)
    {
        paneVm.Heading = Environment.TickCount.ToString();
    }
    return base.OnSketchCompleteAsync(geometry);
}

I ran it, clicked the Maptool1 button, then clicked on the map twice:

Note that I made no changes to the Module1.cs or Dockpane1ViewModel.cs.

The only change was to MapTool1.cs.  

[JeffSauder]

Thanks Kirk, that worked.  The sample that I was looking at didn't have it defined that way, it was using the definition in Module1.  This was much simpler.  I appreciate you looking at this, this will get me going on to the next challenge in this app.

Thanks,

Jeff

[KirkKuykendall1]

What they are suggesting would scale a better as your code evolves.  When things get complicated its often better to have the each component talk to the module instead of talking directly to each other.

[JeffreySauder]

I'm going to move forward with this one, as it's a fairly simple app, but definitely will continue trying to get the other method to work.  This new api is definitely a learning curve but I'm getting a lot more used to it.