Trying to used class derived from SelectionMapAction causes exception

BrianTrout — Thu, 28 Jul 2011 23:28:57 GMT

When I tried to derive a class from SelectionMapAction and use it, ESRI code raises an exception. I checked that the constructor was being called and it was. I have tried what I can think of and I am stumped. To make sure it wasn't something specific to my map, I duplicated this issue using the "Mobile Walkthrough (10.0)" (BasicWorkThrough_Win) sample code and a different map.

My code changes to the sample code are below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ESRI.ArcGIS.Mobile.MapActions;

namespace WindowsFormsApplication2
{
    public class CustomSelectionMapAction : SelectionMapAction
    {
        public CustomSelectionMapAction()
            : base()
        {
        }

        public CustomSelectionMapAction(System.ComponentModel.IContainer container)
            : base(container)
        {

        }
    }
}

Then I replaced the Pan button code with:

private void Pan_Click(object sender, EventArgs e)
    {
      //map1.CurrentMapAction = panMapAction1;
        map1.CurrentMapAction = new ESRI.ArcGIS.Mobile.MapActions.SelectionMapAction();  //line 1
        map1.CurrentMapAction = new CustomSelectionMapAction();  //line 2
    }

When I click the button, line 1 using the SelectionMapAction goes through fine, but line 2 using my Custom class generates this exception in esri code:

System.NullReferenceException was unhandled
  Message=Object reference not set to an instance of an object.
  Source=System.Windows.Forms
  StackTrace:
       at System.Windows.Forms.Cursor..ctor(Stream stream)
       at ESRI.ArcGIS.Mobile.MapActions.SelectionMapAction.OnActiveChanging(Boolean active)
       at ESRI.ArcGIS.Mobile.MapActions.MapAction.set_Active(Boolean value)
       at ESRI.ArcGIS.Mobile.Map.set_CurrentMapActionIndex(Int32 value)
       at ESRI.ArcGIS.Mobile.Map.set_CurrentMapAction(MapAction value)
       at WindowsFormsApplication2.Form1.Pan_Click(Object sender, EventArgs e) in C:\Documents and Settings\brian.trout\Desktop\BasicWorkThrough_Win\WindowsFormsApplication2\Form1.cs:line 87
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at WindowsFormsApplication2.Program.Main() in C:\Documents and Settings\brian.trout\Desktop\BasicWorkThrough_Win\WindowsFormsApplication2\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

Am I doing something wrong?

Re: Trying to use class derived from SelectionMapAction causes exception

BrianTrout — Sun, 12 Dec 2021 02:21:21 GMT

I just tried switching:

public class CustomSelectionMapAction : ESRI.ArcGIS.Mobile.MapActions.SelectionMapAction

public class CustomSelectionMapAction : ESRI.ArcGIS.Mobile.MapActions.DragRectangleMapAction

And it works without an error. I am missing something related specifically to the SelectionMapAction class.

topic Trying to used class derived from SelectionMapAction causes exception in ArcGIS for Windows Mobile Questions

Trying to used class derived from SelectionMapAction causes exception

Re: Trying to use class derived from SelectionMapAction causes exception