Hi Michael. 

Here is a quick walkthrough on how to do this for the column chooser, excel exporting would be basically the same. 

1. Implement ICommandTarget on your UserControl:

public partial class MainPage : UserControl, ICommandTarget

2.  in the SupportsCommand method, return true for any command that you want to support:

 bool ICommandTarget.SupportsCommand(ICommand command)

        {

            return command is OpenColumnChooserCommand;

        }

3. in the GetParameter method, return what object you want to perform an action on, in this case the xamGrid:

object ICommandTarget.GetParameter(Infragistics.Controls.CommandSource source)

        {

            return grid;

        }

4. Create a CommandSource class, this will be used to hook the event up to your button:

 public class MyGridCommands : CommandSource

    {

        protected override ICommand ResolveCommand()

        {

            return new OpenColumnChooserCommand();

        }

    }

5. Implement the command

public class OpenColumnChooserCommand : CommandBase

    {

        public override bool CanExecute(object parameter)

        {

            if (parameter is XamGrid)

                return true;

            return false;

        }

        public override void Execute(object parameter)

        {

            XamGrid grid = parameter as XamGrid;

            if (grid != null)

                grid.ShowColumnChooser();

        }

    }

6. Finally, hook up your command to your button:

<Button Content="Column Chooser">

                    <ig:Commanding.Command>

                        <local:MyGridCommands EventName="Click" >

                        </local:MyGridCommands>

                    </ig:Commanding.Command>

                </Button>

Hope this helps simplify things.

-SteveZ