How to listen to document events

In this topic

• Getting a reference to the document object
• Wiring the document event in the event interface
• Registering the handler method to the event
• Complete code
• Code fragments

Getting a reference to the document object

1. To listen to document events of an ArcGIS Desktop application, get a reference to the document object from the application. (Code)
   
   The following table shows example entry points to get a reference to the application object:
   

Wiring the document event in the event interface

Registering the handler method to the event

1. Define a method to handle the event. This handler method is called when the event is fired. The handler method signature must match the event you are listening to. For the NewDocument event, the handler method signature is simple. (Code)

2. Add code in the event handler method to complete this task.

Complete code

using ESRI.ArcGIS.Framework;
using ESRI.ArcGIS.ArcMapUI;

namespace ArcGISProject
{
    public class howToClass
    {
        //Event member variable.
        private IDocumentEvents_Event m_docEvents=null;

        //Wiring.
        private void SetUpDocumentEvent(IDocument myDocument)
        {
            m_docEvents=myDocument as IDocumentEvents_Event;
            m_docEvents.NewDocument += new IDocumentEvents_NewDocumentEventHandler
                (howToClass_NewDocument);
        }

        //Event handler method.
        void howToClass_NewDocument()
        {
            System.Windows.MessageBox.Show("New document at: " +
                DateTime.Now.ToLongTimeString());
        }

    }
}

Imports ESRI.ArcGIS.Framework
Imports ESRI.ArcGIS.ArcMapUI

Public Class howToClass
    
    'Event member variable.
    Private m_docEvents As IDocumentEvents_Event
    
    'Wiring.

    Sub SetUpDocumentEvent(myDocument As IDocument)
        m_docEvents=CType(myDocument, IDocumentEvents_Event)
        AddHandler m_docEvents.NewDocument, AddressOf OnNewDocument
    End Sub
    
    'Event handler method.

    Sub OnNewDocument()
        MsgBox("New document at: " + DateTime.Now.ToLongTimeString())
    End Sub
    
End Class

Code fragments

• Code 1 : Getting the document object from the application - The following code requires referencing the ESRI.ArcGIS.Framework assembly in the project:

IApplication app=hook as IApplication;
IDocument appDocument=app.Document;

Dim app As IApplication=CType(hook, IApplication)
Dim appDocument As IDocument=app.Document

public class howToClass
{
    private IDocumentEvents_Event m_docEvents=null;

    private void SetUpDocumentEvent(IDocument myDocument)
    {
        m_docEvents=myDocument as IDocumentEvents_Event;
        ...
    }
}

Public Class howToClass
    Private m_docEvents As IDocumentEvents_Event
    
    Sub SetUpDocumentEvent(myDocument As IDocument)
        m_docEvents=CType(myDocument, IDocumentEvents_Event)
        ...
    End Sub

End Class

• Code 3 : Wiring NewDocument event - The following code requires referencing ESRI.ArcGIS.Framework and ESRI.ArcGIS.ArcMapUI in the project:

private IDocumentEvents_Event m_docEvents=null;

private void SetUpDocumentEvent(IDocument myDocument)
{
    m_docEvents=myDocument as IDocumentEvents_Event;
    m_docEvents.NewDocument += ...
}

Private m_docEvents As IDocumentEvents_Event

Sub SetUpDocumentEvent(myDocument As IDocument)
    m_docEvents=CType(myDocument, IDocumentEvents_Event)
    AddHandler m_docEvents.NewDocument, ...
End Sub

void OnNewDocument()

Sub OnNewDocument()

m_docEvents.NewDocument += new IDocumentEvents_NewDocumentEventHandler
    (howToClass_NewDocument);
... 

void howToClass_NewDocument(){}

AddHandler m_docEvents.NewDocument, AddressOf OnNewDocument
...

Sub OnNewDocument()
    
End Sub

See Also:

• ESRI.ArcGIS.Framework
• ESRI.ArcGIS.ArcMapUI