If you have an object that needs to provide Print and Print Preview capabilities the object needs to implement the IPrintExt interface. The ExPrint component communicates with an object being printed using the IPrintExt interface. The methods like Preview and DoPrint fail if the PrintExt property is not set. You can use the PrintExts property to send multiple objects/components to the same document.  Use the PrintExt property to send a single object to the printer.

The ExPrint component provides Print and Print Preview features for components like: eXGantt, eXG2antt, eXMLGrid, eXGrid, eXTree, eXList, eXCalendar, eXComboBox, eXPropertiesList, eXEdit, eXFileView, eXOrgChart, eXSchedule, eXPivot and so on.

The following samples show in different programming languages how to provide the print-preview capabilities for eXG2antt control:

• Access. The Object method of the G2antt1 object gets the native or the original component. 

Private Sub callPreview()
    With Print1
        Set .PrintExt = G2antt1.Object
        .preview
    End With
End Sub

• VB6. The Object method of the G2antt1 object gets the native or the original component. 

Private Sub callPreview()
    With Print1
        Set .PrintExt = G2antt1.Object
        .Preview
    End With
End Sub

• VFP. The Object method of the G2antt1 object gets the native or the original component. 

with thisform.Print1
	.PrintExt = thisform.G2antt1.Object
	.Preview
endwith

• VB.NET ( ActiveX version ). The GetOcx method of the G2antt1 object gets the native or the original component. 

Private Sub callPreview()
    With AxPrint1
        .PrintExt = AxG2antt1.GetOcx()
        .Preview()
    End With
End Sub

• VB.NET ( /NET or /WPF Assembly ). 

Private Sub callPreview()
    With Exprint1
        .PrintExt = Exg2antt1
        .Preview()
    End With
End Sub

• C# ( ActiveX version ). The GetOcx method of the G2antt1 object gets the native or the original component. 

private void callPreview()
{
    axPrint1.PrintExt = axG2antt1.GetOcx();
    axPrint1.Preview();

}

• C# ( /NET or /WPF Assembly ). 

private void callPreview()
{
    exprint1.PrintExt = exg2antt1;
    exprint1.Preview();
}

• C++ (6.0). The m_print member of the CWindowMFCDlg class, is of CExPrint type ( which has been defined by the class wizard ). The m_g2antt member is of CG2antt type that has been defined by the class wizard. The GetControlUnknown method retrieves a pointer to IUnknown interface being implemented by the original component, which is the pointer required by the PrintExt method before calling the Preview or DoPrint method of the eXPrint component.

void CWindowMFCDlg::callPreview()
{
	m_print.SetPrintExt( m_g2antt.GetControlUnknown() );
	m_print.Preview();
}

• C++ (2005,2008). The m_print member of the CWindowMFCDlg class, is of CExPrint type ( which has been defined by the class wizard ). The m_g2antt member is of CG2antt type that has been defined by the class wizard. The GetControlUnknown method retrieves a pointer to IUnknown interface being implemented by the original component, which is the pointer required by the PrintExt method before calling the Preview or DoPrint method of the eXPrint component.

void CWindowMFCDlg::callPreview()
{
	m_print.put_PrintExt( m_g2antt.GetControlUnknown() );
	m_print.Preview();
}

• C++ Builder (2009). The DefaultDispatch function of the TOleControl retrieves the original object, so it can be passed to PrintExt function of the eXPrint in order to print or print preview the component, as seen in the callpreview function:

void TForm1::callPreview()
{
	Print1->PrintExt = G2antt1->DefaultDispatch;
	Print1->Preview();
}

• Delphi (2009). The DefaultDispatch function of the TOleControl retrieves the original object, so it can be passed to PrintExt function of the eXPrint in order to print or print preview the component, as seen in the callpreview function:

procedure callPreview(P : TPrint; G : TG2antt);
begin
with P do
begin
 PrintExt := G.DefaultDispatch;
 Preview();
end;
end;

callPreview( Print1, G2antt1 );

• Clarion. Code under ?PrintThis button, with some properties:
  
   ?Print{'Settings(10)'} = 1
   ?Print{'PrintExt'} = ?Gantt{PROP:Object}
   ?Print{'AsScreen'} = False                                   
   ?Print{'PageOrientation'} = 2
   ?Print{'Caption'} = 'Some text'
   ?Print{'Settings(6)'} = 1500
   ?Print{'Settings(7)'} = 1500
   ?Print{'Settings(8)'} = 1500
   ?Print{'Settings(9)'} = 1500
   ?Print{'Font.Name'}   = 'Arial'
   ?Print{'Font.Size'}   = 9
   ?Print{'Preview'}