Creating a non-trival custom GP tool - inputs, outputs, and responding to environment settings
' Copyright 2008 ESRI
' All rights reserved under the copyright laws of the United States
' and applicable international laws, treaties, and conventions.
' You may freely redistribute and use this sample code, with or
' without modification, provided you include the original copyright
' notice and use restrictions.
' See use restrictions at <your ArcGIS install location>/developerkit/userestrictions.txt.

Imports Microsoft.VisualBasic
Imports System
Imports ESRI.ArcGIS.Geoprocessing
Imports ESRI.ArcGIS.Geodatabase

Namespace GPPointFileInfo
  Public Class ESOutputCoordinateSystem
        Implements GPPointFileInfo.IESOutputCoordinateSystem
    Private Const _EnvironmentName As String = "outputCoordinateSystem"
    Private _spatialReference As ESRI.ArcGIS.Geometry.ISpatialReference

    Public Sub New(ByVal gpEnvironmentManager As IGPEnvironmentManager)
      Dim gpValue As IGPValue = gpEnvironmentManager.GetGPValue(_EnvironmentName)

      _spatialReference = GetSpatialReference(gpValue)
    End Sub

        Public ReadOnly Property SpatialReference() As ESRI.ArcGIS.Geometry.ISpatialReference Implements IESOutputCoordinateSystem.SpatialReference
                Return _spatialReference
            End Get
        End Property

    Private Function GetSpatialReference(ByVal gpValue As IGPValue) As ESRI.ArcGIS.Geometry.ISpatialReference
      Dim spatialReference As ESRI.ArcGIS.Geometry.ISpatialReference

      Dim gpCoordinateSystem As IGPCoordinateSystem = TryCast(gpValue, IGPCoordinateSystem)

      spatialReference = gpCoordinateSystem.SpatialReference

      Return spatialReference
    End Function
  End Class
End Namespace