Imports Excel = Microsoft.Office.Interop.Excel
Imports System.Diagnostics
Imports System.IO.Path
Imports System.Runtime.InteropServices

Public Class xlRunning

    Shared xlApp As Excel.Application
    Shared xlBook As Excel.Workbook
    Shared xlSheet As Excel.Worksheet
    Const xlFile As String = "C:\XVBT\Case.xls"


    Shared Function Basic_Approach() As Boolean

        Try
            'Check to see if an Excel session exists or not.
            'If not running it will through a COM exception.
            xlApp = CType(Marshal.GetActiveObject("Excel.Application"), Excel.Application)
        Catch ex As Exception
            'Instantiate a new Excel session.
            xlApp = New Excel.Application
        End Try

        Try
            xlBook = xlApp.Workbooks.Open(xlFile)
            With xlApp
                .Visible = True
                .UserControl = True
            End With

        Catch ex As Exception

        Finally
            xlBook = Nothing
            xlApp = Nothing

        End Try

    End Function

    Shared Function Process_Approach() As Boolean

        Try
            'Check to see if (at least) one Excel session is running.
            If Process.GetProcessesByName("Excel").Length > 0 Then
                xlApp = CType(GetObject(, "Excel.Application"), Excel.Application)
            Else
                ''Instantiate a new Excel session.
                xlApp = New Excel.Application
            End If

            xlBook = xlApp.Workbooks.Open(xlFile)

            With xlApp
                .UserControl = True
                .Visible = True
            End With

        Catch ex As Exception

        Finally
            xlBook = Nothing
            xlApp = Nothing

        End Try

    End Function

    Shared Function Process_Approach_BindToMoniker() As Boolean

        Try
            '1.If no Excel session is running then a new one is instantiated
            'with the wanted workbook opened.
            '2. If an Excel session exists and the wanted workbook is not open 
            'then it will be opened.
            '3. If the workbook is already open then it will be moved to the 
            'front.

            xlBook = CType(Marshal.BindToMoniker(xlFile), Excel.Workbook)
            xlApp = CType(xlBook.Parent, Excel.Application)

            With xlApp
                .ScreenUpdating = False
                .Visible = True
                With .Windows(GetFileName(xlFile))
                    .Visible = True
                    .Activate()
                End With
                '.UserControl = True
            End With

        Catch ex As Exception

        Finally
            xlApp.ScreenUpdating = True
            xlBook = Nothing
            xlApp = Nothing
        End Try

    End Function

    Shared Function Start_Excel_Process_Do_Stuff_End_Excel_Process() As Boolean

        Dim procIDSumBefore As Integer = 0
        Dim procIDSumAfter As Integer = 0

        'Sum all present Excel processes' IDs.
        For Each xlProcess As Process In Process.GetProcessesByName("Excel")
            procIDSumBefore = procIDSumBefore + xlProcess.Id
        Next

        Try
            'Instantiate our Excel process.
            xlApp = New Excel.Application
            xlBook = xlApp.Workbooks.Open(xlFile)

            With xlApp
                .Visible = True
                .UserControl = True
            End With

            'Sum all processes' IDs including our Excel process's ID.
            For Each xlProcess As Process In Process.GetProcessesByName("Excel")
                procIDSumAfter = procIDSumAfter + xlProcess.Id
            Next

            'Find our Excel process' ID.
            Dim procID As Integer = procIDSumAfter - procIDSumBefore

            'Do the stuff with the Excel file.

            'Grab our Excel process.
            Dim myXLProcess As Process = Process.GetProcessById(procID)

            With myXLProcess
                'Allow users to save the work.
                .CloseMainWindow()
                'Make sure that our Excel process actuals is closed.
                'In order to check it a timer is used.
                .WaitForExit(60000)
            End With

            'If not our Excel process has ended we need to close it now. 
            If Not myXLProcess.HasExited Then
                myXLProcess.Kill()
            End If

        Catch ex As Exception

        Finally
            xlBook = Nothing
            xlApp = Nothing
        End Try

    End Function

    Shared Function Get_All_Excel_Sessions() As Boolean

        Try
            If Process.GetProcessesByName("Excel").GetLength(0) > 0 Then
                xlApp = CType(GetObject(, "Excel.Application"), Excel.Application)
                xlBook = xlApp.Workbooks.Add
                xlSheet = CType(xlBook.Worksheets(1), Excel.Worksheet)

                Dim xlProcesses() As Process = Process.GetProcessesByName("Excel")

                For Each xlProcess As Process In xlProcesses
                    Dim Counter As Integer = Counter + 1
                    xlSheet.Cells(1, Counter) = xlProcess.MainWindowTitle.ToString
                Next
            End If

        Catch ex As Exception

        Finally
            xlSheet = Nothing
            xlBook = Nothing
            xlApp = Nothing
        End Try

    End Function

End Class