[FAQ's: OD] How do I open an existing Excel Workbook?

If you need to programmatically open an existing workbook from within Excel itself you would use the Application.Workbooks.Open function. Now if you are automating Excel from another program language like VB 6 or a .NET language then you would create the application instance, select the Excel workbook and call the .Open function on the selected workbook.


Excel 97 - 2003 and VB.NET 2003 - 2008

VB.NET Code:

Option Explicit On
Option Strict On
'Copyright © 2009 by RobDog888 (VB/Office Guru™). All Rights reserved.
'
'              You may not reproduce or publish this 
'              code on any web site, online service, 
'              or distribute as source on any media 
'              without express permission.
 
'Add a reference to Microsoft Excel xx.0 Object Library
Imports Microsoft.Office.Interop
 
Public Class Form1
    'Declare our Excel Application object and Workbook object
    Private moApp As Excel.Application
    Private moWB As Excel.Workbook
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Open a selected workbook (*.xls)
        Dim OpenDlg As New OpenFileDialog
        Using OpenDlg
            With OpenDlg
                .CheckFileExists = True
                .CheckPathExists = True
                .Filter = "ExcelWorkbooks Only (*.xls)|*.xls"
                .FilterIndex = 1
                .Multiselect = False
                .ShowHelp = False
                .ShowReadOnly = False
                .Title = "Select an Excel Workbook file"
                'If a file is selected then lets open it
                If .ShowDialog = Windows.Forms.DialogResult.OK Then
                    'Call the .Open function and assign the return to the workbook variable for use 
                    'in other functions/areas in our app
                    moWB = moApp.Workbooks.Open(Filename:=.FileName)
                    'Show the opened workbook/application
                    moApp.Visible = True
                End If
            End With
        End Using
    End Sub
 
    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        'Close and dispose our objects
        If TypeName(moWB) <> "Nothing" Then
            'Can change to autosave or not
            moWB.Close() 'SaveChanges:=True
        End If
        moWB = Nothing
        If TypeName(moApp) <> "Nothing" Then
            moApp.Quit()
        End If
        moApp = Nothing
    End Sub
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        'Error handling on creating an Excel application as the user may not have it installed
        Try
            moApp = DirectCast(CreateObject("Excel.Application"), Excel.Application)
        Catch ex As Exception
            MessageBox.Show(ex.Message.ToString, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub
 
End Class