使用OpenFilleDailog打开文件。

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim fdlg As OpenFileDialog = New OpenFileDialog()
        fdlg.Title = "VB.net打开文件对话框的使用"
        fdlg.InitialDirectory = "c:"
        fdlg.Filter = "All files (*.*)|*.*"
        fdlg.FilterIndex = 2
        fdlg.RestoreDirectory = True
        If fdlg.ShowDialog() = DialogResult.OK Then
       TextBox1.Text = fdlg.FileName
        End If
    End Sub
附上示例的所有代码：（UseOpenFileDailog.VB)
Public Class UseOpenFileDialog
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        'This call is required by the Windows Form Designer.
        InitializeComponent()
        'Add any initialization after the InitializeComponent() call
    End Sub