Visual Basic InputBox closing error

Question

This is a bit of a weird question, and apologies for the vast amount of code the question contains, but, I've been given somebody else's project to maintain, and the user has come to me with an error. There is a button which opens the InputBox, seen below.

The form is used to enter a path of a file to import. If the user enters no path, or an incorrect one, an error is displayed - fine. Now, the problem is, is that if the user presses the 'Cancel' button or the x in the top right to close the form, it also returns the same error, saying that the path cannot be found.

After looking through the following code, I can't work out how to make it so that the error is not displayed when pressing the x or Cancel, so can anybody help me out at all?

 Private Sub btnImport_Click(sender As Object, e As EventArgs) Handles btnImport.Click

    Try
        Dim importbox As String = InputBox("Input path", "Import", "")
        Dim fi As New FileInfo(importbox)
        Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Text;Data Source=" & fi.DirectoryName

        Dim conn As New OleDbConnection(connectionString)
        conn.Open()

        Dim add1 As String = ""
        Dim add2 As String = ""
        Dim add3 As String = ""
        Dim add4 As String = ""
        Dim add5 As String = ""
        Dim postcode As String = ""
        Dim telephone As String = ""
        Dim fax As String = ""
        Dim email As String = ""
        Dim customercode As String = ""
        Dim customername As String = ""
        Dim webpage As String = ""
        Dim mobile As String = ""

        Dim headerTable As DataTable = ugHeaders.DataSource
        Dim csvArray(headerTable.Rows.Count) As String
        Dim i As Integer = 0
        For Each dr As DataRow In headerTable.Rows
            csvArray(i) = dr.Item("CSVName")
        Next

        For Each dr As DataRow In headerTable.Rows
            Select Case dr.Item("DBName").ToString.Trim
                Case "Add1"
                    add1 = dr.Item("CSVName")
                Case "Add2"
                    add2 = dr.Item("CSVName")
                Case "Add3"
                    add3 = dr.Item("CSVName")
                Case "Add4"
                    add4 = dr.Item("CSVName")
                Case "Add5"
                    add5 = dr.Item("CSVName")
                Case "PostCode"
                    postcode = dr.Item("CSVName")
                Case "Telephone"
                    telephone = dr.Item("CSVName")
                Case "Fax"
                    fax = dr.Item("CSVName")
                Case "Email"
                    email = dr.Item("CSVName")
                Case "Customer_Name"
                    customername = dr.Item("CSVName")
                Case "Customer_Code"
                    customercode = dr.Item("CSVName")
                Case "webpage"
                    webpage = dr.Item("CSVName")
                Case "mobile_phone"
                    mobile = dr.Item("CSVName")
            End Select
        Next

        Dim sqlSelect As String = "SELECT Company, [" & add1 & "], [" & add3 & "], [" & postcode & "], [" & add2 & "], " & _
                                          "[" & telephone & "], [" & fax & "], [" & email & "], [" & customercode & "], " & _
                                          "[" & add4 & "], [" & add5 & "], [" & webpage & "], [" & mobile & "] FROM " & fi.Name

        Dim cmdSelect As New OleDbCommand(sqlSelect, conn)

        Dim adapter1 As New OleDbDataAdapter(cmdSelect)

        Dim ds As New DataSet
        adapter1.Fill(ds, "DATA")

        pb_progress.Maximum = ds.Tables(0).Rows.Count
        pb_progress.Value = 0

        For Each dr As DataRow In ds.Tables(0).Rows
            Try
                Debug.WriteLine(dr.Item(customercode).ToString.Trim)

                If dr.Item(customercode).ToString.Trim = "" Then
                    Dim str As String = dr.Item(customername)
                    If str.Trim = "" Then Continue For
                    Dim length As Integer = str.Length
                    If length < 20 Then
                    Else
                        length = 20
                    End If

                    str = Replace(str.Substring(0, length), " ", "_").ToUpper
                    str = Regex.Replace(str, "[^a-zA-Z _&]", "")

                    Dim found As Boolean = True
                    Dim loopcount As Integer = 1

                    Do Until found = False
                        Dim checkSql As String = "SELECT * FROM Customers WHERE [Customer_Code] = @ccode"
                        Dim checkCmd As New OleDb.OleDbCommand(checkSql, con)
                        checkCmd.Parameters.AddWithValue("@ccode", str)
                        Dim checkDa As New OleDb.OleDbDataAdapter(checkCmd)
                        Dim checkDt As New DataTable
                        checkDa.Fill(checkDt)

                        If checkDt.Rows.Count <> 0 Then
                            found = True
                            str &= CStr(loopcount)
                            loopcount += 1
                        Else
                            found = False
                        End If
                    Loop

                    dr.Item(customercode) = str
                Else
                    Dim found As Boolean = True
                    Dim loopcount As Integer = 1
                    Do Until found = False
                        Dim checkSql As String = "SELECT * FROM Customers WHERE [Customer_Code] = @ccode"
                        Dim checkCmd As New OleDb.OleDbCommand(checkSql, con)
                        checkCmd.Parameters.AddWithValue("@ccode", dr.Item(customercode))
                        Dim checkDa As New OleDb.OleDbDataAdapter(checkCmd)
                        Dim checkDt As New DataTable
                        checkDa.Fill(checkDt)

                        If checkDt.Rows.Count <> 0 Then
                            found = True
                            dr.Item(customercode) &= CStr(loopcount)
                            loopcount += 1
                        Else
                            found = False
                        End If
                    Loop
                End If

                Dim sql As String
                sql = "INSERT INTO Customers(Customer_Code, Customer_Name, Contract_Payment_Terms, Aq_Date, Telephone, Fax, Email, Average_Payment_Terms, webpage, mobile_phone) " & _
                    "VALUES(@ccode, @cname, 30, #01/01/2016#, @ctele, @cfax, @email, 30, @webpage, @mobile);"
                Dim cmd As New OleDb.OleDbCommand(sql, con)
                With cmd.Parameters
                    .AddWithValue("@ccode", dr.Item(customercode))
                    .AddWithValue("@cname", dr.Item(customername))
                    .AddWithValue("@ctele", dr.Item(telephone).ToString.Truncate(48))
                    .AddWithValue("@cfax", dr.Item(fax))
                    .AddWithValue("@email", dr.Item(email))
                    .AddWithValue("@webpage", dr.Item(webpage))
                    .AddWithValue("@mobile", dr.Item(mobile))
                End With
                cmd.ExecuteNonQuery()

                sql = "INSERT INTO [Customer_Addresses] (Cust_Code, PostCode, Alias, Add1, Add2, Add3, Add4, Add5) VALUES(@ccode, @pcode, 'Default'" & _
                    ",@add1, @add2, @add3, @add4, @add5);"
                cmd = New OleDb.OleDbCommand(sql, con)
                With cmd.Parameters
                    .AddWithValue("@ccode", dr.Item(customercode))
                    .AddWithValue("@pcdoe", dr.Item(postcode))
                    .AddWithValue("@add1", dr.Item(add1))
                    .AddWithValue("@add2", dr.Item(add2))
                    .AddWithValue("@add3", dr.Item(add3))
                    .AddWithValue("@add4", dr.Item(add4))
                    .AddWithValue("@add5", dr.Item(add5))
                End With
                cmd.ExecuteNonQuery()

            Catch ex As Exception
                Debug.WriteLine(ex.Message)
            End Try


            pb_progress.Increment(1)
        Next

        MsgBox("Import successful", MsgBoxStyle.OkOnly, "Success")

    Catch ex As Exception
        errorLog(ex)
    End Try
End Sub

Answer 1

Inputbox will always return a String.

• If the Users presses "OK" it will return the String put into the TextBox.
• If he cancels the box by pressing X or Cancel it returns "".

I would generally not recommend using an Inputbox for getting a filepath. Use an OpenFileDialog instead. If you have the fullpath already in your Clipboard you can just paste it into the Filename-Textboxof the OFD and press enter.

This should get you started:

Dim ofd as new OpenFileDialog()
// Show the File Dialog to the user and detect he pressed OK or Cancelled
if ofd.ShowDialog = Windows.Forms.DialogResult.OK
      // Always check, if the file really exists
      if IO.File.exists(ofd.FileName)
         importbox = ofd.FileName
      Else
         msgbox("File does not exist")
         Exit Sub
      End if
Else
   Exit Sub
End if