变量未声明.权限级别错误

Question

Option Strict On
Public Class Form1
'Project:  
'Author: 
'Date created: 9/8/2011
'Program Description: Program.
Private Sub btnData_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnData.Click
    '0. Declare variables
    Dim customerName As String
    Dim phoneNum As String
    Dim ticketPrice As Double
    Dim firstName, lastName As String
    Dim position As Integer
    Dim amountPaid As Double
    Dim areCode As String
    '1. Collect data: Customer name, phone number, ticket amount, and cash paid (use an input box)
    'get customer name from a textbox
    customerName = CStr(txtCustName.Text)
    'get phone number from a masked textbox
    phoneNum = mskPhone.Text
    'get ticket price from a textbox
    ticketPrice = CDbl(Val(txtTicket.Text))
    'get cash paid from a input box
    amountPaid = CDbl(Val(InputBox("Cash paid", "Lab2", "20")))
    '2. Rearrange name (Last, First)
    position = customerName.IndexOf(" ")
    firstName = customerName.Substring(0, position)
    lastName = customerName.Substring(position + 1)
    '3. Extract area code
    areCode = phoneNum.Substring(1, 3)
    '4. Calculate the change
    '5. Print data. Use the working version as a reference for your output.
    'print customer name
    lstDisplay.Items.Add("Customer Name: " & lastName & ", " & firstName)
End Sub
End Class

Answer 1

这个错误是不言自明的。txtCustName在Form1中使用，但没有定义。在使用变量之前，需要先定义它，语法如下:

Dim txtCustName As Textbox

是否txtCustName(我假设是一个Textbox)存在于你的形式?