vb.net - 表格未定义 VB.NET

Question

我正在尝试将表单对象存储到变量中，但没有成功：

此代码不起作用：

Dim invoice_form As billing_new_invoice

    'Get last remote Row
    Dim last_row As Integer = CType(main.ActiveMdiChild, invoice_form).invoiceitems_new_invoice.Rows.Count - 1

    Dim count_row As Integer = CType(main.ActiveMdiChild, invoice_form).invoiceitems_new_invoice.Rows.Count()

此代码有效：

Dim invoice_form As billing_new_invoice

    'Get last remote Row
    Dim last_row As Integer = CType(main.ActiveMdiChild, billing_new_invoice).invoiceitems_new_invoice.Rows.Count - 1

    Dim count_row As Integer = CType(main.ActiveMdiChild, billing_new_invoice).invoiceitems_new_invoice.Rows.Count()

我需要将表单实例存储在变量（invoice_form）中，该变量可以在多行代码中使用，但它说（未定义类型'invoice_form'。）有人有想法解决这个问题吗？

Answer 1

不是很清楚是什么问题。我想你正在寻找这样的东西：

If TypeOf Me.ActiveMdiChild Is billing_new_invoice Then
  Dim invoice_Form As billing_new_invoice = Me.ActiveMdiChild

  Dim last_row As Integer = invoice_form.invoiceitems_new_invoice.Rows.Count - 1
  Dim count_row As Integer = invoice_form.invoiceitems_new_invoice.Rows.Count()

  //'etc

End If

代码不起作用的问题是它试图将其转换为变量，而不是类型。 invoice_form是变量，billing_new_invoice是类型。

Answer 2

CType 用于类型转换，而不是变量赋值。您要做的是首先将变量分配给表单，然后使用该变量：

Dim invoice_form As billing_new_invoice = CType(main.ActiveMdiChild, billing_new_invoice)
Dim last_row As Integer = invoice_form.invoiceitems_new_invoice.Rows.Count - 1