Question

Public Class Form1
Public Structure Stock
    Dim prodSKU As String
    Dim sizeAmt As Integer
    Dim prodName As String
    Dim category As String
    Dim sellPrice As Decimal
    Dim buyPrice As Decimal
End Structure

Dim product(300) As Stock

Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
    product(0).prodSKU = txtSKU.Text
    product(1).prodSKU = "af"
    Call CheckData(Stock, txtSKU, product, txtName)

End Sub


Function CheckData(Stock As Object, txtSku As TextBox, product() As Object, txtName As TextBox)
        For index = 0 To 299
            txtSku.Text = product(index).prodSKU
            txtName.Text = product(index).prodName
            If txtSku.Text = product(index).prodSKU Or txtName.Text = product(index).prodName Then
                Dim Msg, Style, Title, Response
                Msg = "That SKU/Product Name already exists, enter another"    ' Define message.
                Style = vbOK    ' Define buttons.
                Title = "Repeated Saved Data"    ' Define title
                Response = MsgBox(Msg, Style, Title)
                If Response = vbOK Then    ' User chose Ok
                    Exit Function
                End If
            End If
        Next
    End Function

End Class

我正在尝试使用结构作为参数之一来调用函数“ CheckData”，但似乎无法弄清楚。注意：相对于VB来说，这是新手，请保持柔和。

Answer 1

首先，请启用严格选项。您可以在以下位置找到此设置工具菜单->选项->项目和解决方案-> VB默认值。这样可以避免在运行时出现错误。

Function CheckData(Stock As Object, txtSku As TextBox, product() As Object, txtName As TextBox)

Stock As Object

将变量与结构命名为一个好主意。参数的模式是“变量名”为“数据类型”。您的结构是公开的，因此可以通过每种方法看到。尝试远离对象作为数据类型。您永远不会在函数中使用变量Stock，所以这是不必要的。记住Stock是一个局部变量。它与称为股票的结构无关。它是对象类型。

txtSku As TextBox

看来txtSku是您表单上的TextBox。不必将其传递给您的函数，因为该函数可以直接访问它。

product() As Object

product()是一个表单级别变量，因此对于该表单的所有方法均可见。没必要。

txtName As TextBox

与＃2相同-不必要

Function需要一个DataType

私有函数CheckData（）为布尔值

和函数主体中的返回

Return True

它不必是Boolean，可以是任何类型。这只是一个例子。由于未返回任何内容，因此应为Sub过程。

Dim product(300) As Stock

声明具有301个元素的数组，索引从0到300。在vb.net中，数组声明为product（UBound）或上限。这为301库存结构保留了一些内存。使用List（Of T）T代表Type可能更好。因此，您的列表将是

Dim product as New List(Of Stock)

通过这种方式，您不必担心列表中有多少项。

现在进入您的btnSave_Click 创建Stock
的新实例
将stck设置为新库存

设置一些属性

stck.prodSku = txtSKU.Text

添加到产品列表

product.Add(stck)

重复使用相同的变量，将其设置为Stock的新实例

stck = New Stock
stck.prodSKU = "af"
procuct.Add(stck)

在这种情况下和大多数情况下，无需使用Call关键字。

CheckData()

返回Sub CheckData（）nee函数的主体。请在线查看注释和解释。

Public Structure Stock
    Dim prodSKU As String
    Dim sizeAmt As Integer
    Dim prodName As String
    Dim category As String
    Dim sellPrice As Decimal
    Dim buyPrice As Decimal
End Structure

'A plural name helps identify this as a collection
Private products As New List(Of Stock)

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    'Create a new Stock object
    Dim stck As New Stock
    stck.prodSKU = txtSKU.Text
    'Add the Stock object to the list
    products.Add(stck)
    stck = New Stock
    stck.prodSKU = "af"
    products.Add(stck)
End Sub

Private Sub CheckData()
    For Each item As Stock In products
        'These values will be overwritten on every iteration of the loop
        txtSku.Text = item.prodSKU
        txtName.Text = item.prodName
        'Well this is kind of silly you just set these properties so of course it is true!
        'If txtSku.Text = item.prodSKU Or txtName.Text = product(Index).prodName Then
        'With Option Strict uninitiated varaibles must have a type
        'Dim Msg, Style, Title, Response
        'the variable is assigned a value so the compiler now knows the type
        Dim Msg = "That SKU/Product Name already exists, enter another"    ' Define message.
        Dim Title = "Repeated Saved Data"    ' Define title
        'Since the user can only click OK this loop will only go once
        Dim Response As DialogResult = MessageBox.Show(Msg, Title, MessageBoxButtons.OK)
        If Response = vbOK Then    ' User chose Ok
            Exit Sub
        End If
    Next
End Sub

在VB中以结构为参数调用函数

1 个答案: