Question

我的vb程序有问题，因为我的结构数组不会填充使用split命令拆分的文本文件中的数据。困惑。任何建议都会很棒。代码如下。

Imports System.IO

Public Class Form1

    Public Structure ScavRecord
        Public latitude As String
        Public longitude As String
        Public message As String
        Public encrypted As String
    End Structure

    Dim Scav(4) As ScavRecord
    Dim nextScav As Integer

    Private Sub btnView_Click(sender As Object, e As EventArgs) Handles btnView.Click

        Dim read As New StreamReader("F:\Higher Computing Science\Assignment\files for candidates\messages.txt")
        nextScav = 0
        Do
            Dim temp As String = read.ReadLine()
            Dim seperated As String() = temp.Split(",")


            Scav(nextScav).latitude = seperated(0)
            Scav(nextScav).longitude = seperated(1)
            Scav(nextScav).message = seperated(2)
            nextScav = nextScav + 1
            ListBox.Items.Add(Scav(nextScav).latitude)
            ListBox.Items.Add(Scav(nextScav).longitude)
            ListBox.Items.Add(Scav(nextScav).message)

        Loop Until read.EndOfStream()


    End Sub



End Class

Answer 1

结构是值类型，这意味着当您从某个地方获取结构类型的值时，您将获得一个副本。这包括访问值类型数组中的项目，就像您使用Scav(nextScav)一样。所以这一行：

Scav(nextScav).latitude = seperated(0)

首先评估Scav(nextScav)并在ScavRecord处为您提供nextScav的副本。然后为其latitude指定一个值。然后将副本丢弃。

要解决此问题，您需要分配整个值：

Dim record As New ScavRecord()
record.latitude = separated(0)
record.longitude = separated(1)
record.message = separated(2)

Scav(nextScav) = record

结构和分裂

1 个答案: