Visual Studio 2022中ListBox仅显示文件名时读取文件报错求助

问题现象 #

使用Visual Studio 2022开发的小程序，将指定目录下的.txt文件加载到ListBox时仅显示无路径无扩展名的文件名，选中ListBox项读取内容到TextBox时触发System.IO.FileNotFoundException，错误提示找不到类似C:DistancebinDebugfriend的文件——原因是程序直接用ListBox中存储的纯文件名作为路径去读取，默认从当前运行目录查找，而非原文件所在目录，且缺少.txt扩展名。

解决方案 #

方法1：存储完整路径，自定义ListBox显示文本

通过ListBoxItem的Tag属性存储文件完整路径，同时设置Text属性显示纯文件名，既满足显示需求，又能准确获取文件路径。

修改加载文件的代码：

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles btnCarica.Click
    Dim dirpath As String = FolderBrowserDialog1.SelectedPath '选择目标目录
    '仅筛选目录下的.txt文件，避免加载无关文件
    Dim cerca() As String = Directory.GetFiles(dirpath, "*.txt")
    lsbNomi.Items.Clear() '清空ListBox原有内容
    For Each x As String In cerca
        Dim listItem As New ListBoxItem()
        listItem.Text = Path.GetFileNameWithoutExtension(x) '显示无路径无扩展名的文件名
        listItem.Tag = x '存储文件完整路径
        lsbNomi.Items.Add(listItem)
    Next        
End Sub

修改ListBox点击读取的代码：

Private Sub ListBox1_Click(sender As Object, e As EventArgs) Handles lsbNomi.Click
    If lsbNomi.SelectedItem Is Nothing Then
        MessageBox.Show("Selezionare un File esistente!", "ATTENZIONE!", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        Exit Sub
    End If
    '从Tag中获取完整文件路径
    Dim fullFilePath As String = DirectCast(lsbNomi.SelectedItem, ListBoxItem).Tag.ToString()
    Dim leggi As StreamReader = File.OpenText(fullFilePath)
    txtDati.Text = "" '先清空TextBox原有内容
    While leggi.Peek <> -1
        txtDati.Text += leggi.ReadLine() + vbCrLf
    End While
    leggi.Close()
    '根据行数设置TextBox可用状态
    Dim lineCount As Integer = txtDati.Lines.Count
    txtDati.Enabled = lineCount > 28
    lsbNomi.Enabled = False
End Sub

方法2：保存目录路径，读取时拼接完整路径

将用户选择的目录路径存储为全局变量，读取时拼接纯文件名与.txt扩展名，生成完整文件路径。

1. 定义全局变量存储目录路径：

Private selectedDirectory As String = String.Empty

2. 修改加载文件的代码：

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles btnCarica.Click
    selectedDirectory = FolderBrowserDialog1.SelectedPath '保存选择的目录路径
    Dim cerca() As String = Directory.GetFiles(selectedDirectory, "*.txt")
    lsbNomi.Items.Clear()
    For Each x As String In cerca
        lsbNomi.Items.Add(Path.GetFileNameWithoutExtension(x))
    Next        
End Sub

3. 修改ListBox点击读取的代码：

Private Sub ListBox1_Click(sender As Object, e As EventArgs) Handles lsbNomi.Click
    If String.IsNullOrEmpty(lsbNomi.Text) Then
        MessageBox.Show("Selezionare un File esistente!", "ATTENZIONE!", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        Exit Sub
    End If
    '用Path.Combine拼接完整路径，自动处理路径分隔符
    Dim fullFilePath As String = Path.Combine(selectedDirectory, lsbNomi.SelectedItem.ToString() & ".txt")
    '提前判断文件是否存在，避免异常
    If Not File.Exists(fullFilePath) Then
        MessageBox.Show("文件不存在！", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error)
        Exit Sub
    End If
    Dim leggi As StreamReader = File.OpenText(fullFilePath)
    txtDati.Text = ""
    While leggi.Peek <> -1
        txtDati.Text += leggi.ReadLine() + vbCrLf
    End While
    leggi.Close()
    Dim lineCount As Integer = txtDati.Lines.Count
    txtDati.Enabled = lineCount > 28
    lsbNomi.Enabled = False
End Sub

关键注意点 #

• 加载文件时筛选.txt类型：避免加载非目标文件，减少后续读取异常
• 使用Path.Combine拼接路径：比直接字符串拼接更安全，自动适配不同系统的路径分隔符
• 读取前判断文件状态：提前检查文件是否存在，提升程序稳定性

内容的提问来源于stack exchange，提问作者Maurizio Vignazzi