VBNET 更改列表框中的图像路径时出错

Question

我被困住了，不知道该怎么办，我正在尝试制作一个image viewer，并将image的所有路径按文件夹放在一个listbox中，然后当我尝试在index 2列表中选择时，我得到错误，它说"内存不足异常">

这是我的代码

Public Class Form1
Dim myimg As Array
Private Sub img_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles img.Click
    If FolderBrowserDialog1.ShowDialog = DialogResult.OK Then
        myimg = IO.Directory.GetFiles(FolderBrowserDialog1.SelectedPath)
        ListBox1.Items.AddRange(myimg)
        ListBox1.SelectedIndex = 0
    End If
End Sub
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
    Me.Refresh()
    Me.BackgroundImage = Nothing
    Me.BackgroundImage = Image.FromFile(ListBox1.SelectedItem.ToString)
End Sub
Private Sub min_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles min.Click
    Me.WindowState = FormWindowState.Maximized
End Sub
Private Sub max_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles max.Click
    Me.WindowState = FormWindowState.Normal
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class

错误位于此处

Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
    Me.Refresh()
    Me.BackgroundImage = Nothing
    Me.BackgroundImage = Image.FromFile(ListBox1.SelectedItem.ToString)
End Sub

，请帮忙谢谢:)

Answer 1

列表中可能没有有效的图像文件。 查找异常：

Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) _
                                          Handles ListBox1.SelectedIndexChanged
  Try
    If ListBox1.SelectedIndex > -1 Then
      Me.BackgroundImage = Image.FromFile(ListBox1.SelectedItem.ToString)
    End If
  Catch ex As OutOfMemoryException
    'not a valid image file
  End Try
End Sub

要筛选列表，您可以执行以下操作：

Using fbd As New FolderBrowserDialog
  If fbd.ShowDialog = DialogResult.OK Then
    myimg = IO.Directory.GetFiles(fbd.SelectedPath).Where( _
                         Function(x) x.ToLower.EndsWith("bmp") _
                                  Or x.ToLower.EndsWith("png")).ToArray
    ListBox1.Items.AddRange(myimg)
    ListBox1.SelectedIndex = 0
  End If
End Using

Answer 2

这是您的问题可能开始的地方：

Private Sub img_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles img.Click
  If FolderBrowserDialog1.ShowDialog = DialogResult.OK Then
     myimg = IO.Directory.GetFiles(FolderBrowserDialog1.SelectedPath)
     ListBox1.Items.AddRange(myimg)
     ListBox1.SelectedIndex = 0
  End If
End Sub

因此，在他们从您的ListBox中进行选择之前：

Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
  Me.Refresh()
  Me.BackgroundImage = Nothing
  Me.BackgroundImage = Image.FromFile(ListBox1.SelectedItem.ToString)
End Sub

为什么不将ListBox中显示的图像大小限制为5MB，例如：

Private Sub img_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles img.Click
  If FolderBrowserDialog1.ShowDialog = DialogResult.OK Then
     myimg = IO.Directory.GetFiles(FolderBrowserDialog1.SelectedPath)
     For Each imgfile As String In myimg
         Dim allowedImgFile As New System.IO.FileInfo(imgfile)
         If ((allowedImgFile.Length / 1024) <= 5) Then
            ListBox1.Items.Add(imgfile)
         End If
     Next
     ListBox1.SelectedIndex = 0
  End If
End Sub

您需要通知用户，只有 5MB 或更小(或您喜欢的任何大小(的图像才会显示在列表中。