Question

我需要在visual basic中编写这个小程序，但是我面临一个问题，即我无法在运行时更改颜色或添加列表形式的文本文件。

这是我不想做的事情的图片

http://i62.tinypic.com/30tghh0.png

这是我到目前为止编写的代码，

    Public Class Form1

    Private Sub NewToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NewToolStripMenuItem.Click
        Dim listBox1 As New System.Windows.Forms.ListBox
        listBox1.Text = "New List"
        listBox1.Location = New Point(25, 25)
        listBox1.Size = New Size(380, 280)
        Me.Controls.Add(listBox1)
        OpenToolStripMenuItem.Enabled = True
        SaveToolStripMenuItem.Enabled = True
        SaveAsToolStripMenuItem.Enabled = True
        CloseToolStripMenuItem.Enabled = True
        EditToolStripMenuItem.Enabled = True

    End Sub

    Private Sub ExirToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExirToolStripMenuItem.Click
        End

    End Sub


    Private Sub OpenToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OpenToolStripMenuItem.Click

        If (OpenFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK) Then
            Dim myfile As String = OpenFileDialog1.FileName
            Dim allLines As String() = File.ReadAllLines(myfile)
            For Each line As String In allLines
                ListBox1.Items.Add(line)
            Next
        End If
    End Sub
End Class

您看到的问题出在OpenToolStripMenuItem子行中，行ListBox1.Items.Add(line)

是没有listbox1，因为还没有创建。与颜色相同，保存和其余部分。

所以，请帮我解决一下。

Answer 1

将ListBox1的声明移到Class级别：

Public Class Form1

    Private ListBox1 As System.Windows.Forms.ListBox

    Private Sub NewToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NewToolStripMenuItem.Click
        ListBox1 = New System.Windows.Forms.ListBox
        ...
    End Sub

    ...

End Class

*但为什么要在运行时创建它呢？您可以在设计时添加它并将Visible（）属性设置为False。单击“新建”按钮时，将Visible（）更改为True。除非你每次都需要创建一个新的ListBox，所以你有多个？如果是这样，他们将如何布置？...

在运行时创建列表框，并在运行时通过菜单更改其颜色

1 个答案: