Question

我有一个面板（Panel1），两个组合框（ComboBox1，ComboBox2）和一个按钮（Button1）都采用相同的形式（{{1} }）。

单击按钮时：

Form1

Private Sub Button1_Click(sender As Object, e As EventArgs) Dim a as String = ComboBox1.SelectedValue() & Combobox2.SelectedValue() AddUserControl(a) End Sub的值是实例a的外部用户控件的名称。我可以使用以下方法在p1k1中向p1k1添加名为Panel1的外部用户控件吗？

Form1

我该怎么做才能使这项工作？

通常我会使用：

Private Sub AddUserControl(ByVal a As String)
    Panel1.Controls.Add(a)
End Sub

Answer 1

您需要使用reflection来执行此操作。像这样：

    Private Sub AddUserControl(ByVal a As String)
        Dim controlType As Type = Type.GetType(a)
        If controlType Is Nothing Then
            Throw New ArgumentException(String.Format("""{0}"" is not a valid type.  Type names are case sensitive.", a))
        ElseIf Not controlType.IsSubclassOf(GetType(Control)) Then
            Throw New ArgumentException(String.Format("""{0}"" does not inherit from Control.  Only Controls can be added to the control collection.", a))
        End If

        Dim newControl As Control = Activator.CreateInstance(controlType)
        If newControl Is Nothing Then
            Throw New ArgumentException(String.Format("Unspecified error when creating control of type ""{0}"".", a))
        End If
        Panel1.Controls.Add(newControl)
    End Sub

Answer 2

我终于找到了答案......

Private Sub AddUserControl（ByVal a As String）
  Dim nmspace As String =“mynamespace”
  Dim t As Type = Assembly.GetExecutingAssembly（）。GetType（nmspace＆amp;“。”＆amp; a）
  Dim o As Control = Activator.CreateInstance（t）
  Panel1.Controls.Add（O）
  结束Sub

通过名称调用外部用户控件

2 个答案: