Question

我的Windows窗体应用程序中有一个Telerik Tabbed PageView，我可以通过双击它们来编辑标签的标题，从而启动文本编辑器。以下潜艇负责更改标签 - 检查编辑的标签是否为空白：

Private Sub ViewElement_EditorInitialized(sender As Object, e As UI.RadPageViewEditorEventArgs)
    AddHandler MountingSystemTabControl.ViewElement.ActiveEditor.Validating, AddressOf ActiveEditor_Validating
    AddHandler MountingSystemTabControl.ViewElement.ActiveEditor.Validated, AddressOf ActiveEditor_Validated
    AddHandler MountingSystemTabControl.ViewElement.ActiveEditor.ValidationError, AddressOf ActiveEditor_ValidationError
End Sub

Private Sub ActiveEditor_Validating(sender As Object, e As CancelEventArgs)
    Dim editor As UI.RadPageViewElement.PageViewItemTextEditor = TryCast(sender, UI.RadPageViewElement.PageViewItemTextEditor)
    If editor IsNot Nothing AndAlso MountingSystemTabControl.ViewElement.ActiveEditor.Value = String.Empty Then
        e.Cancel = True
    End If
End Sub

Private Sub ActiveEditor_ValidationError(sender As Object, e As UI.ValidationErrorEventArgs)
    RadMessageBox.Show("Array label can't be empty!", "Error", MessageBoxButtons.OK, RadMessageIcon.[Error])
End Sub

Private Sub ActiveEditor_Validated(sender As Object, e As EventArgs)
    RadMessageBox.Show("Array label has been successfully updated!", "Information", MessageBoxButtons.OK, RadMessageIcon.Info)
End Sub

此外，我的Form_Load事件中有这一行：

AddHandler MountingSystemTabControl.ViewElement.EditorInitialized, AddressOf ViewElement_EditorInitialized

现在问题是，每当我运行代码时，在MessageBox向我显示＆＃34; 数组标签已成功更新后！＆＃34;消息，抛出 NullReference异常，似乎即使使用应用程序事件处理程序也无法捕获它！破解代码后，Visual Studio将此行作为异常来源引用我：

RadMessageBox.Show("Array label has been successfully updated!", "Information", MessageBoxButtons.OK, RadMessageIcon.Info)

这让我感到困惑，因为我无法找到该行中的任何内容（当然有些东西，但我不知道是什么）。

Call Stack screenshot

Main idea of the code

Answer 1

由于内存服务......我认为RadMessageBox会调用Parent参数。

试试这个：

RadMessageBox.Show(Me, "Array label has been successfully updated!", "Information", MessageBoxButtons.OK, RadMessageIcon.Info)

Answer 2

通过更新到2015年WinForms的Telerik UI（版本 2015.1.225 ）＆＃39;

解决了该问题

无法找出原因＆＃39; NullReferenceException＃39;被扔了

2 个答案: