Question

我在文件（目录或任何类型的文件）上使用拖放列表视图。当我从桌面拖放My Computer或Bin时，会发生NullReferenceException。

我只想跳过此元素（在日志文本框中或显示内容中显示一些文本）。我不知道如何实现这一目标。我不知道Desktop中的MyComputer元素是哪种对象。

这是对这个主题逻辑毫无用处的代码：

private void Directories_ListView_DragDrop(object sender, DragEventArgs e)
    {

        string[] DroppedDirectories = (string[]) e.Data.GetData(DataFormats.FileDrop,false); //array of dd files paths
        try
        {
            foreach (var directory in DroppedDirectories) // here Exception  occurs this loop process all dragged and drop files 
            {
                ListViewItem Dir = new ListViewItem(Path.GetFileNameWithoutExtension(directory));
                //Place for some checking Logic
                if (GetDir.IsDirectory(directory))
                {
                   (.....);// Doing some things
                }
                else
                    LogList.Items.Add(DateTime.Now + ": Entry " + Dir.Text + " is not a directory");

            }
        }
        catch(Exception) // it only stops app from crashing, 
        {
            LogList.Items.Add(DateTime.Now + "One of elements was Mycomputer or Bin, process stopped ");
        }
    }

Answer 1

感谢LarsTech和Abion47，您的解决方案是在这种情况下包装拖放代码：

if (e.Data.GetData(DataFormats.FileDrop, false) != null)
{
    string[] DroppedDirectories = (string[]) e.Data.GetData(DataFormats.FileDrop,false);

    foreach(string directory in DroppedDirectories)
    {
        try
        {
            ListViewItem Dir = new ListViewItem(Path.GetFileNameWithoutExtension(directory));
            //Rest of code
        }
        catch(Exception ex)
        {
            LogList.Items.Add(DateTime.Now + ": Entry " + directory + " is not a directory");
        }
    }
}

拖放异常。桌面物件

1 个答案: