空路径名称不合法

Question

我有一个"保存"按钮,所以当用户点击时,它将保存xml文件(xml序列化).这里使用了savefiledialog,当我按下取消而不选择任何文件时出现"参数异常"并说"空路径名称不合法".我该如何处理这个例外？即使没有在savefiledialog中选择任何路径,我希望表单保持不变.非常感谢.

我的savefiledialog片段:

private void SaveButton_Click(object sender, RoutedEventArgs e)
{
        string savepath;
        SaveFileDialog DialogSave = new SaveFileDialog();
        // Default file extension
        DialogSave.DefaultExt = "txt";
        // Available file extensions
        DialogSave.Filter = "XML file (*.xml)|*.xml|All files (*.*)|*.*";
        // Adds a extension if the user does not
        DialogSave.AddExtension = true;
        // Restores the selected directory, next time
        DialogSave.RestoreDirectory = true;
        // Dialog title
        DialogSave.Title = "Where do you want to save the file?";
        // Startup directory
        DialogSave.InitialDirectory = @"C:/";
        DialogSave.ShowDialog();
        savepath = DialogSave.FileName;
        DialogSave.Dispose();
        DialogSave = null;
        ...
        using (Stream savestream = new FileStream(savepath, FileMode.Create))
        {
                XmlSerializer serializer = new XmlSerializer(typeof(FormSaving));
                serializer.Serialize(savestream, formsaving);
        }

}

我的参数异常发生在这一行:

using (Stream savestream = new FileStream(savepath, FileMode.Create))
{
        XmlSerializer serializer = new XmlSerializer(typeof(FormSaving));
        serializer.Serialize(savestream, formsaving);
}

Answer 1

这里的问题是您不关心"保存"对话框的结果,即使用户单击"取消",您也会尝试保存.你应该改变代码看起来像这样:

...
DialogSave.InitialDirectory = @"C:/";
if( DialogSave.ShowDialog() == DialogResult.OK )
{
  savepath = DialogSave.FileName;
  DialogSave = null;
  ...
  using (Stream savestream = new FileStream(savepath, FileMode.Create))
  {
     XmlSerializer serializer = new XmlSerializer(typeof(FormSaving));
     serializer.Serialize(savestream, formsaving);
  }
}
DialogSave.Dispose();