我的应用程序中有多个视图模型,并在 ViewModelLocator mvvm light 中绑定/使用它们。我在 DailyActivities.xaml 页面之一上完成了按钮。但是当我单击它时,它在 ViewModelLocator 中出现错误,例如“对象引用未设置为对象的实例”。和控制来到这一行:
公共静态无效ClearActivities(){_activities.Cleanup();//这里出错_activities = null; }
这是 ViewModelLocator 中 DailyActivityViewModel 的代码:
私有静态活动视图模型_活动;
public static ActivitiesViewModel ActivitiesStatic
{
get
{
if (_activities == null)
{
CreateActivities();
}
return _activities;
}
}
/// <summary>
/// Gets the ViewModelPropertyName property.
/// </summary>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
"CA1822:MarkMembersAsStatic",
Justification = "This non-static member is needed for data binding purposes.")]
public ActivitiesViewModel Activities
{
get
{
return ActivitiesStatic;
}
}
/// <summary>
/// Provides a deterministic way to delete the ViewModelPropertyName property.
/// </summary>
public static void ClearActivities()
{
_activities.Cleanup(); --Error here
_activities = null;
}
/// <summary>
/// Provides a deterministic way to create the ViewModelPropertyName property.
/// </summary>
public static void CreateActivities()
{
if (_activities == null)
{
_activities = new ActivitiesViewModel();
}
}
请建议?
谢谢