Question

我有一个WPF应用程序，我有MainWindow.xalm，MainWindow.xalm.cs和一个名为Utilities.cs的类文件。在MainWindow.xaml中，我创建了一个带有子菜单的侧面菜单。我根据用户选择的内容启用和禁用侧边菜单。我在Utilities.cs类中创建了代码，以启用或禁用，具体取决于是传递true还是false。在MainWindow.xaml.cs中，我引用了Utilities.cs类，如下所示：

NBFoodPantry.Utilities nbuUtilities = new NBFoodPantry.Utilities();

在Utilities.cs文件中，我引用了MainWindow组件，如下所示：

NBFoodPantry.MainWindow nbMainWindow = new MainWindow();

这是我的MainWindow.xaml.cs文件的开头：

namespace NBFoodPantry
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    /// 
    public partial class MainWindow : Window
    {
        SqlConnection sqlConn;
        string strErrorLogPath, strErrorLogFile, strVCClientIDSelected, strFCClientIDSelected = string.empty;
        string strVCName, strFCName, strVCButtonType, strDBInstance = string.empty;
        bool blnRowSelected, blnUpdateGridLoaded;;
        bool[] blnUpdateFields = new bool[9];
        DataRowView drvRow;
        PrintDocument printDocument1 = new PrintDocument();
        PrintPreviewDialog printPreviewDialog = new PrintPreviewDialog();
        bool isWeeklyReportViewerLoaded, isPhoneReportViewerLoaded, isDependentAgeReportViewerLoaded;
       BindingSource dataBindingSource = new BindingSource();

       NBFoodPantry.Utilities nbuUtilities = new NBFoodPantry.Utilities();

       public class Client
       {
           public string Name { get; set; }

           public DataGridRow DGRow { get; set; }
       }



        #region MainWindow
        public MainWindow()
        {

这是我的Utilities.cs文件的开头：

namespace NBFoodPantry
{
    public class Utilities
    {
        NBFoodPantry.MainWindow nbMainWindow = new MainWindow();

以下是我为从MainWindow引用子菜单而创建的几个例程：

public void EnableAddMenu(bool blnStatus)
    {
        nbMainWindow.miAdd.IsEnabled = blnStatus;
    }


    public void EnableAddSubMenus(bool blnStatus)
    {

        nbMainWindow.smiAddCheckinDate.IsEnabled = blnStatus;
        nbMainWindow.smiAddMonthlyVisitDate.IsEnabled = blnStatus;
        nbMainWindow.smiAddCardIssueDate.IsEnabled = blnStatus;
        nbMainWindow.smiAddDependent.IsEnabled = blnStatus;
        nbMainWindow.smiAddNote.IsEnabled = blnStatus;
    }

现在，当我尝试运行该程序时，我收到此消息：

 "An unhandled exception of type 'System.StackOverflowException' occurred in mscorlib.dll"

在这行代码上：

PrintPreviewDialog printPreviewDialog = new PrintPreviewDialog();

知道为什么我现在得到这个错误？我该如何处理这些错误？代码工作得很好，直到我将重复的代码移到Utilities.cs。

Answer 1

您可以在Utilities类中注入对已经初始化的MainWindow类实例的引用，而不是在Utilities类中创建MainWindow类的新实例。您将需要对此特定实例的引用，以便能够启用和禁用其中的任何控件。请参阅以下示例代码。

<强> MainWindow.xaml.cs：

public partial class MainWindow : Window
{
    SqlConnection sqlConn;
    string strErrorLogPath, strErrorLogFile, strVCClientIDSelected, strFCClientIDSelected = string.empty;
    string strVCName, strFCName, strVCButtonType, strDBInstance = string.empty;
    bool blnRowSelected, blnUpdateGridLoaded;;
    bool[] blnUpdateFields = new bool[9];
    DataRowView drvRow;
    PrintDocument printDocument1 = new PrintDocument();
    PrintPreviewDialog printPreviewDialog = new PrintPreviewDialog();
    bool isWeeklyReportViewerLoaded, isPhoneReportViewerLoaded, isDependentAgeReportViewerLoaded;
    BindingSource dataBindingSource = new BindingSource();

    public class Client
    {
        public string Name { get; set; }

        public DataGridRow DGRow { get; set; }
    }

    NBFoodPantry.Utilities nbuUtilities;
    public MainWindow()
    {
        InitializeComponent();
        nbuUtilities = new NBFoodPantry.Utilities(this);
    }
}

<强> Utilities.cs：

public class Utilities
{
    NBFoodPantry.MainWindow nbMainWindow;

    public Utilities(NBFoodPantry.MainWindow mainWindow)
    {
        nbMainWindow = mainWindow;
    }
}

Answer 2

我正在采用＃BradleyDotNET的方法。我在Utilities.cs文件中将我的代码更改为：

public void EnableAddMenu(bool blnStatus)
    {
        ((MainWindow)System.Windows.Application.Current.MainWindow).miAdd.IsEnabled = blnStatus;
    }


    public void EnableAddSubMenus(bool blnStatus)
    {
        ((MainWindow)System.Windows.Application.Current.MainWindow).smiAddCheckinDate.IsEnabled = blnStatus;
        ((MainWindow)System.Windows.Application.Current.MainWindow).smiAddMonthlyVisitDate.IsEnabled = blnStatus;
        ((MainWindow)System.Windows.Application.Current.MainWindow).smiAddCardIssueDate.IsEnabled = blnStatus;
        ((MainWindow)System.Windows.Application.Current.MainWindow).smiAddDependent.IsEnabled = blnStatus;
        ((MainWindow)System.Windows.Application.Current.MainWindow).smiAddNote.IsEnabled = blnStatus;
    }

这就是现在，我也在研究MVVC的方法来学习正确的方法。

如何在单独的类中访问MainWindow XAML组件？

2 个答案: