Question

我是mvvm模式的新手，当我尝试将属性绑定到文本框时，我总是在输出调试器中出现此错误： “System.Windows.Data错误：BindingExpression路径错误：在'DesktopContainerViewModel''System.String'上找不到'MainView'属性'（HashCode = -115914272）.BindingExpression：Path ='MainView'DataItem ='DesktopContainerViewModel'（ HashCode = -115914272）;目标元素是'System.Windows.Controls.TextBlock'（Name =''）;目标属性是'Text'（类型'System.String'）..“

Xaml Code :
<UserControl x:Class="PlanNetApp.UI.DesktopContainerView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:b="clr-namespace:PlanNetApp.Controls.Behaviors;assembly=PlanNetApp.Controls"
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
    xmlns:ctrl="clr-namespace:PlanNetApp.Controls.Custom;assembly=PlanNetApp.Controls"
    xmlns:conv="clr-namespace:PlanNetApp.Controls.Convertors;assembly=PlanNetApp.Controls"
    xmlns:v="clr-namespace:PlanNetApp.UI.Views"
    xmlns:vb="clr-namespace:PlanNetApp.UI.Views.Boq"
    xmlns:ctrlui="clr-namespace:PlanNetApp.UI.Controls"
    xmlns:vp="clr-namespace:PlanNetApp.UI.Views.Project"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:m="clr-namespace:PlanNetApp.UI"
    mc:Ignorable="d"
     DataContext="DesktopContainerViewModel"
    d:DataContext="{d:DesignData Source=C:\\RASEMP_Code\\DROP2\\Desktop\\DesktopV1\\PlanNetTestApp\\PlanNetApp.UI\\DesignTime\\DesktopContainerSample.xaml}"    
    d:DesignHeight="600" d:DesignWidth="800"
             FlowDirection="LeftToRight"
             >

    <UserControl.Resources>
        <conv:BooleanToBusyIndicatorStatus x:Key="BooleanToBusyIndicatorStatusConver"/>
        <conv:IsEqualParameterToVisibility x:Key="IsEqualParameterToVisibilityConverter"/>
        <conv:IsEqualParameterToBool x:Key="IsEqualParameterToBool" />
        <conv:EnumValues x:Key="EnumValuesConverter" />
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot" >

        <Grid.Background>
            <LinearGradientBrush StartPoint="0.5, 0" EndPoint="0.5,1">
                <GradientStop Color="#FF4D4D4D" Offset="0"/>
                <GradientStop Color="#FF2B2B2B" Offset="0.599"/>
                <GradientStop Color="#FF0B0B0B" Offset="1"/>
            </LinearGradientBrush>
        </Grid.Background>
        <Rectangle
            b:Texture.ImageSource="../Images/Textures/Wood.png"
            Opacity="0.485"
            />

        <Grid x:Name="main" >
            <Grid.RowDefinitions>
                <RowDefinition Height="50"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
            </Grid.RowDefinitions>

            <Grid Height="50" VerticalAlignment="Top">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="80"></ColumnDefinition>
                    <ColumnDefinition Width="Auto"></ColumnDefinition>
                    <ColumnDefinition Width="20"></ColumnDefinition>
                    <ColumnDefinition Width="Auto"></ColumnDefinition>
                    <ColumnDefinition Width="20"></ColumnDefinition>
                    <ColumnDefinition Width="Auto"></ColumnDefinition>
                    <ColumnDefinition Width="20"></ColumnDefinition>
                    <ColumnDefinition Width="Auto"></ColumnDefinition>
                </Grid.ColumnDefinitions>

                <ctrl:HoverText Text="Exit"
                                   ForGroundText="#9d9c9c"
                                   Grid.Column="1"></ctrl:HoverText>
                <ctrl:HoverText Text="Somebody"
                                   ForGroundText="#9d9c9c"
                                   Grid.Column="3"></ctrl:HoverText>
                <ctrl:HoverText Text="Support"
                                   ForGroundText="#9d9c9c"
                                   Grid.Column="5"></ctrl:HoverText>


     *<TextBlock Text="{Binding Path=MainView}"    Grid.Column="7"/>*



            </Grid>

        </Grid>

    </Grid>
</UserControl>

后面没有代码（mvvm模式:)） vieModel看起来像：

viewmodel.cs：

public enum DesktopMainView
    {
          None,
          Desktop,
          Apps
    }

    public enum AppMainView
    {
        None,
        Projects,
        Prices
    }

    public class DesktopContainerViewModel : AnnotatedViewModel
    {
        #region MView property
        public const String MViewPropertyName = "MView";

        private DesktopMainView p_MView;

        public DesktopMainView MView
        {
            get
            {
                return p_MView;
            }
            set
            {
                if (p_MView != value)
                {
                    p_MView = value;
                    _notifyPropertyChanged(MViewPropertyName);
                }
            }
        }
        #endregion

        #region MainView property
        public const String MainViewPropertyName = "MainView";

        private String p_MainView;

        public String MainView
        {
            get
            {
                return p_MainView;
            }
            set
            {
                if (p_MainView != value)
                {
                    p_MainView = value;
                    _notifyPropertyChanged(MainViewPropertyName);
                }
            }
        }
        #endregion


        #region AppMainView property
        public const String AppMainViewPropertyName = "AppMainView";

        private AppMainView p_AppMainView;

        public AppMainView AppMainView
        {
            get
            {
                return p_AppMainView;
            }
            set
            {
                if (p_AppMainView != value)
                {
                    p_AppMainView = value;
                    _notifyPropertyChanged(AppMainViewPropertyName);
                }
            }
        }
        #endregion

        #region NavigateToProjectDetailsCommand property
        public const String NavigateToProjectDetailsCommandPropertyName = "NavigateToProjectDetailsCommand";

        private RelayCommand p_NavigateToProjectDetailsCommand;

        public RelayCommand NavigateToProjectDetailsCommand
        {
            get
            {
                return p_NavigateToProjectDetailsCommand;
            }
            set
            {
                if (p_NavigateToProjectDetailsCommand != value)
                {
                    p_NavigateToProjectDetailsCommand = value;
                    _notifyPropertyChanged(NavigateToProjectDetailsCommandPropertyName);
                }
            }
        }
        #endregion

        private void ExecuteNavigateToProjectDetailsCommand(object param)
        {
            FrameworkElement anchor = param as FrameworkElement;
            if (MView == DesktopMainView.Desktop)
            {

                MView = DesktopMainView.Apps;
                AppMainView = AppMainView.Projects;

            }
        }

        public DesktopContainerViewModel()
        {
            NavigateToProjectDetailsCommand = new RelayCommand(ExecuteNavigateToProjectDetailsCommand);
            MView = DesktopMainView.Desktop;
            AppMainView = AppMainView.None;
            MainView = MView.ToString();
        }

        public override void Cleanup()
        {
            throw new NotImplementedException();
        }

        protected override void OnAnnotationDirty()
        {
            throw new NotImplementedException();
        }

        public override string AnnotationTitle()
        {
            throw new NotImplementedException();
        }
    }

在我的viemodel中有一个名为MainView的属性！另外我正在使用一个designTime Binding并且使用这个绑定我可以看到绑定作品.. 可能是什么问题??

Answer 1

问题在于：

DataContext="DesktopContainerViewModel"

尝试在代码隐藏中设置这样的DataContext：

this.DataContext = new DesktopContainerViewModel();

如何在Silverlight中解决BindingExpression路径错误？

1 个答案: