C# · 12月 24, 2021

c# – WPF将窗口标题绑定到ViewModel属性

我试图将窗口标题绑定到具有Title属性的viewmodel.下面是MainWindow XAML: <Window x:Class=”MyProject.View.MainWindow” xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation” xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml” xmlns:vm=”clr-namespace:MyProject.viewmodel;assembly=MyProject.viewmodel” Title=”{Binding Path=Title}” Height=”350″ Width=”525″ DataContext=”{Binding Source={StaticResource mainWindowviewmodel}}”> <Window.Resources> <vm:MainWindow x:Key=”mainWindowviewmodel”/> </Window.Resources>…</Window>

当我尝试运行它,我得到以下异常“提供值System.Windows.StaticResourceExtension”抛出一个异常.行号和位置指向DataContext属性,内部异常状态“找不到名为mainWindowviewmodel的资源.

以下是View Model的代码:

namespace MyProject.viewmodel{ public class MainWindow : INotifyPropertyChanged { #region Fields private const string TitlebarPrefixString = “My Project”; private string title = TitlebarPrefixString; public string Title { get { return this.title; } // End getter set { this.title = value; OnPropertyChanged(“Title”); } // End setter } // End property protected virtual void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = PropertyChanged; if (handler != null) { handler(this,new PropertyChangedEventArgs(propertyName)); } // End if } // End method public event PropertyChangedEventHandler PropertyChanged; } // End class} // End namespace

我的理论是在试图将标题绑定到属性之后加载资源.抛出异常时,Window的Resources属性为空.

是唯一的解决方案来设置DataContext在代码背后吗?我可以让这个工作,但我宁愿把它保存在XAML.

解决方法 您可以尝试使用属性元素语法设置DataContext: <Window x:Class=”MyProject.View.MainWindow” xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation” xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml” xmlns:vm=”clr-namespace:MyProject.viewmodel;assembly=MyProject.viewmodel” Title=”{Binding Path=Title}” Height=”350″ Width=”525″><Window.Resources> <vm:MainWindow x:Key=”mainWindowviewmodel”/></Window.Resources><Window.DataContext> <StaticResourceExtension ResourceKey=”mainWindowviewmodel”/></Window.DataContext>

这应该在xaml解析器将在资源字典设置完成后执行StaticResourceExtension.

但是我认为甚至可以直接设置DataContext,而不将其声明为资源:

<Window x:Class=”MyProject.View.MainWindow” xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation” xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml” xmlns:vm=”clr-namespace:MyProject.viewmodel;assembly=MyProject.viewmodel” Title=”{Binding Path=Title}” Height=”350″ Width=”525″><Window.DataContext> <vm:MainWindow x:Key=”mainWindowviewmodel”/></Window.DataContext>