Question

我正在使用Extended WPF Toolkit中的IntegerUpDown控件，我也在使用Caliburn.Micro和PostSharp。我试图让它根据我的ViewModel中的属性设置控件的最大值和最小值。

我可以获得Minumum或Maximum值，但不能同时使用。所以我显然做了一些只允许最后一个属性绑定的东西。这是我的AppBootstrapper课程：

using Caliburn.Micro;
using System.Windows;
using Xceed.Wpf.Toolkit;

namespace Test {
    public class AppBootstrapper : Bootstrapper<MainViewModel>{

        static AppBootstrapper() {
            var baseBindProperties = ViewModelBinder.BindProperties;

            ConventionManager.AddElementConvention<FrameworkElement>(IntegerUpDown.MinimumProperty, "Minimum", "ValueChanged");
            ViewModelBinder.BindProperties =
                (frameWorkElements, viewModels) => {
                    foreach (var frameworkElement in frameWorkElements) {
                        var propertyName = frameworkElement.Name + "Minimum";
                        var property = viewModels
                                .GetPropertyCaseInsensitive(propertyName);
                        if (property != null) {
                            var convention = ConventionManager
                                .GetElementConvention(typeof(FrameworkElement));
                            ConventionManager.SetBindingWithoutBindingOverwrite(
                                viewModels,
                                propertyName,
                                property,
                                frameworkElement,
                                convention,
                                convention.GetBindableProperty(frameworkElement));
                        }
                    }
                    return baseBindProperties(frameWorkElements, viewModels);
                };

            ConventionManager.AddElementConvention<FrameworkElement>(IntegerUpDown.MaximumProperty, "Maximum", "ValueChanged");
            ViewModelBinder.BindProperties =
                (frameWorkElements, viewModels) => {
                    foreach (var frameworkElement in frameWorkElements) {
                        var propertyName = frameworkElement.Name + "Maximum";
                        var property = viewModels
                                .GetPropertyCaseInsensitive(propertyName);
                        if (property != null) {
                            var convention = ConventionManager
                                .GetElementConvention(typeof(FrameworkElement));
                            ConventionManager.SetBindingWithoutBindingOverwrite(
                                viewModels,
                                propertyName,
                                property,
                                frameworkElement,
                                convention,
                                convention.GetBindableProperty(frameworkElement));
                        }
                    }
                    return baseBindProperties(frameWorkElements, viewModels);
                };
        }
    }
}

在上面的示例中，设置了最大值，但不是最小值。如果我交换它们，以便最后设置最小绑定，则最小值有效，但最大值无效。我在这里做错了什么？

为了完整起见，如果你想运行它，这里是MainView.xaml：

<Window x:Class="Test.MainView"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <TextBox Name="Text"/>
        <xctk:IntegerUpDown Name="Number"/>
        <Button Name="Click" Height="25" Content="Test"/>
    </StackPanel>
</Window>

和MainViewModel.cs：

using Caliburn.Micro;
using PostSharp.Patterns.Model;
using System;

namespace Test {

    [NotifyPropertyChanged]
    public class MainViewModel : Screen {

        public string Text { get; set; }

        public int Number { get; set; }

        public int NumberMaximum { get; set; }

        public int NumberMinimum { get; set; }

        public MainViewModel()
            : base() {
            this.NumberMinimum = 50;
            this.NumberMaximum = 100;
            this.Number = 75;
        }

        public void Click() {
            Console.WriteLine("Text: '"+this.Text+"'");
            Console.WriteLine("Number: '"+this.Number+"'");
        }

        protected void OnPropertyChanged(string propertyName) {
            NotifyOfPropertyChange(propertyName);
        }
    }
}

Answer 1

我想到的是

ConventionManager.GetElementConvention(typeof(FrameworkElement));

并没有真正返回正确的约定，而是总是返回添加的最后一个约定。我还认为我在静态构造函数中将它们设置在错误的位置。所以我把它移到了一个覆盖的Configure方法中。我的AppBootstrapper课现在看起来像：

using Caliburn.Micro;
using System.Windows;
using Xceed.Wpf.Toolkit;

namespace Test {
    public class AppBootstrapper : Bootstrapper<MainViewModel>{

        protected override void Configure() {
            base.Configure();

            //setup the conventions
            var valueConvention = ConventionManager.AddElementConvention<FrameworkElement>(IntegerUpDown.ValueProperty, "Value", "ValueChanged");
            var maximumConvention = ConventionManager.AddElementConvention<FrameworkElement>(IntegerUpDown.MaximumProperty, "Maximum", "ValueChanged");
            var minimumConvention = ConventionManager.AddElementConvention<FrameworkElement>(IntegerUpDown.MinimumProperty, "Minimum", "ValueChanged");

            //bind the properties
            var baseBindProperties = ViewModelBinder.BindProperties;
            ViewModelBinder.BindProperties =
                (frameWorkElements, viewModels) => {

                    foreach (var frameworkElement in frameWorkElements) {
                        var valuePropertyName = frameworkElement.Name;
                        var valueProperty = viewModels
                                .GetPropertyCaseInsensitive(valuePropertyName);

                        if (valueProperty != null) {
                            ConventionManager.SetBindingWithoutBindingOverwrite(
                                    viewModels,
                                    valuePropertyName,
                                    valueProperty,
                                    frameworkElement,
                                    valueConvention,
                                    valueConvention.GetBindableProperty(frameworkElement));
                        }

                        var maxPropertyName = frameworkElement.Name + "Maximum";
                        var maxProperty = viewModels
                                .GetPropertyCaseInsensitive(maxPropertyName);

                        if (maxProperty != null) {
                            ConventionManager.SetBindingWithoutBindingOverwrite(
                                    viewModels,
                                    maxPropertyName,
                                    maxProperty,
                                    frameworkElement,
                                    maximumConvention,
                                    maximumConvention.GetBindableProperty(frameworkElement));
                        }

                        var minPropertyName = frameworkElement.Name + "Minimum";
                        var minProperty = viewModels
                                .GetPropertyCaseInsensitive(minPropertyName);

                        if (minProperty != null) {
                            ConventionManager.SetBindingWithoutBindingOverwrite(
                                viewModels,
                                minPropertyName,
                                minProperty,
                                frameworkElement,
                                minimumConvention,
                                minimumConvention.GetBindableProperty(frameworkElement));
                        }
                    }

                    return baseBindProperties(frameWorkElements, viewModels);
                };

        }
    }
}

使用Calburn.Micro和扩展WPF工具包？

1 个答案: