在 ViewModel 问题中绑定到对象属性答案

【问题标题】：Binding to Object Property in ViewModel issue在 ViewModel 问题中绑定到对象属性
【发布时间】：2016-06-21 13:04:04
【问题描述】：

不知道为什么这不起作用...下面是我的 ViewModel，它设置为我的 View DataContext。

public class UploadViewModel : CrudVMBase
    {
        #region Commands
        public CommandVM UploadButtonCommand { get; set; } =
            new CommandVM
            {
                CommandDisplay = "Perform Upload",
                IconGeometry = App.Current.Resources["pencil30"] as Geometry,
                Message = new CommandMessage { Command = CommandType.UploadFromCamera }
            };
        #endregion End Commands

        #region Public Properties
        UploadInitiation UploadObject { get; set; } = new UploadInitiation();
        #endregion End Public Properties

        public UploadViewModel()
        {

        }

下面是 UploadInitiation 类

public class UploadInitiation : Common.NotifyUIBase
    {
        #region Public Properties
            public ObservableCollection<UploadStep> Steps { get; set; } = new ObservableCollection<UploadStep>();
            public int UploadProgress { get; set; } = 45;
            public string UploadTask { get; set; } = "Idle...";
            public bool UploadEnabled { get; set; } = false;
            public bool UploadBegin { get; set; } = false;
        #endregion END Public Properties

        public UploadInitiation()
        {
            // Populate steps required, ensure upload returns UI updates
            Steps.Add(new UploadStep { Message = "Seperate upload to new thread...", Complete = false, Error = null });
            Steps.Add(new UploadStep { Message = "Generate new file names...", Complete = false, Error = null });
            Steps.Add(new UploadStep { Message = "Render Thumbnails, add to database...", Complete = false, Error = null });
            Steps.Add(new UploadStep { Message = "Move images ready for print...", Complete = false, Error = null });
        }
    }

这是我的绑定，你可以看到我试图绑定到UploadProgress 属性。

<ProgressBar Style="{StaticResource CircularProgress}" Width="180" Value="{Binding UploadObject.UploadProgress}" />

这是错误

System.Windows.Data 错误：40：BindingExpression 路径错误：在“对象”“UploadViewModel”上找不到“UploadObject”属性 (哈希码=33902366)'。 BindingExpression:Path=UploadObject.UploadProgress; DataItem='UploadViewModel' (HashCode=33902366);目标元素是 '进度条'（名称=''）；目标属性是“值”（类型“双”）

【问题讨论】：

标签： c# wpf mvvm datacontext access-modifiers

【解决方案1】：

您需要将属性的范围声明为public，否则默认为私有。因此在绑定时是不可见的。

public UploadInitiation UploadObject { get; set; } = new UploadInitiation();

【讨论】：

我真是个白痴！我确信我已经做到了……我什至读了很多遍！谢谢！