Question

我正在使用MvvmLight编写演示程序。我想要的是将View中的TextBox绑定到Model中的属性。绑定似乎正确，因为我可以显示我的输入MessageBox的TextBox。问题是在ViewModel中将属性设置为string.Empty后，View中的文本框保持不变。

Model LoginToMisInfo.cs

using GalaSoft.MvvmLight;

namespace MvvmLight1.Model
{
    /// <summary>
    /// This class contains properties that a View can data bind to.
    /// <para>
    /// See http://www.galasoft.ch/mvvm
    /// </para>
    /// </summary>
    public class LoginToMisInfo : ViewModelBase
    {
        /// <summary>
        /// Initializes a new instance of the LoginToMisInfo class.
        /// </summary>
        public LoginToMisInfo()
        {
        }
        private string userName;

        public string UserName
        {
            get
            {
                return userName;
            }
            set
            {
                userName = value;
            }
        }
    }
}

ViewModel LoginToMis.cs

using GalaSoft.MvvmLight;
using MvvmLight1.Model;
using System.ComponentModel;
using GalaSoft.MvvmLight.Command;
using System.Windows.Input;
using System.Windows;

namespace MvvmLight1.ViewModel
{
    /// <summary>
    /// This class contains properties that a View can data bind to.
    /// <para>
    /// See http://www.galasoft.ch/mvvm
    /// </para>
    /// </summary>
    public class LoginToMis : ViewModelBase
    {
        /// <summary>
        /// Initializes a new instance of the LoginToMis class.
        /// </summary>
        public LoginToMis()
        {
            //CommandCancel = new RelayCommand(() => ConfirmExecute(), () => true);
            CommandConfirm = new RelayCommand(() => ConfirmExecute(), () => true);
            CommandClear = new RelayCommand(() => ClearExecuate(), () => true);
        }

        LoginToMisInfo LoginInfo = new LoginToMisInfo();
        public event PropertyChangedEventHandler PropertyChanged;

        public string UserName
        {
            get
            {
                return LoginInfo.UserName;
            }
            set
            {
                LoginInfo.UserName = value;
                if(this.PropertyChanged!=null)
                {
                    this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs("LoginInfo.UserName"));
                }
            }
        }

        public ICommand CommandCancel { get; private set; }
        public ICommand CommandConfirm { get; private set; }
        public ICommand CommandClear { get; private set; }

        private void ConfirmExecute()
        {
            MessageBox.Show(UserName);
        }

        private void ClearExecuate()
        {
            UserName = string.Empty;
        }
    }
}

View：

DataContext

DataContext="{Binding MyLoginToMis, Source={StaticResource Locator}

（我已在LoginToMis注册ViewModelLocator）

TextBox

<TextBox Grid.Row="0" Grid.Column="1"
MinWidth="100" 
Text="{Binding UserName,UpdateSourceTrigger=PropertyChanged}"/>

'按钮'

<Button Content="Confirm" MinWidth="150" MinHeight="80"
Margin="50,0,50,0" IsDefault="True" 
Command="{Binding CommandConfirm}"/>

<Button Content="Clear" MinWidth="150" MinHeight="80"
Margin="50,0,50,0" Command="{Binding CommandClear}"/>

基本上，我在Model中创建了一个类，并在ViewModel中包装了它的一个实例，然后我将ViewModel中的属性绑定到View中的TextBox中{1}}。在TextBox中输入一些单词并单击确认后，将弹出一个MessageBox并在TextBox中显示输入。单击清除，然后单击TextBox不要更新。任何想法？

Answer 1

您应该为UserName属性提高属性更改通知。

您可以使用RaisePropertyChanged提供的MvvmLight方法提出属性更改通知。 ViewModelBase类提供的方法，该方法继承ObservableObject：

RaisePropertyChanged("UserName");

TextBox不会在MvvmLight中更新

1 个答案: