wpf mvvm 登录界面代码

WPF MVVM模式的登录界面代码可以分为视图(View)、模型(Model)和视图模型(ViewModel)三部分。

首先是视图(View)部分，该部分主要负责呈现应用程序用户界面，以及与用户之间的交互。下面是一个简单的登录视图的XAML界面代码：

<Window x:Class="WpfApplication1.LoginView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="LoginView" Height="200" Width="350">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Row="0" Grid.Column="0" Text="用户名：" VerticalAlignment="Center"/>
        <TextBox Grid.Row="0" Grid.Column="1" Text="{Binding Username, UpdateSourceTrigger=PropertyChanged}" Width="150" Margin="5"/>
        <TextBlock Grid.Row="1" Grid.Column="0" Text="密码：" VerticalAlignment="Center"/>
        <PasswordBox Grid.Row="1" Grid.Column="1" Password="{Binding Password, UpdateSourceTrigger=PropertyChanged}" Width="150" Margin="5"/>
        <CheckBox Grid.Row="2" Grid.Column="1" Content="记住密码" VerticalAlignment="Center" IsChecked="{Binding RememberMe, Mode=TwoWay}" Margin="5"/>
        <Button Grid.Row="3" Grid.ColumnSpan="2" Content="登录" Command="{Binding LoginCommand}" Width="100" Margin="5" HorizontalAlignment="Right"/>
        <TextBlock Grid.Row="4" Grid.ColumnSpan="2" Text="{Binding ErrorMessage}" Foreground="Red" Margin="5"/>
    </Grid>
</Window>

接着是模型(Model)部分，该部分主要定义应用程序的数据模型以及相关操作，例如存储用户名密码等信息，以及验证登录信息是否正确。下面是一个简单的登录模型的C#代码：

public class LoginModel
{
    private readonly IDictionary<string, string> _users = new Dictionary<string, string>
    {
        {"user1", "password1"},
        {"user2", "password2"},
        {"user3", "password3"}
    };

    public bool ValidateUser(string username, string password)
    {
        if (_users.ContainsKey(username) && _users[username] == password)
        {
            return true;
        }
        return false;
    }
}

最后是视图模型(ViewModel)部分，该部分主要完成视图(View)与模型(Model)之间的数据绑定和交互。下面是一个简单的登录视图模型的C#代码：

public class LoginViewModel : INotifyPropertyChanged
{
    private readonly LoginModel _model = new LoginModel();

    private string _username;

    public string Username
    {
        get { return _username; }
        set
        {
            if (_username != value)
            {
                _username = value;
                RaisePropertyChanged("Username");
            }
        }
    }

    private string _password;

    public string Password
    {
        get { return _password; }
        set
        {
            if (_password != value)
            {
                _password = value;
                RaisePropertyChanged("Password");
            }
        }
    }

    private bool _rememberMe;

    public bool RememberMe
    {
        get { return _rememberMe; }
        set
        {
            if (_rememberMe != value)
            {
                _rememberMe = value;
                RaisePropertyChanged("RememberMe");
            }
        }
    }

    private string _errorMessage;

    public string ErrorMessage
    {
        get { return _errorMessage; }
        set
        {
            if (_errorMessage != value)
            {
                _errorMessage = value;
                RaisePropertyChanged("ErrorMessage");
            }
        }
    }

    private RelayCommand _loginCommand;

    public RelayCommand LoginCommand
    {
        get
        {
            if (_loginCommand == null)
            {
                _loginCommand = new RelayCommand(
                    () =>
                    {
                        if (_model.ValidateUser(_username, _password))
                        {
                            ErrorMessage = "";
                            MessageBox.Show("登录成功！");
                        }
                        else
                        {
                            ErrorMessage = "用户名或密码错误！";
                        }
                    },
                    () =>
                    {
                        return !string.IsNullOrEmpty(_username) && !string.IsNullOrEmpty(_password);
                    }
                );
            }
            return _loginCommand;
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

以上就是WPF MVVM模式的简单登录界面代码。