1

我是 WPF 和 MVVM 的新手。我尝试使用 MVVM 创建登录窗口，我成功创建了。
这是 Login.xmal 代码。

<Button x:Name="btnLogin" Content="Login" HorizontalAlignment="Left" Margin="51,0,0,10" 
            VerticalAlignment="Bottom" Width="124" Height="57" Grid.Column="1" 
            CommandParameter="{Binding ElementName=txtPassword}" 
            Command="{Binding LoginCommand}"
            >           
    </Button>

    <Button x:Name="btnClose" Content="Close" HorizontalAlignment="Left" Margin="180,0,0,10" 
        VerticalAlignment="Bottom" Width="124" Height="57" Grid.Column="1"    Command="{Binding ExitCommand}">

    </Button>

    <Label Content="User Name" Margin="10,74,0,0" VerticalAlignment="Top" Height="49" 
           VerticalContentAlignment="Center" Grid.Column="1" HorizontalAlignment="Left" Width="130"/>

    <TextBox x:Name="txtUserName" HorizontalAlignment="Right" Height="49" Margin="0,74,10,0" 

             TextWrapping="Wrap"  VerticalAlignment="Top" Width="185" 
             VerticalContentAlignment="Center" Grid.Column="1" FontSize="18">
        <TextBox.Text>
            <Binding Path="Username" Mode="OneWayToSource">
                <Binding.ValidationRules>
                    <ExceptionValidationRule></ExceptionValidationRule>
                </Binding.ValidationRules>
            </Binding>
        </TextBox.Text>
    </TextBox>

    <Label Content="Password" Margin="10,128,0,0" VerticalAlignment="Top" Height="49" 
           VerticalContentAlignment="Center" Grid.Column="1" HorizontalAlignment="Left" Width="130"/>
    <PasswordBox x:Name="txtPassword" HorizontalAlignment="Right"
             Height="49" Margin="0,128,10,0"
          VerticalAlignment="Top" Width="185" 
        VerticalContentAlignment="Center" Grid.Column="1" FontSize="18">

    </PasswordBox>

在此之后，我创建了 viewModeBase.cs 类，我在其中实现了 INotifyPropertyChanged，这包含在 LoginViewModel.cs 中......这是 LoginViewModel.cs 代码

public class LoginViewModel : ViewModelBase
{
    private string m_username;
    public string Username
    {
        get { return m_username; }
        set
        {
            m_username = value;
            OnPropertyChanged("Username");

        }
    }

    private string m_password;
    public string Password
    {
        get { return m_password; }
        set
        {
            m_password = value;
            OnPropertyChanged("Password");
        }
    }
    private DelegateCommand exitCommand;

    public ICommand ExitCommand
    {
        get
        {
            if (exitCommand == null)
            {
                exitCommand =new DelegateCommand(Exit);
            }
            return exitCommand;
        }
    }

    private void Exit()
    {
        Application.Current.Shutdown();
    }

    public LoginViewModel()
    {

    }

    private DelegateCommand<object> loginCommand;
    public ICommand LoginCommand
    {
        get
        {
            if (loginCommand == null)
            {
                loginCommand = new DelegateCommand<object>(Login);
            }
            return loginCommand;
        }
    }



    public void Login(object pPasswordBox)
    {
        try
        {
            if (string.IsNullOrEmpty(Username))
            {
                MessageBox.Show("Username cannot be blank.");                    
                return;
            }

            if (string.IsNullOrEmpty(((PasswordBox)pPasswordBox).Password))
            {
                MessageBox.Show("Password cannot be blank.");                
                return;
            }

            dlUsers odlUsers = new dlUsers();
            bool lResult = odlUsers.UserAuthentication(clsGymManagment.ConnectionString, Username, 
                ((((PasswordBox)pPasswordBox).Password)));
            if (lResult)
            {
                ///TODO: Need code to Hide Login Window and Open New XAML.....
            }
            else
            {
                MessageBox.Show("Username/Password is wrong.");                   
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }         
}

因为我想隐藏 LOGIN.XAML 文件并打开 UI.XAML 文件..（UI.XAML 你可以考虑任何 XAML 窗口。）......如果你能帮助我在 UI 上的 Usercontrol 之间导航，那也会很有帮助。 XAML

4

2 回答 2

2

您需要从单独的代码块（例如 App.xaml.cs）控制登录窗口。将 app.xaml 设置为调用代码而不是显示窗口。

让 App_Startup 创建 LoginViewModel，新建一个表单，将表单的数据上下文设置为您的 ViewModel 并显示它。

对表单的更新将更新 ViewModel，当它关闭时，它将控制权返回给您的调用代码。

登录.xaml.cs

    private void btnOk_Click(object sender, RoutedEventArgs e)
    {
        if (anything incorrect)
        {
            MessageBox.Show("Enter a username and password");
        }
        else
            DialogResult = true;
    }

应用程序.xaml.cs

Login.DataContext = LoginViewModel;

if (Login.ShowDialog() ?? false)
{
   //Check the LoginViewModel for a correct password. 
}
于 2013-05-28T06:19:01.837 回答
1

幸运的是，当您在应用程序内的不同页面中移动时隐藏和显示不同控件的功能已经为您编写好了。请参阅http://msdn.microsoft.com/en-us/library/ms750478.aspx。

导航窗口非常强大，并且可以很容易地进行蒙皮以提供完全不同的外观。见http://alski.net/post/2012/01/13/WPF-Wizards-part-2-Glass.aspx

于 2013-05-28T06:24:30.967 回答