WPF和MVVM:从文本框中获取值并将其发送到ViewModel

Question

当我按下按钮时,我正试图获得两个Texbox的值(我正在模拟一个登录窗口).按钮中指定的命令正确触发,但我不知道如何获取文本框的值来执行"登录".

这是我的ViewModel:

class LoginViewModel : BaseViewModel
{   
    public LoginViewModel()
    {

    }

    private DelegateCommand loginCommand;
    public ICommand LoginCommand
    {
        get
        {
            if (loginCommand == null)
                loginCommand = new DelegateCommand(new Action(LoginExecuted),
                               new Func<bool>(LoginCanExecute));
                return loginCommand;
            }
        } 

    public bool LoginCanExecute()
    {
        //Basic strings validation...
        return true;
    }
    public void LoginExecuted()
    {
        //Do the validation with the Database.
        System.Windows.MessageBox.Show("OK");
    } 
}

这是观点:

 <Grid DataContext="{StaticResource LoginViewModel}">

            <TextBox x:Name="LoginTxtBox" HorizontalAlignment="Left" Height="23" Margin="34,62,0,0" Width="154" />
            <PasswordBox x:Name="PasswordTxtBox" HorizontalAlignment="Left" Height="23" Margin="34,104,0,0" Width="154"/>
            <Button x:Name="btnAccept"
            HorizontalAlignment="Left" 
            Margin="34,153,0,0" 
            Width="108" 
            Content="{DynamicResource acceptBtn}" Height="31" BorderThickness="3"
            Command="{Binding LoginCommand}"/>

如果有人能帮忙......我将无限感激.

Answer 1

通常,您将TextBox.Text属性绑定到ViewModel上的属性.这样,值存储在ViewModel中,而不是View中,并且没有"获取"所需的值.

class LoginViewModel : BaseViewModel
{ 
    //...
    private string userName;
    public string UserName
    {
        get { return this.userName; }
        set 
        {
           // Implement with property changed handling for INotifyPropertyChanged
           if (!string.Equals(this.userName, value))
           {
               this.userName = value;
               this.RaisePropertyChanged(); // Method to raise the PropertyChanged event in your BaseViewModel class...
           }
        } 
    }

    // Same for Password...

然后,在你的XAML中,你会做类似的事情:

<TextBox Text="{Binding UserName}" HorizontalAlignment="Left" Height="23" Margin="34,62,0,0" Width="154" />
<PasswordBox Text="{Binding Password}" HorizontalAlignment="Left" Height="23" Margin="34,104,0,0" Width="154"/>

此时,LoginCommand可以直接使用本地属性.