我正在编写简单的应用程序。 UI有两个文本框，用于用户名和密码，以及用于提交信息的按钮。我想使用路由命令而不是buttonclick事件。
用户名只能包含字母数字字符，如果用户输入任何其他特殊字符，则应显示一个标签，表示输入了无效字符。所以我想根据在Username文本框字段上完成的验证来绑定该标签的可见性和内容。
以下是我所制作的代码，但它没有按预期工作。任何人都可以帮助我在哪里做错了吗？
在我的主窗口
下面using System.Windows;
using System.Windows.Input;
using System.ComponentModel;
namespace ExcelUtility
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
ViewModel viewModelObj = new ViewModel();
public MainWindow()
{
InitializeComponent();
}
void navigatePageExecuted(object target, ExecutedRoutedEventArgs e)
{
SubmitUserDetails(txtUserName.Text + ";" + txtPassword);
}
void navigatePageCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
if (!string.IsNullOrWhiteSpace(txtUserName.Text))
{
viewModelObj.Username = txtUserName.Text;
}
e.CanExecute = viewModelObj.VaidUserName; }
private void SubmitUserDetails(string credentials)
{
this.Cursor = Cursors.Wait;
prgValidate.Visibility = Visibility.Visible;
MainGrid.IsEnabled = false;
BackgroundWorker worker = new BackgroundWorker();
worker.DoWork += worker_DoWork;
worker.RunWorkerCompleted += worker_RunWorkerCompleted;
worker.RunWorkerAsync(credentials);
}
void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
prgValidate.Visibility = Visibility.Collapsed;
string Result = (string)e.Result;
MessageBox.Show(Result); //Here I need to call some other functions based on return value for simplicity i have changed
}
void worker_DoWork(object sender, DoWorkEventArgs e)
{
string[] credentials = e.Argument.ToString().Split(';');
e.Result = viewModelObj.validateCredentials(credentials[0], credentials[1]);
}
}
}
这是我的xaml
<Window x:Class="ExcelUtility.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:ExcelUtility"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:BoolToVisibleOrHidden x:Key="BoolToVisibilityConverter"/>
</Window.Resources>
<Window.CommandBindings>
<CommandBinding Command="{x:Static local:CommandsLibrary.navigatePageCommand}" Executed="navigatePageExecuted" CanExecute="navigatePageCanExecute"/>
</Window.CommandBindings>
<Grid Name="MainGrid">
<TextBlock Height="23" HorizontalAlignment="Left" Margin="40,44,0,0" Name="tbUserName" Text="Username" VerticalAlignment="Top" />
<TextBox Height="23" HorizontalAlignment="Left" Margin="136,42,0,0" Name="txtUserName" VerticalAlignment="Top" Width="163" Text="{Binding Username, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="138,19,0,0" Name="tbNotify" Text="{Binding Notification, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="161" Visibility="{Binding NotVaidUserName,Converter={StaticResource BoolToVisibilityConverter}}" />
<TextBox Height="23" HorizontalAlignment="Left" Margin="138,98,0,0" Name="txtPassword" VerticalAlignment="Top" Width="161" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="44,107,0,0" Name="tbPassword" Text="Password" VerticalAlignment="Top" Width="65" />
<Button Command="{x:Static local:CommandsLibrary.navigatePageCommand}" Content="Submit" Height="23" HorizontalAlignment="Left" Margin="172,167,0,0" Name="btnSubmit" VerticalAlignment="Top" Width="109" />
<ProgressBar Height="24" IsIndeterminate="True" Visibility="Collapsed" HorizontalAlignment="Left" Margin="52,232,0,0" Name="prgValidate" VerticalAlignment="Top" Width="257" />
</Grid>
</Window>
这是我的viewModel
using System;
using System.Text.RegularExpressions;
using System.ComponentModel;
using System.Windows.Data;
using System.Windows;
namespace ExcelUtility
{
public class ViewModel
{
public event PropertyChangedEventHandler PropertyChanged;
private bool _notVaidUserName;
public bool NotVaidUserName
{
get { return _notVaidUserName; }
set
{
_notVaidUserName = value;
RaisePropertyChanged("NotVaidUserName");
}
}
private string notification;
public string Notification
{
get
{
return notification;
}
set
{
if (notification != value)
{
notification = value;
RaisePropertyChanged("Notification");
}
}
}
private string username;
public string Username
{
get
{
return username;
}
set
{
if (username != value)
{
username = value;
NotVaidUserName = VaidateUserName(username);
RaisePropertyChanged("Username");
}
}
}
public bool VaidateUserName(string strUsername)
{
bool bValidUserName = false;
if (!string.IsNullOrWhiteSpace(strUsername))
{
if (new Regex(@"^[a-zA-Z0-9]*$").IsMatch(strUsername))
{
bValidUserName = true;
if (strUsername.Length > 7)
{
Notification = "Max allowed key length is 6";
bValidUserName = false;
}
}
else
{
Notification = "No special characters allowed";
}
}
return bValidUserName;
}
public string validateCredentials(string Username, string Password)
{
return "Valid Credentials";
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
class BoolToVisibleOrHidden : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
object returnvalue = new object();
returnvalue = (bool)value ? Visibility.Visible : parameter != null ? Visibility.Collapsed : Visibility.Hidden;
return returnvalue;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return (Visibility)value == Visibility.Visible;
}
}
}
答案 0 :(得分：0)
首先定义两个属性，如下所示：
private bool isValid = true;
public bool IsValid
{
get
{
return isValid;
}
set
{
if (isValid != value)
{
isValid = value;
OnPropertyChanged("IsValid");
}
}
}
private string username;
public string Username
{
get
{
return username;
}
set
{
if(username != value)
{
username = value;
IsValid = ValidateForSpecialCharacters(username);
OnPropertyChanged("Username");
}
}
}
然后将它们绑定到您的xaml，如下所示：
<TextBlock Text="Username contains special characters."
Visibility="{Binding IsValid,Converter={StaticResource BoolToVisibilityConverter}}" />
<TextBox Text="{Binding Username, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />
PS：不要忘记实现BoolToVisibility转换器类和ValidateForSpecialCharacter方法。我想你可以自己处理。顺便说一句，如果我是你，我会用ValidationRule代替这种方式。
希望得到这个帮助。
答案 1 :(得分：0)
您必须创建一个boolToVis转换器，它将False转换为折叠，将True转换为可见。
在此之后，您可以将bool值绑定到项目的visibility属性。
这是转换器（您可以将它放在一个文件中并从xaml调用它）：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
namespace yourNamespace.ViewModel
{
[ValueConversion(typeof(bool), typeof(bool))]
public class InverseBooleanConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
if (value is bool)
{
return !(bool)value;
}
return value;
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
if (value is bool)
{
return !(bool)value;
}
return value;
}
}
}
然后，从你的xaml，在文件的开头：
<UserControl.Resources>
<BooleanToVisibilityConverter x:Key="BoolToVis"/>
</UserControl.Resources>
或者如果您使用窗口：
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BoolToVis"/>
</Window.Resources>
然后，最后，在你的textBox中：
<dxe:TextEdit Visibility="{Binding YOURBOOLFLAG, Converter={StaticResource BoolToVis}}" EditValue="TextHere"/>
（TextEdit是一个devexpress元素;你也可以用同样的方式使用经典的textBox）
这样，当您看到文本不正确时，可以将bool标志设置为false并隐藏元素。
答案 2 :(得分：0)
您可以简单地实现一个检查用户名字符的转换器，如下所示：
class VisibilityConverter:IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var rgx = new Regex(@"^[a-zA-Z0-9]*$");
if (value == null) return Visibility.Hidden;
return (rgx.IsMatch(value.ToString()))?Visibility.Hidden:Visibility.Visible;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
不要忘记将转换器添加到窗口资源
<Window.Resources>
<conv:VisibilityConverter x:Key="VisibilityConverter"/>
</Window.Resources>
最后在UI中使用该转换器来检查在textBox中输入的字符串
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Text="Username" Grid.Column="0" Grid.Row="0"/>
<TextBlock Text="Password" Grid.Column="0" Grid.Row="1"/>
<TextBox Grid.Column="1" Grid.Row="0" Text="{Binding Username,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
<TextBox Grid.Column="1" Grid.Row="1" Text="{Binding Password,Mode=TwoWay}"/>
<Button Content="login" IsEnabled="{Binding Username,Converter={StaticResource VisibilityConverter},Mode=TwoWay}" Grid.Column="1" Grid.Row="2"/>
<TextBlock Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" Text="invalid characters entered" VerticalAlignment="Center" HorizontalAlignment="Center" Visibility="{Binding Username,Converter={StaticResource VisibilityConverter}}"></TextBlock>
</Grid>