Silverlight IDataErrorInfo message does not show in custom control's textbox - silverlight

Question

I created a custom password box user control which is able to show and hide the password. It just swaps out the standard password box with a textbox which is bound to the same password string property. It all works fine but now my data validation errors are no more shown, although they are being generated correctly in the background. Here's the xaml from my user control:
<UserControl x:Class="Controls.EAPPasswordBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400" x:Name="_root">
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Top">
<PasswordBox x:Name="pwdBox" Password="{Binding Password, Mode=TwoWay,ValidatesOnDataErrors=True}" />
<TextBox x:Name="txtBox" Text="{Binding Password, Mode=TwoWay,ValidatesOnDataErrors=True}" />
</StackPanel>
</Grid>
Here's how I use it in a view:
<local:EAPPasswordBox x:Name="pwdBox"
Grid.Column="1" Grid.Row="0" Grid.ColumnSpan="2" Password="{Binding password,Mode=TwoWay, ValidatesOnDataErrors=True}" ShowText="{Binding showPassword,Mode=TwoWay}"></local:EAPPasswordBox>
in the Parent view's viewmodel we implemented IDataErrorInfo like this:
public string this[string columnName]
{
get
{
string Result = "";
switch(columnName.ToLower())
{
case "password":
{
Result = Validatepassword();
break;
}
case "password2":
{
Result = Validatepassword2();
break;
}
default:
{
Result = this.ValidateStringValue(columnName);
break;
}
}
return Result;
}
}
Now when I enter text in the custom password box, the validation logic is called just fine but it's not displayed. Do I have to adjust my user control for this?
EDIT: Here's the code behind of my passwordbox:
public partial class EAPPasswordBox : UserControl, INotifyPropertyChanged
{
public bool ShowText
{
get { return (bool)GetValue(ShowTextProperty); }
set {
SetValue(ShowTextProperty, value);
if (value == true)
{
this.pwdBox.Visibility = System.Windows.Visibility.Collapsed;
this.txtBox.Visibility = System.Windows.Visibility.Visible;
}
else
{
this.pwdBox.Visibility = System.Windows.Visibility.Visible;
this.txtBox.Visibility = System.Windows.Visibility.Collapsed;
}
}
}
public string Password
{
get { return (string)GetValue(PasswordProperty); }
set { SetValue(PasswordProperty, value); }
}
private Visibility _PwdBoxVisibility;
public Visibility PwdBoxVisibility
{
get { return _PwdBoxVisibility; }
set
{
_PwdBoxVisibility = value; NotifyPropertyChanged("PwdBoxVisibility");
}
}
private Visibility _TxtBoxVisibility;
public Visibility TxtBoxVisibility
{
get { return _TxtBoxVisibility; }
set
{
_TxtBoxVisibility = value; NotifyPropertyChanged("TxtBoxVisibility");
}
}
public static readonly DependencyProperty PasswordProperty =
DependencyProperty.Register("Password", typeof(string), typeof(EAPPasswordBox), null);
public static readonly DependencyProperty ShowTextProperty =
DependencyProperty.Register("ShowText", typeof(bool), typeof(EAPPasswordBox), new PropertyMetadata(OnShowTextPropertyChanged));
public EAPPasswordBox()
{
InitializeComponent();
this.pwdBox.SetBinding(PasswordBox.PasswordProperty, new System.Windows.Data.Binding() { Source = this, Path = new PropertyPath("Password"), Mode = BindingMode.TwoWay,ValidatesOnDataErrors=true });
this.txtBox.SetBinding(TextBox.TextProperty, new System.Windows.Data.Binding() { Source = this, Path = new PropertyPath("Password"), Mode = BindingMode.TwoWay, ValidatesOnDataErrors=true });
this.ShowText = false;
}
private static void OnShowTextPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
EAPPasswordBox passwordBox = d as EAPPasswordBox;
if (passwordBox != null)
{
passwordBox.ShowText=(bool)e.NewValue;
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
}
2nd Edit: It would also help if someone would just explain to me the basics of binding properties of usercontrols in the xaml of a parent window/control. I dont quite understand why the usercontrol doesnt get the property changed events of the corresponding parent views viewmodel properties since it is bound to those via xaml.

Answer 1

Here's my solution at last. Since I realized that the DataContext of the user control automatically is the ViewModel of the parent view, I dumped the binding of the Password dependency property completely. I introduced a new parameter in the control which has to be set to the password property of the parent view model. I then use this string to do a manual binding of the textbox and the password box in the loaded event of the control. Here's my code:
public partial class EAPPasswordBox : UserControl, INotifyPropertyChanged
{
public bool ShowText
{
get { return (bool)GetValue(ShowTextProperty); }
set {
SetValue(ShowTextProperty, value);
if (value == true)
{
this.pwdBox.Visibility = System.Windows.Visibility.Collapsed;
this.txtBox.Visibility = System.Windows.Visibility.Visible;
}
else
{
this.pwdBox.Visibility = System.Windows.Visibility.Visible;
this.txtBox.Visibility = System.Windows.Visibility.Collapsed;
}
}
}
public string PasswordPropertyName { get; set; }
private Visibility _PwdBoxVisibility;
public Visibility PwdBoxVisibility
{
get { return _PwdBoxVisibility; }
set
{
_PwdBoxVisibility = value; NotifyPropertyChanged("PwdBoxVisibility");
}
}
private Visibility _TxtBoxVisibility;
public Visibility TxtBoxVisibility
{
get { return _TxtBoxVisibility; }
set
{
_TxtBoxVisibility = value; NotifyPropertyChanged("TxtBoxVisibility");
}
}
public static readonly DependencyProperty ShowTextProperty =
DependencyProperty.Register("ShowText", typeof(bool), typeof(EAPPasswordBox), new PropertyMetadata(OnShowTextPropertyChanged));
public EAPPasswordBox()
{
InitializeComponent();
this.ShowText = false;
}
private static void OnShowTextPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
EAPPasswordBox passwordBox = d as EAPPasswordBox;
if (passwordBox != null)
{
passwordBox.ShowText=(bool)e.NewValue;
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
private void _root_Loaded(object sender, RoutedEventArgs e)
{
this.pwdBox.SetBinding(PasswordBox.PasswordProperty, new System.Windows.Data.Binding() { Source = this.DataContext, Path = new PropertyPath(PasswordPropertyName), Mode = BindingMode.TwoWay, ValidatesOnDataErrors = true });
this.txtBox.SetBinding(TextBox.TextProperty, new System.Windows.Data.Binding() { Source = this.DataContext, Path = new PropertyPath(PasswordPropertyName), Mode = BindingMode.TwoWay, ValidatesOnDataErrors = true });
}
}
Here's the XAML of the control.
<UserControl x:Class="GAB.EAP2011.Controls.EAPPasswordBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400" x:Name="_root" Loaded="_root_Loaded">
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Top">
<PasswordBox x:Name="pwdBox" />
<TextBox x:Name="txtBox" />
</StackPanel>
</Grid>
Here's how to use it:
<local:EAPPasswordBox x:Name="pwdBox"
Grid.Column="1" Grid.Row="0" Grid.ColumnSpan="2" PasswordPropertyName="password" ShowText="{Binding showPassword,Mode=TwoWay}"></local:EAPPasswordBox>
Now you got a nice password visibility switcher control :)
Comments appreciated!