How to get actual value and validate of CustomTextbox Text in ViewModel - mvvm

Question

I have created custom component for displaying text with either Simple or Password mode, intention to develop this control is the Silverlight does not support custom TextMode (like Password or Text).
This is my requirement
In addition to the access rights it will be possible for organizations to specify restricted access to certain fields in the database. The access restriction to these fields will be Update and Redacted, thus meaning if a specific field has true against Update then a user will be able to update the field as well as viewing it, and if the field has true against Redacted then the user will only be able to see a redacted value in the filed (possibly asterisks - * * * * *). It will be possible to set a field to being Update-able and Redacted, thus meaning a user will see the redacted view but still be able to go and update the field with a new value. Such a requirement is mostly used when holding sensitive information against a contact or information which could be used to discriminate against the contact.
I have created custom control for this requirement and it is working perfectly. i am able to set TextMode dynamically but i couldn't able to get the original value in my ViewModel. (I am able to get original value in View but can't in ViewModel)
If i am access the original value in View using following then it is work.
string s = UserName.Text;
but not getting this value in ViewModel it is giving me like **.
Following is the complete code for PasswordTextBox control.
namespace QSys.Library.Controls
{
public partial class PasswordTextBox : TextBox
{
#region Variables
private string text = string.Empty;
private string passwordChar = "*";
private int selectionLength = 0;
#endregion
#region Properties
/// <summary>
/// The text associated with the control.
/// </summary>
public new string Text
{
get { return text; }
set
{
text = value;
DisplayMaskedCharacters();
}
}
/// <summary>
/// Indicates the character to display for password input.
/// </summary>
public string PasswordChar
{
get { return passwordChar; }
set { passwordChar = value; }
}
/// <summary>
/// Indicates the input text mode to display for either text or password.
/// </summary>
public Mode TextMode
{
get { return (Mode)GetValue(TextModeProperty); }
set { SetValue(TextModeProperty, value); }
}
public static readonly DependencyProperty TextModeProperty = DependencyProperty.Register("TextMode", typeof(Mode), typeof(PasswordTextBox), new PropertyMetadata(default(Mode)));
#endregion
#region Constructors
public PasswordTextBox()
{
this.Loaded += new RoutedEventHandler(PasswordTextBox_Loaded);
}
#endregion
#region Event Handlers
void PasswordTextBox_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
if (this.TextMode == Mode.Password)
{
text = base.Text;
this.TextChanged += new TextChangedEventHandler(PasswordTextBox_TextChanged);
this.KeyDown += new KeyEventHandler(PasswordTextBox_KeyDown);
this.SelectionChanged += new RoutedEventHandler(PasswordTextBox_SelectionChanged);
DisplayMaskedCharacters();
}
this.Loaded -= PasswordTextBox_Loaded;
}
void PasswordTextBox_SelectionChanged(object sender, RoutedEventArgs e)
{
selectionLength = this.SelectionLength;
}
public void PasswordTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
if (base.Text.Length >= text.Length)
text += base.Text.Substring(text.Length);
else
{
int cursorPosition = this.SelectionStart;
selectionLength = (selectionLength > 1) ? selectionLength : 1;
text = text.Remove(cursorPosition, selectionLength);
}
DisplayMaskedCharacters();
selectionLength = 0;
}
public void PasswordTextBox_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
int cursorPosition = this.SelectionStart;
// Handle Delete and Backspace Keys Appropriately
if (e.Key == System.Windows.Input.Key.Back && cursorPosition > 0)
{
DeleteAt(cursorPosition);
}
else if (e.Key == System.Windows.Input.Key.Delete)
{
DeleteAt(cursorPosition);
}
else
{
if (selectionLength > 0) text = text.Remove(cursorPosition, selectionLength);
base.Text = text;
this.Select((cursorPosition > text.Length ? text.Length : cursorPosition), 0);
DisplayMaskedCharacters();
}
selectionLength = 0;
}
#endregion
#region Private Methods
private void DisplayMaskedCharacters()
{
int cursorPosition = this.SelectionStart;
// This changes the Text property of the base TextBox class to display all Asterisks in the control
base.Text = new string(passwordChar.ToCharArray()[0], text.Length);
this.Select((cursorPosition > text.Length ? text.Length : cursorPosition), 0);
}
private void DeleteAt(int position)
{
if (text.Length > position)
{
text = text.Remove(position, 1);
base.Text = base.Text.Remove(position, 1);
}
}
#endregion
}
}
LoginView.xaml
<control:PasswordTextBox x:Name="UserName" TabIndex="1" Grid.Row="1" TextMode="Password" Text="{Binding Path=LoginModelValue.UserName, Mode=TwoWay,ValidatesOnNotifyDataErrors=True, ValidatesOnExceptions=True, ValidatesOnDataErrors=True, NotifyOnValidationError=True}" HorizontalAlignment="Left" VerticalAlignment="Top" Grid.Column="1" Width="200" Height="25" Validatevalue:UpdateSourceTriggerHelper.UpdateSourceTrigger="True"/>
LoginViewModel.cs
public class LoginViewModel : INotifyPropertyChanged, IRegionMemberLifetime
{
public LoginModel LoginModelValue
{
get { return _LoginModelValue; }
set
{
_LoginModelValue = value;
OnPropertyChanged("LoginModelValue");
}
}
}
LoginModel.cs
namespace QSys.Model
{
public class LoginModel : INotifyPropertyChanged
{
#region Variables
private string _userName;
private string _password;
#endregion
#region Constructor
public LoginModel()
{
}
#endregion
#region Properties
[CustomValidation(typeof(PasswordTextBox), "IsValidUserName")]
[Required(ErrorMessage = "User Name is required")]
[Display(Name = "UserName")]
[StringLength(50)]
//[RegularExpression(#"^[a-zA-Z\\0-9\\.\\,\\'\s]+$", ErrorMessage = "Please enter right format.")]
public string UserName
{
get { return _userName; }
set
{
_userName = value;
OnPropertyChanged("UserName");
ValidateProperty("UserName", value);
}
}
[Required(ErrorMessage = "Password is required")]
[Display(Name = "Password")]
[StringLength(10)]
public string Password
{
get { return _password; }
set
{
_password = value;
OnPropertyChanged("Password");
ValidateProperty("Password", value);
}
}
#endregion
#region INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged = delegate { };
private void OnPropertyChanged(string propertyName)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
#region Private Methods
public bool IsValidObject()
{
ICollection<ValidationResult> results = new Collection<ValidationResult>();
return Validator.TryValidateObject(this, new ValidationContext(this, null, null), results, true) && results.Count == 0;
}
public void ValidateProperty(string propertyName, object value)
{
Validator.ValidateProperty(value, new ValidationContext(this, null, null) { MemberName = propertyName });
}
#endregion
}
}
**I am looking for solution since two days without any luck.
Please help me if you have any solution, your comments or suggestion would be highly appreciated.**
Thanks
Imdadhusen

Answer 1

Wouldn't it be easier to build your own UserControl around the regular TextBox and PasswordBox and just switching their visibility when your dependency property TextMode changes? You could then have a single VM for the UserControl with property Value and bind in TwoWay mode both the TextProperty of the TextBox and the Password property of the PasswordBox to it.

Answer 2

I have resolved using following code.
I am missing Mode=TwoWay in LoginView.xaml:
<control:RestrictedBox Type="Text" Value="{Binding Path=UserName,Mode=TwoWay}">
Thanks,
Imdadhusen