If we want to perform
validation in silverlight we have to use INotifyPropertyChanged interface which notifies clients
that a property value has changed.
Create a user class and implement INotifyPropertyChanged interface.
public class User : INotifyPropertyChanged
{
//Delegate.
public event PropertyChangedEventHandler PropertyChanged;
//Username.
private string
userName;
public string
UserName
{
get { return
userName; }
set
{
//Validate the username for 6 chars.
if (value.Length
< 6)
{
throw new
ArgumentException("User
Name should contain atleast 6 chars");
}
userName = value;
RaisePropertyChanged("UserName");
}
}
//Password.
private string
password;
public string
Password
{
get { return
password; }
set
{
//Validate the password for 6 chars.
if (value.Length
< 6)
{
throw new
ArgumentException("Password
should contain atleast 6 chars");
}
password = value;
RaisePropertyChanged("Password");
}
}
//Occurs when a property value changes.
private void
RaisePropertyChanged(string propertyName)
{
if (this.PropertyChanged
!= null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
In Login.xaml page:-
<Grid x:Name="LayoutRoot">
<Grid.RowDefinitions>
<RowDefinition Height="30"></RowDefinition>
<RowDefinition Height="30"></RowDefinition>
<RowDefinition Height="30"></RowDefinition>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="250"></ColumnDefinition>
<ColumnDefinition Width="100"></ColumnDefinition>
</Grid.ColumnDefinitions>
<sdk:Label Height="28" Grid.Column="0" HorizontalAlignment="Left" Name="lblUserName" Content="Enter User
Name:" VerticalAlignment="Top" Width="100"/>
<TextBox Grid.Column="0" HorizontalAlignment="Right" Name="txtUserName" VerticalAlignment="Top" Width="150">
<TextBox.Text>
<!--Binding should
be twoway-->
<Binding Mode="TwoWay" Path="UserName" NotifyOnValidationError="True" ValidatesOnExceptions="True"/>
</TextBox.Text>
</TextBox>
</Grid>
<Grid Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="250"></ColumnDefinition>
<ColumnDefinition Width="100"></ColumnDefinition>
</Grid.ColumnDefinitions>
<sdk:Label Height="28" Grid.Column="0" HorizontalAlignment="Left" Name="lblPassword" Content="Enter
Password:" VerticalAlignment="Top" Width="100"/>
<TextBox Grid.Column="0" HorizontalAlignment="Right" Name="txtPassword" VerticalAlignment="Top" Width="150">
<TextBox.Text>
<!--Binding should
be twoway-->
<Binding Mode="TwoWay" Path="Password" NotifyOnValidationError="True" ValidatesOnExceptions="True"/>
</TextBox.Text>
</TextBox>
</Grid>
<Button Grid.Row="2" Content="Login" Height="23" HorizontalAlignment="Left" Name="btnLogin" VerticalAlignment="Top" Width="75" />
</Grid>
In constructor:-
public partial class Login: UserControl
{
public Login()
{
InitializeComponent();
//User object.
User
objUser = new User();
LayoutRoot.DataContext = objUser;
}
}
Run the appliction without debugging.
Let me know, if you have any feedback. Mail me for source code. Enjoy reading my articles…
sekhartechblog@gmail.com
