WPF : Passing Custom data to between Custom Control and parent - wpf

Question

I am total newbie to WPF. I am creating my custom user control which will display the employee data structure which is as follows I have implemented INotifyPropertyChanged also:
Here's code snippet
public class Employee : INotifyPropertyChanged
{
private int id;
private string name;
private double salary;
private EmployeeDesignation designation;
public int ID
{
get
{
return id;
}
set
{
id = value;
OnPropertyChanged(new PropertyChangedEventArgs("ID"));
//PropertyChanged(ID, new PropertyChangedEventArgs("ID"));
}
}
...
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(PropertyChangedEventArgs e)
{
if (PropertyChanged != null)
{
PropertyChanged(this, e);
}
}
}
}
And user control code is as follows :
<UserControl x:Class="Assignment5.EmployeeUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://scenter code herehemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d" DataContext="{Binding RelativeSource={RelativeSource Self}, Path=.}"
d:DesignHeight="196" d:DesignWidth="300">
<Grid Height="182">
<Label Content="Name" Height="28" HorizontalAlignment="Left" Margin="26,57,0,0" Name="label1" VerticalAlignment="Top" Width="76" />
<Label Content="Salary" Height="28" HorizontalAlignment="Left" Margin="26,91,0,0" Name="label2" VerticalAlignment="Top" />
<Label Content="ID" Height="28" HorizontalAlignment="Left" Margin="26,23,0,0" Name="label3" VerticalAlignment="Top" />
<Label Content="Designation" Height="28" HorizontalAlignment="Left" Margin="26,125,0,0" Name="label4" VerticalAlignment="Top" />
<TextBox Text="{Binding ElementName=Employee, Path=ID}" Height="23" HorizontalAlignment="Left" Margin="134,28,0,0" Name="IdTextBox" VerticalAlignment="Top" Width="120" />
<TextBox Text="{Binding ElementName=Employee, Path=Name}" Height="23" HorizontalAlignment="Left" Margin="134,59,0,0" Name="NameTextBox" VerticalAlignment="Top" Width="120" />
<TextBox Text="{Binding ElementName=Employee, Path=Salary}" Height="23" HorizontalAlignment="Left" Margin="134,91,0,0" Name="SalaryTextBox" VerticalAlignment="Top" Width="120" LostFocus="SalaryTextBoxLostFocus" />
<TextBox Text="{Binding ElementName=Employee, Path=designation}" Height="23" HorizontalAlignment="Left" Margin="134,125,0,0" Name="DesignationTextBox" VerticalAlignment="Top" Width="120" />
</Grid>
</UserControl>
Here's code behind file
namespace Assignment5
{
public partial class EmployeeUserControl : UserControl, INotifyPropertyChanged
{
public static readonly DependencyProperty EmpDependancyProperty =
DependencyProperty.Register("Employee", typeof(Employee), typeof(EmployeeUserControl)
, new PropertyMetadata(
new PropertyChangedCallback(
EmployeeUserControl.EmployeeDataChanged)));
public Employee Employee
{
get
{
return (Employee)GetValue(EmpDependancyProperty);
}
set
{
SetValue(EmpDependancyProperty, value);
}
}
public EmployeeUserControl()
{
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
private void SalaryTextBoxLostFocus(object sender, RoutedEventArgs e)
{
MessageBox.Show(Employee.Name);
}
private static void EmployeeDataChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
EmployeeUserControl userControl = d as EmployeeUserControl;
userControl.OnPropertyChanged("Employee");
}
}
}
Here's my parent control...
<Window x:Class="Assignment5.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" xmlns:my="clr-namespace:Assignment5"
DataContext="{Binding RelativeSource={RelativeSource Self}, Path=.}">
<Grid>
<my:EmployeeUserControl Employee="{Binding Path=emp, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True}" HorizontalAlignment="Left" Margin="130,56,0,0" x:Name="employeeUserControl1" VerticalAlignment="Top" Width="285" />
</Grid>
</Window>
and a code behind :
namespace Assignment5
{
public partial class MainWindow : Window
{
public static readonly DependencyProperty EmpDependancyProperty =
DependencyProperty.Register("Employee", typeof(Employee), typeof(EmployeeUserControl)
, new PropertyMetadata(
new PropertyChangedCallback(
EmployeeUserControl.EmployeeDataChanged)));
public Employee Employee
{
get
{
return (Employee)GetValue(EmpDependancyProperty);
}
set
{
SetValue(EmpDependancyProperty, value);
}
}
public MainWindow()
{
emp = new Employee(203,"AAA",23232);
InitializeComponent();
}
}
}
When I run this code. I came to know that Employee object in parent control is getting initialized but in the user control it is not getting initialized. What I am doing wrong here?

Answer 1

Two issues
In your UserControl change the Bindings to
<TextBox Text="{Binding Path=Employee.ID}" Height="23" HorizontalAlignment="Left" Margin="134,28,0,0" Name="IdTextBox" VerticalAlignment="Top" Width="120" />
<TextBox Text="{Binding Employee.Name}" Height="23" HorizontalAlignment="Left" Margin="134,59,0,0" Name="NameTextBox" VerticalAlignment="Top" Width="120" />
<TextBox Text="{Binding Employee.Salary}" Height="23" HorizontalAlignment="Left" Margin="134,91,0,0" Name="SalaryTextBox" VerticalAlignment="Top" Width="120" LostFocus="SalaryTextBoxLostFocus" />
<TextBox Text="{Binding Employee.designation}" Height="23" HorizontalAlignment="Left" Margin="134,125,0,0" Name="DesignationTextBox" VerticalAlignment="Top" Width="120" />
In your Window:
<my:EmployeeUserControl Employee="{Binding Employee, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True}" HorizontalAlignment="Left" Margin="130,56,0,0" x:Name="employeeUserControl1" VerticalAlignment="Top" Width="285" />
In your constructor emp = new Employee(203,"AAA",23232); does not make any sense. Instead do this.Employee = new Employee(203,"AAA",23232);