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using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Threading;
using Pfz.DataTypes;
namespace Pfz.WpfControls
{
/// <summary>
/// A control for editing values using the right editor for the data-type.
/// </summary>
public class ValueControl:
UserControl,
IValueControl,
IHasDisplayName
{
/// <summary>
/// RoutedEvent invoked when the value of this control changes.
/// </summary>
public static readonly RoutedEvent ValueChangedEvent =
EventManager.RegisterRoutedEvent
(
"ValueChanged",
RoutingStrategy.Direct,
typeof(EventHandler<ValueChangedEventArgs>),
typeof(ValueControl)
);
/// <summary>
/// Event invoked when the change into the value of this control causes
/// an error.
/// </summary>
public static readonly RoutedEvent ValueChangeThrownExceptionEvent =
EventManager.RegisterRoutedEvent
(
"ValueChangeThrownException",
RoutingStrategy.Direct,
typeof(EventHandler<ValueExceptionEventArgs>),
typeof(ValueControl)
);
private IValueControl fInnerValueControl;
private Type fDataType;
/// <summary>
/// Gets or sets the DataType used by this ValueControl.
/// </summary>
public TypeWrapper DataType
{
get
{
return fDataType;
}
set
{
fDataType = value;
p_MustRecreate();
}
}
private string fDisplayName;
/// <summary>
/// Gets or sets the displayname of the control.
/// </summary>
public string DisplayName
{
get
{
return fDisplayName;
}
set
{
fDisplayName = value;
p_MustRecreate();
}
}
private bool fMustRecreate;
private void p_MustRecreate()
{
if (fMustRecreate)
return;
fMustRecreate = true;
Dispatcher.BeginInvoke(new Action(p_DoRecreate));
}
private void p_DoRecreate()
{
if (!fMustRecreate)
return;
fMustRecreate = false;
var dataType = fDataType;
if (dataType == null)
{
Content = null;
return;
}
var content = ControlFactory.TryCreate(dataType, fDisplayName);
if (content != null)
{
fInnerValueControl = (IValueControl)content;
if (fIsReadOnly)
fInnerValueControl.IsReadOnly = true;
IHasValueChanged hasValueChanged = content as IHasValueChanged;
if (hasValueChanged != null)
hasValueChanged.ValueChanged += p_ValueChanged;
}
else
{
content = new Label { Content = "There is not a registered editor for " + dataType.FullName + "." };
fInnerValueControl = null;
}
Content = content;
}
object fOldValue;
private void p_ValueChanged(object sender, RoutedEventArgs args)
{
p_CheckValueChanged();
}
private void p_CheckValueChanged()
{
object newValue;
try
{
newValue = Value;
}
catch(Exception exception)
{
ValueExceptionEventArgs args = new ValueExceptionEventArgs();
args.Exception = exception;
OnValueChangeThrownException(args);
if (args.Handled)
return;
if (args.Exception == null)
return;
if (args.Exception == exception)
throw;
throw args.Exception;
}
if (object.Equals(fOldValue, newValue))
return;
fOldValue = newValue;
var args2 = new ValueChangedEventArgs();
args2.WasChangedByUserAction = true;
OnValueChanged(args2);
}
/// <summary>
/// Method invoked when the processing os ValueChanged throws an exception.
/// </summary>
protected virtual void OnValueChangeThrownException(ValueExceptionEventArgs args)
{
args.RoutedEvent = ValueChangeThrownExceptionEvent;
RaiseEvent(args);
}
/// <summary>
/// Calls OnValueChanged if needed.
/// </summary>
protected override void OnLostKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnLostKeyboardFocus(e);
p_CheckValueChanged();
}
/// <summary>
/// Invoked when the value changes, be it by user action or code.
/// </summary>
protected virtual void OnValueChanged(ValueChangedEventArgs args)
{
args.RoutedEvent = ValueChangedEvent;
RaiseEvent(args);
}
/// <summary>
/// Event invoked when the value is changed, be it by user action
/// or code.
/// </summary>
public event EventHandler<ValueChangedEventArgs> ValueChanged
{
add
{
AddHandler(ValueChangedEvent, value);
}
remove
{
RemoveHandler(ValueChangedEvent, value);
}
}
/// <summary>
/// Event invoked when the ValueChange process throws an exception.
/// </summary>
public event EventHandler<ValueExceptionEventArgs> ValueChangeThrownException
{
add
{
AddHandler(ValueChangeThrownExceptionEvent, value);
}
remove
{
RemoveHandler(ValueChangeThrownExceptionEvent, value);
}
}
#region IValueContainer Members
/// <summary>
/// Gets or sets the value of the control.
/// </summary>
public object Value
{
get
{
return fInnerValueControl.Value;
}
set
{
if (fMustRecreate)
{
Dispatcher.BeginInvoke(new Action<object>(p_SetValue), DispatcherPriority.DataBind, value);
return;
}
p_SetValue(value);
}
}
private void p_SetValue(object value)
{
var innerControl = fInnerValueControl;
if (innerControl == null)
return;
innerControl.Value = value;
// property is re-read, as between set and new get some difference
// may exist.
fOldValue = Value;
var args = new ValueChangedEventArgs();
OnValueChanged(args);
}
#endregion
#region IValueControl Members
/// <summary>
/// Clears the value of this control.
/// </summary>
public void Clear()
{
if (fMustRecreate)
Dispatcher.BeginInvoke(new Action(Clear), DispatcherPriority.DataBind);
else
if (fInnerValueControl != null)
fInnerValueControl.Clear();
}
private bool fIsReadOnly;
/// <summary>
/// Gets or sets a value indicating if this control is/should be read-only.
/// </summary>
public bool IsReadOnly
{
get
{
return fIsReadOnly;
}
set
{
fIsReadOnly = value;
if (fInnerValueControl != null)
fInnerValueControl.IsReadOnly = value;
}
}
#endregion
}
}
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I started to program computers when I was 11 years old, as a hobbyist, programming in AMOS Basic and Blitz Basic for Amiga.
At 12 I had my first try with assembler, but it was too difficult at the time. Then, in the same year, I learned C and, after learning C, I was finally able to learn assembler (for Motorola 680x0).
Not sure, but probably between 12 and 13, I started to learn C++. I always programmed "in an object oriented way", but using function pointers instead of virtual methods.
At 15 I started to learn Pascal at school and to use Delphi. At 16 I started my first internship (using Delphi). At 18 I started to work professionally using C++ and since then I've developed my programming skills as a professional developer in C++ and C#, generally creating libraries that help other developers do their work easier, faster and with less errors.
Want more info or simply want to contact me?
Take a look at:
http://paulozemek.azurewebsites.net/
Or e-mail me at: paulozemek@outlook.com
Codeproject MVP 2012, 2015 & 2016
Microsoft MVP 2013-2014 (in October 2014 I started working at Microsoft, so I can't be a Microsoft MVP anymore).