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//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
//---------------------------------------------------------------------------
using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
namespace System.Windows.Controls
{
/// <summary>
/// A column that displays editable text.
/// </summary>
public class DataGridTextColumn : DataGridBoundColumn
{
static DataGridTextColumn()
{
ElementStyleProperty.OverrideMetadata(typeof(DataGridTextColumn), new FrameworkPropertyMetadata(DefaultElementStyle));
EditingElementStyleProperty.OverrideMetadata(typeof(DataGridTextColumn), new FrameworkPropertyMetadata(DefaultEditingElementStyle));
}
#region Styles
/// <summary>
/// The default value of the ElementStyle property.
/// This value can be used as the BasedOn for new styles.
/// </summary>
public static Style DefaultElementStyle
{
get
{
if (_defaultElementStyle == null)
{
Style style = new Style(typeof(TextBlock));
// Use the same margin used on the TextBox to provide space for the caret
style.Setters.Add(new Setter(TextBlock.MarginProperty, new Thickness(2.0, 0.0, 2.0, 0.0)));
style.Seal();
_defaultElementStyle = style;
}
return _defaultElementStyle;
}
}
/// <summary>
/// The default value of the EditingElementStyle property.
/// This value can be used as the BasedOn for new styles.
/// </summary>
public static Style DefaultEditingElementStyle
{
get
{
if (_defaultEditingElementStyle == null)
{
Style style = new Style(typeof(TextBox));
style.Setters.Add(new Setter(TextBox.BorderThicknessProperty, new Thickness(0.0)));
style.Setters.Add(new Setter(TextBox.PaddingProperty, new Thickness(0.0)));
style.Seal();
_defaultEditingElementStyle = style;
}
return _defaultEditingElementStyle;
}
}
#endregion
#region Element Generation
/// <summary>
/// Creates the visual tree for text based cells.
/// </summary>
protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem)
{
TextBlock textBlock = new TextBlock();
SyncProperties(textBlock);
ApplyStyle(/* isEditing = */ false, /* defaultToElementStyle = */ false, textBlock);
ApplyBinding(textBlock, TextBlock.TextProperty);
DataGridHelper.RestoreFlowDirection(textBlock, cell);
return textBlock;
}
/// <summary>
/// Creates the visual tree for text based cells.
/// </summary>
protected override FrameworkElement GenerateEditingElement(DataGridCell cell, object dataItem)
{
TextBox textBox = new TextBox();
SyncProperties(textBox);
ApplyStyle(/* isEditing = */ true, /* defaultToElementStyle = */ false, textBox);
ApplyBinding(textBox, TextBox.TextProperty);
DataGridHelper.RestoreFlowDirection(textBox, cell);
return textBox;
}
private void SyncProperties(FrameworkElement e)
{
DataGridHelper.SyncColumnProperty(this, e, TextElement.FontFamilyProperty, FontFamilyProperty);
DataGridHelper.SyncColumnProperty(this, e, TextElement.FontSizeProperty, FontSizeProperty);
DataGridHelper.SyncColumnProperty(this, e, TextElement.FontStyleProperty, FontStyleProperty);
DataGridHelper.SyncColumnProperty(this, e, TextElement.FontWeightProperty, FontWeightProperty);
DataGridHelper.SyncColumnProperty(this, e, TextElement.ForegroundProperty, ForegroundProperty);
}
protected internal override void RefreshCellContent(FrameworkElement element, string propertyName)
{
DataGridCell cell = element as DataGridCell;
if (cell != null)
{
FrameworkElement textElement = cell.Content as FrameworkElement;
if (textElement != null)
{
switch (propertyName)
{
case "FontFamily":
DataGridHelper.SyncColumnProperty(this, textElement, TextElement.FontFamilyProperty, FontFamilyProperty);
break;
case "FontSize":
DataGridHelper.SyncColumnProperty(this, textElement, TextElement.FontSizeProperty, FontSizeProperty);
break;
case "FontStyle":
DataGridHelper.SyncColumnProperty(this, textElement, TextElement.FontStyleProperty, FontStyleProperty);
break;
case "FontWeight":
DataGridHelper.SyncColumnProperty(this, textElement, TextElement.FontWeightProperty, FontWeightProperty);
break;
case "Foreground":
DataGridHelper.SyncColumnProperty(this, textElement, TextElement.ForegroundProperty, ForegroundProperty);
break;
}
}
}
base.RefreshCellContent(element, propertyName);
}
#endregion
#region Editing
/// <summary>
/// Called when a cell has just switched to edit mode.
/// </summary>
/// <param name="editingElement">A reference to element returned by GenerateEditingElement.</param>
/// <param name="editingEventArgs">The event args of the input event that caused the cell to go into edit mode. May be null.</param>
/// <returns>The unedited value of the cell.</returns>
protected override object PrepareCellForEdit(FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
{
TextBox textBox = editingElement as TextBox;
if (textBox != null)
{
textBox.Focus();
string originalValue = textBox.Text;
TextCompositionEventArgs textArgs = editingEventArgs as TextCompositionEventArgs;
if (textArgs != null)
{
// If text input started the edit, then replace the text with what was typed.
string inputText = ConvertTextForEdit(textArgs.Text);
textBox.Text = inputText;
// Place the caret after the end of the text.
textBox.Select(inputText.Length, 0);
}
else
{
// If a mouse click started the edit, then place the caret under the mouse.
MouseButtonEventArgs mouseArgs = editingEventArgs as MouseButtonEventArgs;
if ((mouseArgs == null) || !PlaceCaretOnTextBox(textBox, Mouse.GetPosition(textBox)))
{
// If the mouse isn't over the textbox or something else started the edit, then select the text.
textBox.SelectAll();
}
}
return originalValue;
}
return null;
}
// convert text the user has typed into the appropriate string to enter into the editable TextBox
string ConvertTextForEdit(string s)
{
// Backspace becomes the empty string
if (s == "\b")
{
s = String.Empty;
}
return s;
}
/// <summary>
/// Called when a cell's value is to be restored to its original value,
/// just before it exits edit mode.
/// </summary>
/// <param name="editingElement">A reference to element returned by GenerateEditingElement.</param>
/// <param name="uneditedValue">The original, unedited value of the cell.</param>
protected override void CancelCellEdit(FrameworkElement editingElement, object uneditedValue)
{
DataGridHelper.CacheFlowDirection(editingElement, editingElement != null ? editingElement.Parent as DataGridCell : null);
base.CancelCellEdit(editingElement, uneditedValue);
}
/// <summary>
/// Called when a cell's value is to be committed, just before it exits edit mode.
/// </summary>
/// <param name="editingElement">A reference to element returned by GenerateEditingElement.</param>
/// <returns>false if there is a validation error. true otherwise.</returns>
protected override bool CommitCellEdit(FrameworkElement editingElement)
{
DataGridHelper.CacheFlowDirection(editingElement, editingElement != null ? editingElement.Parent as DataGridCell : null);
return base.CommitCellEdit(editingElement);
}
private static bool PlaceCaretOnTextBox(TextBox textBox, Point position)
{
int characterIndex = textBox.GetCharacterIndexFromPoint(position, /* snapToText = */ false);
if (characterIndex >= 0)
{
textBox.Select(characterIndex, 0);
return true;
}
return false;
}
internal override void OnInput(InputEventArgs e)
{
// Text input will start an edit.
// Escape is meant to be for CancelEdit. But DataGrid
// may not handle KeyDown event for Escape if nothing
// is cancelable. Such KeyDown if unhandled by others
// will ultimately get promoted to TextInput and be handled
// here. But BeginEdit on escape could be confusing to the user.
// Hence escape key is special case and BeginEdit is performed if
// there is atleast one non espace key character.
if (DataGridHelper.HasNonEscapeCharacters(e as TextCompositionEventArgs))
{
BeginEdit(e, true);
}
else if (DataGridHelper.IsImeProcessed(e as KeyEventArgs))
{
if (DataGridOwner != null)
{
DataGridCell cell = DataGridOwner.CurrentCellContainer;
if (cell != null && !cell.IsEditing)
{
Debug.Assert(e.RoutedEvent == Keyboard.PreviewKeyDownEvent, "We should only reach here on the PreviewKeyDown event because the TextBox within is expected to handle the preview event and hence trump the successive KeyDown event.");
BeginEdit(e, false);
//
// The TextEditor for the TextBox establishes contact with the IME
// engine lazily at background priority. However in this case we
// want to IME engine to know about the TextBox in earnest before
// PostProcessing this input event. Only then will the IME key be
// recorded in the TextBox. Hence the call to synchronously drain
// the Dispatcher queue.
//
Dispatcher.Invoke((Action)delegate(){}, System.Windows.Threading.DispatcherPriority.Background);
}
}
}
}
#endregion
#region Element Properties
/// <summary>
/// The DependencyProperty for the FontFamily property.
/// Flags: Can be used in style rules
/// Default Value: System Dialog Font
/// </summary>
public static readonly DependencyProperty FontFamilyProperty =
TextElement.FontFamilyProperty.AddOwner(
typeof(DataGridTextColumn),
new FrameworkPropertyMetadata(SystemFonts.MessageFontFamily, FrameworkPropertyMetadataOptions.Inherits, DataGridColumn.NotifyPropertyChangeForRefreshContent));
/// <summary>
/// The font family of the desired font.
/// This will only affect controls whose template uses the property
/// as a parameter. On other controls, the property will do nothing.
/// </summary>
public FontFamily FontFamily
{
get { return (FontFamily)GetValue(FontFamilyProperty); }
set { SetValue(FontFamilyProperty, value); }
}
/// <summary>
/// The DependencyProperty for the FontSize property.
/// Flags: Can be used in style rules
/// Default Value: System Dialog Font Size
/// </summary>
public static readonly DependencyProperty FontSizeProperty =
TextElement.FontSizeProperty.AddOwner(
typeof(DataGridTextColumn),
new FrameworkPropertyMetadata(SystemFonts.MessageFontSize, FrameworkPropertyMetadataOptions.Inherits, DataGridColumn.NotifyPropertyChangeForRefreshContent));
/// <summary>
/// The size of the desired font.
/// This will only affect controls whose template uses the property
/// as a parameter. On other controls, the property will do nothing.
/// </summary>
[TypeConverter(typeof(FontSizeConverter))]
[Localizability(LocalizationCategory.None)]
public double FontSize
{
get { return (double)GetValue(FontSizeProperty); }
set { SetValue(FontSizeProperty, value); }
}
/// <summary>
/// The DependencyProperty for the FontStyle property.
/// Flags: Can be used in style rules
/// Default Value: System Dialog Font Style
/// </summary>
public static readonly DependencyProperty FontStyleProperty =
TextElement.FontStyleProperty.AddOwner(
typeof(DataGridTextColumn),
new FrameworkPropertyMetadata(SystemFonts.MessageFontStyle, FrameworkPropertyMetadataOptions.Inherits, DataGridColumn.NotifyPropertyChangeForRefreshContent));
/// <summary>
/// The style of the desired font.
/// This will only affect controls whose template uses the property
/// as a parameter. On other controls, the property will do nothing.
/// </summary>
public FontStyle FontStyle
{
get { return (FontStyle)GetValue(FontStyleProperty); }
set { SetValue(FontStyleProperty, value); }
}
/// <summary>
/// The DependencyProperty for the FontWeight property.
/// Flags: Can be used in style rules
/// Default Value: System Dialog Font Weight
/// </summary>
public static readonly DependencyProperty FontWeightProperty =
TextElement.FontWeightProperty.AddOwner(
typeof(DataGridTextColumn),
new FrameworkPropertyMetadata(SystemFonts.MessageFontWeight, FrameworkPropertyMetadataOptions.Inherits, DataGridColumn.NotifyPropertyChangeForRefreshContent));
/// <summary>
/// The weight or thickness of the desired font.
/// This will only affect controls whose template uses the property
/// as a parameter. On other controls, the property will do nothing.
/// </summary>
public FontWeight FontWeight
{
get { return (FontWeight)GetValue(FontWeightProperty); }
set { SetValue(FontWeightProperty, value); }
}
/// <summary>
/// The DependencyProperty for the Foreground property.
/// Flags: Can be used in style rules
/// Default Value: System Font Color
/// </summary>
public static readonly DependencyProperty ForegroundProperty =
TextElement.ForegroundProperty.AddOwner(
typeof(DataGridTextColumn),
new FrameworkPropertyMetadata(SystemColors.ControlTextBrush, FrameworkPropertyMetadataOptions.Inherits, DataGridColumn.NotifyPropertyChangeForRefreshContent));
/// <summary>
/// An brush that describes the foreground color.
/// This will only affect controls whose template uses the property
/// as a parameter. On other controls, the property will do nothing.
/// </summary>
public Brush Foreground
{
get { return (Brush)GetValue(ForegroundProperty); }
set { SetValue(ForegroundProperty, value); }
}
#endregion
#region Data
private static Style _defaultElementStyle;
private static Style _defaultEditingElementStyle;
#endregion
}
}
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