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WPF. Button.IsDefault = true. Without UpdateSourceTrigger=PropertyChanged

I have many forms with a lot of textboxes. And I want to add to that forms a button with IsDefault = true. Then fill any property and press enter. If I will not set UpdateSourceTrigger=PropertyChanged on textbox, it will not see my input.
The problem is that I do not want to add UpdateSourceTrigger=PropertyChanged to each textbox, combobox, checkbox, and etc.
Is there any way to trigger everything to write it's data to the source without adding UpdateSourceTrigger=PropertyChanged?

Call the BindingExpression.UpdateSource method in the click event handler for each of the Controls (TextBox, CheckBox, etc.) that you have in your Window/UserControl, like this:
private void ButtonBase_OnClick(object sender, RoutedEventArgs e) {
this.UpdateSourceTrigger(this);
MessageBox.Show($"Field1: {this.vm.Field1}\nField2: {this.vm.Field2}\nField3: {this.vm.Field3}");
}
public void UpdateSourceTrigger(UIElement element) {
if (element == null) return;
var children = LogicalTreeHelper.GetChildren(element);
foreach (var e in children) {
if (e is TextBox txtBox) {
var binding = txtBox.GetBindingExpression(TextBox.TextProperty);
binding?.UpdateSource();
}
if (e is CheckBox chkBox) {
var binding = chkBox.GetBindingExpression(CheckBox.IsCheckedProperty);
binding?.UpdateSource();
}
// add other types, like ComboBox or others...
// ...
this.UpdateSourceTrigger(e as UIElement);
}
}

user control loses keyboard focus

I made a user control, which I called InputTextBox, that present text which the user can edit only after clicking the control:
<Grid>
<TextBox Name="box"
Text="{Binding RelativeSource={RelativeSource AncestorType=local:InputTextBlock}, Path=Text, Mode=TwoWay}"
Visibility="Hidden"
LostKeyboardFocus="box_LostKeyboardFocus"
KeyDown="box_KeyDown"/>
<Button Name="block"
Background="Transparent"
BorderThickness="0"
Click="block_Click">
<Button.Content>
<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType=local:InputTextBlock}, Path=Text}" />
</Button.Content>
</Button>
</Grid>
When the user click the button the following callack is used:
private void block_Click(object sender, RoutedEventArgs e)
{
StartEdit();
}
public void StartEdit()
{
box.Visibility = Visibility.Visible;
block.Visibility = Visibility.Hidden;
box.CaretIndex = box.Text.Length;
Keyboard.Focus(box);
}
There are two more important events that are handled within the control. The first is when the control loses keyboard focus:
private void box_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
box.Visibility = Visibility.Hidden;
block.Visibility = Visibility.Visible;
}
And the other is when the user presses the TAB or ENTER keys:
private void box_KeyDown(object sender, KeyEventArgs e)
{
Key key = e.Key;
if (key == Key.Enter || key == Key.Tab)
{
RoutedEventArgs args = new RoutedEventArgs(KeyExitEvent, this, e.Key);
RaiseEvent(args);
}
}
This raises a simple routed event I registered for this control called KeyExit.
So, basically, it's like this control has two "modes": "edit mode" which the user can activate by simply clicking on the control, and "view mode", which the user can return to by giving any other control in the UI keyboard focus.
In my UI I have a stack panel with a bunch of these controls in it - each one is wrapped inside a class I created that is similar in concept to ListViewItem. The idea is that when the user is in edit mode inside one of the items in the stack panel and click the TAB or ENTER key, the next control in the panel will get into edit mode.
So, I have the following event callback:
private void item_KeyExit(object sender, RoutedEventArgs e)
{
FrameworkElement obj = e.OriginalSource as FrameworkElement;
if (obj != null)
{
var listItem = VisualTreeHelperUtils.FindFirstAncestorOfType<MyListItem>(obj);
if (listItem != null)
{
int itemIndex = stackPanelList.Children.IndexOf(listItem);
MyListItem nextItem = null;
if (itemIndex == ucSortableList.Children.Count - 1)
{
nextItem = stackPanelList.Children[itemIndex+1] as MyListItem;
}
if (nextItem != null)
{
var item = nextItem.DataContent; // property I made in MyListItem that gives access to the class it wraps
InputTextBlock block = item as InputTextBlock;
if (block != null)
{
block.StartEdit();
}
}
}
}
}
Everything is called properly, but immediately after all of it is done, the previous item, which I tabbed out of, gets the keyboard focus back and cause no item in the stack to be in edit mode. So, if, for example, the first item in the stack was in edit mode, once the user hit the tab key, the second item in the stack gets into edit mode, but then the first item gets keyboard focus back immediately. Can anybody understand why this is happening?

StackPanel Focusable is false by default. Suggest ensure it's true.
Also for checking indeces, one generally wants the index to be < count. So your index + 1 could == count if it's == count - 1. Don't you want:
if (itemIndex < ...Count - 1)
That way, item index + 1 will always be <= Count - 1 ?
if (itemIndex == ucSortableList.Children.Count - 1)
{
nextItem = stackPanelList.Children[itemIndex+1] as MyListItem;
}
Also you can use box.Focus() instead of Keyboard.Focus(box) but that may not be necessary.

Update DataGrid's ItemsSource on SelectionChanged event of a ComboBox

I subscribed to a SelectionChangedEvent on a ComboBox in a DataGrid with the following code:
public static DataGridTemplateColumn CreateComboboxColumn(string colName, Binding textBinding, SelectionChangedEventHandler selChangedHandler = null)
{
var cboColumn = new DataGridTemplateColumn {Header = colName};
...
if (selChangedHandler != null)
cboFactory.AddHandler(Selector.SelectionChangedEvent, selChangedHandler);
...
return cboColumn;
}
The handler I actually register contains:
private void ComboBoxSelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
Console.WriteLine(#"selectHandler");
var cboBox = sender as ComboBox;
if (cboBox == null)
return;
if (cboBox.IsDropDownOpen) // a selection in combobox was made
{
CommitEdit();
}
else // trigger the combobox to show its list
cboBox.IsDropDownOpen = true;
}
... and is located in my custom DataGrid class.
If I select an item in the ComboBox, e.AddedItems and cboBox.SelectedItem contains the selected value, but nothing is changed on CommitEdit().
What I want is to force a commit to directly update the DataGrid's ItemsSource, when the user selects an item in the drop-down-list. Normally this is raised if the control looses focus...
The link in the solution found in this thread is not available any more and I don't know how to use this code.

I created a tricky, but working, solution for my problem. Here's the modified handler from above:
private void ComboBoxSelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
Console.WriteLine(#"selectHandler");
var cboBox = sender as ComboBox;
if (cboBox == null)
return;
if (cboBox.IsDropDownOpen) // a selection in combobox was made
{
cboBox.Text = cboBox.SelectedValue as string;
cboBox.MoveFocus(new TraversalRequest(FocusNavigationDirection.Right));
}
else // user wants to open the combobox
cboBox.IsDropDownOpen = true;
}
Because my ComboBoxColumn is a custom DataGridTemplateColumn I force it to show its list, when the user first selects the cell.
To change the bound items value I manually overwrite the displayed text with recently selected item and force the UI to select another item (in this case the control to the right) to make an implicit call to CellEditEnding event, which (in my case) commits the whole row:
private bool _isManualEditCommit = false;
private void _CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{
// commit a manual edit
// this if-clause prevents double execution of the EditEnding event
if (!_isManualEditCommit)
{
Console.WriteLine(#"_CellEditEnding() manualeditcommit");
_isManualEditCommit = true;
CommitEdit(DataGridEditingUnit.Row, true);
_isManualEditCommit = false;
checkRow(e.Row);
}
}
Maybe I could help somebody with this "dirty" solution ;-)

TextBox ScrollToEnd Glitches When Selecting if Text is Appeneded

I'm making a textbox to autoscroll to the end when text is added. However I wanted the option to not scroll the textbox when the mouse is over the textbox. I've done all that, but when the user selects text and the textbox receives an event to update the text, everything goes haywire.
Here's what I'm working with:
<TextBox Text="{Binding ConsoleContents, Mode=OneWay}" TextWrapping="Wrap"
IsReadOnly="True" ScrollViewer.VerticalScrollBarVisibility="Visible"
TextChanged="TextBox_TextChanged" MouseEnter="TextBox_MouseEnterLeave"
MouseLeave="TextBox_MouseEnterLeave" AllowDrop="False" Focusable="True"
IsUndoEnabled="False"></TextBox>
private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
TextBox textBox = sender as TextBox;
if (textBox == null) return;
// ensure we can scroll
if (_canScroll)
{
textBox.Select(textBox.Text.Length, 0); //This was an attempt to fix the issue
textBox.ScrollToEnd();
}
}
private void TextBox_MouseEnterLeave(object sender, MouseEventArgs e)
{
TextBox textBox = sender as TextBox;
// Don't scroll if the mouse is in the box
if (e.RoutedEvent.Name == "MouseEnter")
{
_canScroll = false;
}
else if (e.RoutedEvent.Name == "MouseLeave")
{
_canScroll = true;
}
}
To further explain what haywire means, when the textbox receives and propertychanged event it sets the text and scrolls down to the end if the mouse is not hovering over it. If the mouse is hovering over it does not scroll. But if I select text and the textbox recives the propertychanged event the content gets updated, but the box does not scroll down. This is expected. The problem is that my selection then goes from where the cursor currently is to the top of the text. If I remove the cursor from the box, it continues fine but once the cursor returns, the box gets stuck at the top and cannot scroll down. I thought it might have been the cursor so I try to move it to the end but that solves nothing.
Any ideas?!
I've been ripping my hair out! Thanks!

You will need to handle the extra case of PropertyChanged event. Because the text is changed the control is updated. Because it updates it resets certain values, like cursor location and selected text and such.
You can try to temporarily save these settings like CaretIndex, SelectionStart and SelectionLength. Although I have no experience with this, so you will have to find out for yourself what values you want to keep.
You could also apply the same _canScroll check when the PropertyChanged event is triggered for the TextBox. This allows you to work with the text. But if the mouse leaves the Textbox you must wait for a new event before the latest text is shown.
You might also want to look into using IsFocused property. In my opinion it gives a nicer solution than the MouseEnter and MouseLeave event. But that's up to you of course.

Well it took all morning but here's how to do it:
<TextBox Text="{Binding ConsoleContents, Mode=OneWay}"
TextWrapping="Wrap" IsReadOnly="True" ScrollViewer.VerticalScrollBarVisibility="Visible" TextChanged="TextBox_TextChanged"
MouseEnter="TextBox_MouseEnterLeave" MouseLeave="TextBox_MouseEnterLeave" SelectionChanged="TextBox_SelectionChanged" AllowDrop="False" Focusable="True"
IsUndoEnabled="False"></TextBox>
public partial class ConsoleView : UserControl
{
private bool _canScroll;
// saves
private int _selectionStart;
private int _selectionLength;
private string _selectedText;
public ConsoleView(ConsoleViewModel vm)
{
InitializeComponent();
this.DataContext = vm;
_canScroll = true;
}
private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
TextBox textBox = sender as TextBox;
if (textBox == null) return;
// ensure we can scroll
if (_canScroll)
{
// set the cursor to the end and scroll down
textBox.Select(textBox.Text.Length, 0);
textBox.ScrollToEnd();
// save these so the box doesn't jump around if the user goes back in
_selectionLength = textBox.SelectionLength;
_selectionStart = textBox.SelectionStart;
}
else if (!_canScroll)
{
// move the cursor to where the mouse is if we're not selecting anything (for if we are selecting something the cursor has already moved to where it needs to be)
if (string.IsNullOrEmpty(_selectedText))
//if (textBox.SelectionLength > 0)
{
textBox.CaretIndex = textBox.GetCharacterIndexFromPoint(Mouse.GetPosition(textBox), true);
}
else
{
textBox.Select(_selectionStart, _selectionLength); // restore what was saved
}
}
}
private void TextBox_MouseEnterLeave(object sender, MouseEventArgs e)
{
TextBox textBox = sender as TextBox;
if (textBox == null) return;
// Don't scroll if the mouse is in the box
if (e.RoutedEvent.Name == "MouseEnter")
{
_canScroll = false;
}
else if (e.RoutedEvent.Name == "MouseLeave")
{
_canScroll = true;
}
}
private void TextBox_SelectionChanged(object sender, RoutedEventArgs e)
{
TextBox textBox = sender as TextBox;
if (textBox == null) return;
// save all of the things
_selectionLength = textBox.SelectionLength;
_selectionStart = textBox.SelectionStart;
_selectedText = textBox.SelectedText; // save the selected text because it gets destroyed on text update before the TexChanged event.
}
}

Silverlight Programmatically select text

I am playing with a Silverlight control that has a TextBox and Button. When I click the button (which calls SelectText below), I want to select all the text in the textbox.
Here's my code:
private void SelectText()
{
TextBox tb = this.txtFirstName;
tb.SelectionStart = 0;
tb.SelectionLength = 3;
// tb.Select(0, this.txtFirstName.Text.Trim().Length - 1);
// tb.SelectAll();
// tb.Text = String.Empty;
}
The commented code is what I tried already, but neither is working.
Anyone have suggestions on what I'm doing wrong?

You might need to give focus to the textbox to see the actual selection happening (either before or after selecting, it might not matter but you'll have to try):
private void SelectText()
{
TextBox tb = this.txtFirstName;
tb.SelectionStart = 0;
tb.SelectionLength = 3;
// tb.Select(0, this.txtFirstName.Text.Trim().Length - 1);
// tb.SelectAll();
// tb.Text = String.Empty;
tb.Focus();
}

SelectAll() works -- I've used it more than once. Is something manipulating the text box after this method happens?

This does the trick for the entire User Control.
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
}
protected override void OnGotFocus(RoutedEventArgs e)
{
TextBox tb = e.OriginalSource as TextBox;
if (tb != null)
tb.SelectAll();
base.OnGotFocus(e);
}
}

The focus solution worked for me, but sometimes I get this ExecutionEngineException during the SelectAll() and it's totally bogus! Even a try...catch won't stop it and there's no more details about the error.