I have three texboxes and one slider which changes their Text properties. What i have to do is to bind slider's value property with Text textbox property but in a specific way. When one of textboxes are activated(gotfocused) i need slider to change its Text property. And only that one. I have binded it so far but when i move the slider all textboxes are updated.
Any ideas?
I was reading about converters, but i don't see how to implement it within my program.
http://forums.create.msdn.com/forums/t/95548.aspx here you have got code of my slider and textblock.
What about simply changing the active binding when a textbox receives focus:
Code Behind:
private Binding _activeBinding;
private TextBox _activeTextbox;
private TextBox ActiveTextBox
{
get { return _activeTextbox; }
set
{
// Check if a binding exists, initialize if one does not
if (_activeBinding == null)
{
_activeBinding = new Binding("Value");
_activeBinding.Source = this.sld;
}
if (_activeTextbox != null)
{
// Clear the binding
_activeTextbox.ClearValue(TextBox.TextProperty);
}
_activeTextbox = value;
if (_activeTextbox != null)
{
// Set the new binding
_activeTextbox.SetBinding(TextBox.TextProperty, _activeBinding);
}
}
}
private void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
this.ActiveTextBox = sender as TextBox;
}
XAML:
<Grid>
<StackPanel>
<TextBox GotFocus="TextBox_GotFocus">1</TextBox>
<TextBox GotFocus="TextBox_GotFocus">2</TextBox>
<TextBox GotFocus="TextBox_GotFocus">3</TextBox>
<Slider x:Name="sld"></Slider>
</StackPanel>
</Grid>
Related
This is for a Windows 10 Universal App.
XAML:
<RelativePanel Padding="4" Margin="4,12,0,0">
<TextBlock x:Name="Label" Text="Class Name" Margin="12,0,0,4"/>
<ListView x:Name="ClassTextBoxes"
ItemsSource="{Binding TextBoxList}"
SelectionMode="None" RelativePanel.Below="Label">
<ListView.ItemTemplate>
<DataTemplate >
<RelativePanel>
<TextBox x:Name="tbox"
PlaceholderText="{Binding PlaceHolder}"
Text="{Binding BoxText,
Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}"
Padding="4" Width="200" MaxLength="25"/>
<TextBlock x:Name="errorLabel"
RelativePanel.Below="tbox"
Text="{Binding Error, Mode=TwoWay}"
Padding="0,0,0,4"
FontSize="10"
Foreground="Red"/>
<Button Content="Delete" Margin="12,0,0,0" RelativePanel.RightOf="tbox"/>
</RelativePanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</RelativePanel>
Model:
public class TextBoxStrings : BaseModel
{
private string _placeholder;
public string PlaceHolder
{
get { return _placeholder; }
set
{
if (_placeholder != value)
{
_placeholder = value;
NotifyPropertyChanged();
}
}
}
private string _boxText;
public string BoxText
{
get { return _boxText; }
set
{
if (_boxText != value)
{
_boxText = CheckBoxText(value);
NotifyPropertyChanged();
}
}
}
public string CheckBoxText(string val)
{
var r = new Regex("[^a-zA-Z0-9]+");
return r.Replace(val, "");
}
}
ViewModel:
private TrulyObservableCollection<TextBoxStrings> _textBoxList;
public TrulyObservableCollection<TextBoxStrings> TextBoxList
{
get { return _textBoxList; }
set
{
if (_textBoxList != value)
{
_textBoxList = value;
RaisePropertyChanged();
}
}
}
and I add new TextBoxString objects to my TextBoxList collection from within my view-model.
I want to make it that users can't type in certain characters (or rather, they get deleted whenever they
are typed in.
This works...in the model. Setting breakpoints and looking at the values, everything in the Model is working: value goes into the setter and gets changed, _boxText holds the new value that is set from CheckBoxText();
But the problem is, in my View, the textbox doesn't reflect changes to the underlying text that I make in the model.
So if I type in "abc*()" into "tbox", the value in the model will be "abc". The value of the textbox, however, will still be "abc*()".
I have a feeling it has something to do with the fact that I'm editing items that are inside of a collection and I don't have anything implemented to handle changing items within a collection. I was under the impression that using INotifyPropertyChanged and ObservableCollection<T> would take care of that for me.
Does anyone have any suggestions?
Thank you!
Edit: So, now I'm trying to use TrulyObservableCollection because I thought this was the problem, but it hasn't helped. Here it is: https://gist.github.com/itajaja/7507120
But the problem is, in my View, the textbox doesn't reflect changes to the underlying text that I make in the model.
As you've seen, the TextBox do reflect changes to your model. When you type in "abc*()" in the TextBox, the value in the model will be changed to "abc". The problem here is that the binding system in UWP is "intelligent". For TwoWay bindings, changes to the target will automatically propagate to the source and in this scenario, binding system assumes that the PropertyChanged event will fire for corresponding property in source and it ignores these events. So even you have RaisePropertyChanged or NotifyPropertyChanged in you source, the TextBox still won't update.
In WPF, we can call BindingExpression.UpdateTarget Method to force the update. But this method is not available in UWP.
As a workaround, you should be able to use TextBox.TextChanged event to check the input like following:
private void tbox_TextChanged(object sender, TextChangedEventArgs e)
{
var tb = sender as TextBox;
if (tb != null)
{
var originalText = tb.Text;
var r = new Regex("[^a-zA-Z0-9]+");
if (originalText != r.Replace(originalText, ""))
{
var index = (tb.SelectionStart - 1) < 0 ? 0 : (tb.SelectionStart - 1);
tb.Text = r.Replace(originalText, "");
tb.SelectionStart = index;
}
}
}
However it may break your MVVM model, you can use data validation to avoid this and here is a blog: Let’s Code! Handling validation in your Windows Store app (WinRT-XAML) you can refer to. And for my personal opinion, data validation is a better direction for this scenario.
if (_boxText != value)
{
_boxText = CheckBoxText(value);
NotifyPropertyChanged();
}
Try changing this to:
var tmp = CheckBoxText(value);
if (_boxText != tmp)
{
_boxText = tmp;
NotifyPropertyChanged();
}
I hope, in your XAML, the binding to property BoxText is two-way, right?
You should edit BoxText and then send checked value to UI. Just send value to CheckBoxText and already edited should be assigned to _boxText. And then you should send BoxText to UI by calling RaisePropertyChanged("BoxTest"). Please, see the following code snippet:
private string _boxText;
public string BoxText
{
get { return _boxText; }
set
{
if (_boxText != value)
{
_boxText=CheckBoxText(value);
RaisePropertyChanged("BoxText");
}
}
}
There is no difference where you use INotifyPropertyChanged for one property of for properties placed in collection. The complete example with collections and ListView can be seen here
I have a series of textboxes in a usercontrol that do not have accompanying Labels.
I need to provide a means for a user to press Alt+(Some Key) to set focus to each of these textboxes.
If I want to use the built in WPF "AccessText" way of doing this, I would need to put a Label up next to each textbox, specify the content with an '_' character preceding the shortcut key, and specify the "Target" property of each Label to their respective Textbox.
Unfortunately in this case, there are no Labels for each textbox, and there will not be.
Is it possible to specify the AccessText shortcut key for a textbox, without a Label?
you can Handle key combinations press and after that focus on the TextBox :
*.xaml:
<UserControl Loaded="UserControl_Loaded">
<Grid>
<StackPanel>
<TextBox Height="30" x:Name="txt1"/>
<TextBox Height="30" x:Name="txt2"/>
</StackPanel>
</Grid>
</UserControl>
*.cs
public UserControl()
{
InitializeComponent();
}
private void KeyDownEvent(object sender, KeyEventArgs e)
{
bool x = Keyboard.IsKeyDown(Key.System);
if (Keyboard.IsKeyDown(Key.System) && Keyboard.IsKeyDown(Key.B))// Alt+B
{
txt2.Focusable = true;
txt2.Focus();
}
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
var window = Window.GetWindow(this);
window.KeyDown += KeyDownEvent;
txt1.Focusable = true;
txt1.Focus();
}
}
I have created a registration form in silverlight 4, where i have a large number of text-boxes, in front of each text box i have placed a text-block as a required field validator, when any of the textbox left empty while loosing focus, the textblock placed in front of it must become red.
textboxes named textbox1, textbox2 ... and so as the textblocks
the problem is, i do not want code the specific method for each specific textbox, all i want to do is to complete such in just two three methods
here i did some coding which doesn't seems to be correct
private void textBox_LostFocus(object sender, RoutedEventArgs e)
{
var textBox = (TextBox) sender;
if (textbox.Text == "")
{
var textblock = "textblock" + textBox.Name.Remove(0,7);
TextblockColorChange(textblock);
}
}
private void TextblockColorChange(object sender)
{
var textblock = (TextBlock) sender;
textblock.Foreground= new SolidColorBrush(Colors.Red);
}
please suggest some better way to do so..
I'd create a UserControl that contains the TextBlock and the TextBox and use this UserControl everywhere you currently have the TextBlock and TextBox combination. Then this Usercontrol would have the LostFocus logic inside it and update the TextBlock appropriately. This prevents the need to figure out the right name of the control to update.
you need something like this,
XAML part:
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel Orientation="Horizontal" Height="25">
<TextBox Width="150" LostFocus="TextBox_LostFocus"/>
<TextBlock Text="*" Foreground="#FF0000" VerticalAlignment="Center" Margin="10,0,0,0" Visibility="Collapsed"/>
</StackPanel>
</Grid>
C# Part:
private void TextBox_LostFocus(object sender, RoutedEventArgs e)
{
var textbox = sender as TextBox;
if(textbox == null) return;
var stackPanel = textbox.Parent as StackPanel;
if(stackPanel == null) return;
var textBlock = stackPanel.Children.Where(a => a is TextBlock).FirstOrDefault();
if (textBlock == null) return;
if (string.IsNullOrEmpty(textbox.Text)) textBlock.Visibility = Visibility.Visible;
else textBlock.Visibility = Visibility.Collapsed;
}
Whilst I actually prefer Bills approach (although I'd be inclined to use a Templated Control) here is another alternative which is quite fun. In your xaml use this sort of markup:-
<TextBlock Text="Enter Value 1" Foreground="{Binding Tag, ElementName=textBox1, TargetNullValue=Black}" />
<TextBox x:Name="textBox1" LostFocus="txt_LostFocus" />
Your common txt_LostFocus can look like this:-
private void txt_LostFocus(object sender, RoutedEventArgs e)
{
TextBox txt = ((TextBox)sender);
if (String.IsNullOrEmpty(txt.Text))
{
txt.Tag = new SolidColorBrush(Colors.Red);
}
else
{
txt.Tag = null;
}
}
var textblock = "textblock" + textBox.Name.Remove(0,7);
TextblockColorChange(textblock);
This code above will just send a string to TextblockColorChange()
You don't show any other code, but I'm guessing you want to do a FindControl or FindControl like search on that string before passing the result to your code.
I have a simple XAML file, it contains a Label whose Foreground property contains a binding:
<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Width="200" Height="100" >
<Label Content="Sampletext" Foreground="{Binding Path=Color}" />
</Grid>
When I load the template and apply a DataContext the Foreground still has the default value.
Is it possible to get bound foreground value without rendering the Grid?
// Load template
string templatePath = "/WpfApplication1;component/Template.xaml";
Grid grid = Application.LoadComponent(new Uri(templatePath, UriKind.Relative)) as Grid;
// Set dataContext
grid.DataContext = new { Color = Brushes.Green };
// Foregound still has default value
var foreground = ((Label)grid.Children[0]).Foreground;
Project can be downloaded here: http://dl.dropbox.com/u/21096596/WpfApplication1.zip
try
lblName.GetBindingExpression(Label.ForegroundProperty).UpdateTarget();
before
var foreground = ((Label)grid.Children[0]).Foreground;
There are automatic DataContext change notifications, the binding will update if the necessary conditions are met. One of them is that the control is loaded (IsLoaded == true) which is not the case in your code. The control will only load if you add it to the your UI somewhere.
Example test code:
private void Button_Click(object sender, RoutedEventArgs e)
{
Grid grid = null;
Action action = () =>
{
var foreground = ((Label)grid.Children[0]).Foreground;
MessageBox.Show(foreground.ToString());
grid.DataContext = new { Color = Brushes.Green };
foreground = ((Label)grid.Children[0]).Foreground;
MessageBox.Show(foreground.ToString());
};
grid = Application.LoadComponent(new Uri("Stuff/GridOne.xaml", UriKind.Relative)) as Grid;
if (grid.IsLoaded)
{
action();
}
else
{
grid.Loaded += (s, _) => action();
}
// This adds the grid to some StackPanel, if you do not do something like this
// nothing will happen since the control will not be loaded and thus the event
// will not fire, etc.
ControlStack.Children.Add(grid);
}
Why do you need the onetime binding? remove that, and it should work.
Wrap your DataContext in an object, and implement INotifyPropertyChanged, then the binding will update when the property changes, and there's no need to update the binding manually:
public class MyDataContext : INotifyPropertyChanged
{
private Brush color;
public Brush Color
{
get { return color; }
set
{
color = value;
RaisePropertyChanged("Color");
}
}
//implementation of PropertyChanged and RaisePropertyChanged omitted
}
and then update it like so:
var dc = new MyDataContext();
grid.DataContext = dc;
dc.Color = Brushes.Green; //this will trigger the NotifyPropertyChanged and update the binding
//color should be changed now
var foreground = ((Label)grid.Children[0]).Foreground;
Hopefully this helps...
If you want a property of a control to be binding to a property of DataContext but want to change the datacontext in runtime, there is a much more simple way to do it.
Create a ContentControl, then use ContentControl.ContentTemplate
<ContentControl Content=something>
<ContentControl.ContentTemplate>
<DataTemplate>
<Label Foreground="{Binding Path=Color}" />
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
Change the Content of the ContentControl instead of changing DataContext of the Label.
I have a list box displaying the names of help topics which can be added to and the names of the topics changed. Originally it was just displaying strings, but to get the inline editing working I changed it to use a custom type consisting of a string and an InEdit property so the UI can determine whether to display the TextBlock or TextBox:
XAML:
<ListBox ItemsSource="{Binding HelpTopics, Mode=TwoWay}"
SelectedValuePath="Description"
SelectedValue="{Binding SelectedPageId, Mode=TwoWay}"
SelectionChanged="ListBox_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<TextBlock Text="{Binding Description, Mode=TwoWay}"
VerticalAlignment="Center"
MouseLeftButtonUp="TopicTextBlock_MouseLeftButtonUp"
Visibility="{Binding InEdit, Converter={StaticResource boolToVisibilityConverter}, ConverterParameter=contra}"/>
<TextBox Text="{Binding Description, Mode=TwoWay}"
Visibility="{Binding InEdit, Converter={StaticResource boolToVisibilityConverter}, ConverterParameter=pro}"
LostFocus="EditTopicTextBox_LostFocus"
HorizontalAlignment="Stretch" VerticalAlignment="Center"/>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button Margin="5" Content="Add Topic" Command="{Binding AddTopicCommand}"/>
HelpTopics is an ObservableCollection<EditableHelpTopic>.
SelectedPageId is a string.
boolToVisibilityConverter is a converter that does what it says.
What works:
Adding a topic creates a new item and adds it to the list and put the item in to edit mode.
Double clicking on an existing item puts that item into edit mode sets the focus to the TextBox and selects all the text so it can be overwritten.
When the TextBox loses focus the edit is saved and the display returns to the TextBlock.
What doesn't work:
When a new topic is added the TextBox should have focus and the text selected so the user can enter a new name.
So my question is is there a point in the code or an event where I know that the TextBox has been created and is visible so I can set focus and select its contents. I've tried hooking into the SelectionChanged event but when that fires the TextBox hasn't yet been displayed. I also added an event to the OnAddTopicExecute method in the view model which I handled in the view, but again that fired before the TextBox was visible.
Below is the code that supports the above XAML. I've tried to cut it down, but there still seems to be a lot of it, so you can skip this if you're not interested ;)
Code behind:
private DateTime lastClickTime = DateTime.MinValue;
private Point lastClickPosition;
private void TopicTextBlock_MouseLeftButtonUp(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
UIElement element = sender as UIElement;
if ((DateTime.Now - this.lastClickTime).TotalMilliseconds > 300)
{
this.lastClickPosition = e.GetPosition(element);
this.lastClickTime = DateTime.Now;
}
else
{
Point position = e.GetPosition(element);
if (Math.Abs(this.lastClickPosition.X - position.X) < 4 && Math.Abs(this.lastClickPosition.Y - position.Y) < 4)
{
var textBlock = sender as TextBlock;
var editableHelpTopic = textBlock.DataContext as EditableHelpTopic;
editableHelpTopic.InEdit = true;
var parent = textBlock.Parent as Grid;
TextBox textBox = parent.Children.First(c => c.GetType() == typeof(TextBox)) as TextBox;
textBox.Focus();
textBox.SelectAll();
}
}
}
private void EditTopicTextBox_LostFocus(object sender, RoutedEventArgs e)
{
var textBox = sender as TextBox;
var editableHelpTopic = textBox.DataContext as EditableHelpTopic;
editableHelpTopic.InEdit = false;
if (!textBox.Text.Equals(editableHelpTopic.Description))
{
this.editViewModel.RenameTopic(textBox.Text);
}
}
View Model:
public EditViewModel()
{
...
this.AddTopicCommand = new DelegateCommand(this.OnAddTopicExecute, this.OnAddTopicCanExecute);
...
}
where DelegateCommand is an implemetation of ICommand.
private void OnAddTopicExecute(object parameter)
{
var newTopic = new EditableHelpTopic
{
Description = "NewTopic",
InEdit = true
};
this.HelpTopics.Add(newTopic);
this.SelectedPageId = newTopic.Description;
}
Definitions:
public class EditableHelpTopic : INotifyPropertyChanged
{
public bool InEdit { ... }
public string Description { ... }
}
It turned out to be simpler than I thought.
I just needed to add a Loaded event handler to the TextBox:
private void EditTopicTextBox_Loaded(object sender, RoutedEventArgs e)
{
var textBox = sender as TextBox;
var editableHelpTopic = textBox.DataContext as EditableHelpTopic;
if (editableHelpTopic.InEdit)
{
textBox.Focus();
textBox.SelectAll();
}
}