I have a System.Windows.Controls.TextBox which I would like to behave as follows: When you click it, it is determined dynamically if the TextBox gets focus or not. Here's a toy application which contains a failed attempt at accomplishing this:
<!-- MainWindow.xaml -->
<Window x:Class="Focus.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">
<Grid>
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Label Name="myLabel" Grid.Row="0" Background="Red"></Label>
<TextBox Name="myTextbox" Grid.Row="1" Background="Green"></TextBox>
</Grid>
</Window>
// MainWindow.xaml.cs
using System;
using System.Windows;
using System.Windows.Input;
namespace Focus
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
myTextbox.PreviewGotKeyboardFocus += myTextbox_GotKeyboardFocus;
}
private static readonly Random myRandom = new Random();
private void myTextbox_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
int randomInt = myRandom.Next(0, 2); // 0 or 1
myLabel.Content = randomInt;
if(randomInt==0)
{
// PREVENT FOCUS - INSERT CODE HERE. (The line below is a failed attempt.)
FocusManager.SetFocusedElement(this, myLabel);
}
}
}
}
The following code seems to do the trick:
// PREVENT FOCUS - INSERT CODE HERE.
myLabel.Focusable = true;
myLabel.Focus();
myLabel.Focusable = false;
I also changed this line of code:
myTextbox.PreviewGotKeyboardFocus += myTextbox_GotKeyboardFocus;
into this:
myTextbox.GotFocus += myTextbox_GotKeyboardFocus;
I hope you know that you hooked up to the keyboard focus (TAB key).
void textBox1_GotFocus(object sender, System.EventArgs e)
{
if (!this.checkBox1.Checked)
this.checkBox1.Focus();
else
this.textBox1.Focus();
}
Related
I have situation where I want an overlay control to block UI interactions on a Page for everything that is behind a border. I have tried setting Border.ManipulationMode to False. I have set IsTapEnabled, IsRightTapEnabled, IsDoubleTapEnabled, and IsHitTestVisible to False.
I also tried subscribing to the Tapped and PointerEntered events, and setting the args Handled property to true. After all of this I can still click on Buttons through the border, and invoke their commands. Below are a few screenshots for context:
Page with no overlay
Page now has what should be an overlay that blocks controls behind it
A button capturing PointerOver that shouldn't be
Here is the UserControl xaml that becomes the overaly on the Page:
<UserControl x:Class="PocMvvmToolkitApp.Dialogs.DialogShell"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid x:Name="overlayGrid"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch">
<!--dialogShield is the Border that I want to prevent click through on-->
<Border x:Name="dialogShield"
Background="#AAFFFFFF"
IsHitTestVisible="False"
ManipulationMode="None"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
IsDoubleTapEnabled="False"
IsHoldingEnabled="False"
IsRightTapEnabled="False"
IsTapEnabled="False"/>
<Border x:Name="dialogBorder"
BorderBrush="Black"
BorderThickness="1" />
</Grid>
Attempting to handle the events:
public DialogShell()
{
this.InitializeComponent();
this.allDialogs = new List<ExtendedContentDialog>();
this.visibleDialogs = new List<ExtendedContentDialog>();
////Doesn't work
this.dialogShield.PointerEntered += this.OnModalShieldPointerEntered;
this.dialogShield.Tapped += this.OnModalShieldTapped;
}
private void OnModalShieldTapped(object sender, Windows.UI.Xaml.Input.TappedRoutedEventArgs e)
{
////Doesn't block click through
e.Handled = true;
}
private void OnModalShieldPointerEntered(object sender, Windows.UI.Xaml.Input.PointerRoutedEventArgs e)
{
e.Handled = true;
}
On the Page.xaml.cs here is where I add or remove the DialogShell control to the parent Grid on the page:
private void OnDialogStackChanged(Args.DialogStackChangedEventArgs args)
{
switch (args.Context)
{
case Args.DialogStackChangedContext.Showing:
if (this.dialogShell == null)
{
this.dialogShell = new DialogShell();
this.dialogShell.ShowDialog(args.Dialog);
this.rootGrid.Children.Add(this.dialogShell);
Grid.SetColumnSpan(this.dialogShell, 2);
}
break;
case Args.DialogStackChangedContext.Closing:
if (this.dialogShell != null)
{
this.dialogShell.RemoveDialog(args.Dialog);
if (this.dialogShell.AllDialogs.Count == 0)
{
this.rootGrid.Children.Remove(this.dialogShell);
this.dialogShell = null;
}
}
break;
}
}
Any help with this Border situation would be appreciated. Before someone recommends using ContentDialog, please don't, I have my reasons for this setup. Thanks!
I created a new WPF app in Visual Studio and I placed a button using the drag and drop editor but I can't access the button in my .cs file using
MainButton.Content = "Set output to red";
but I get an error
System.NullReferenceException: 'Object reference not set to an instance of an object.'
MainButton was null while running the application.
The drag and drop editor generated this xaml file
<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<Border HorizontalAlignment="Center" VerticalAlignment="Center" BorderBrush="Black" BorderThickness="3">
<TextBlock x:Name="Output" Background="Transparent" TextAlignment="Center" TextWrapping="Wrap" Text="Output" Height="88" Width="264"/>
</Border>
<RadioButton x:Name="Option1" Content="Red Pill" HorizontalAlignment="Left" Margin="135,75,0,0" VerticalAlignment="Top" Checked="RadioButton_Checked" IsChecked="True"/>
<RadioButton x:Name="Option2" Content="Blue Pill" HorizontalAlignment="Left" Margin="536,72,0,0" VerticalAlignment="Top" Checked="RadioButton_Checked_1"/>
<Button x:Name="MainButton" Content="Set output to red" HorizontalAlignment="Left" Margin="279,100,0,0" VerticalAlignment="Top" Width="213" Height="41" Click="MainButton_Click"/>
</Grid>
</Window>
Here's the .cs file
using System.Windows;
using System.Windows.Media;
namespace WpfApp1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void MainButton_Click(object sender, RoutedEventArgs e)
{
if ((bool)Option1.IsChecked)
{
Output.Background = Brushes.Crimson;
}
else
{
Option2.IsChecked = true;
Output.Background = Brushes.DodgerBlue;
}
}
private void RadioButton_Checked(object sender, RoutedEventArgs e)
{
MainButton.Content = "Set output to red";
}
private void RadioButton_Checked_1(object sender, RoutedEventArgs e)
{
MainButton.Content = "Set output to blue";
}
}
}
I can access other things in the UI just fine like radio buttons and text blocks but not the button. Why could this be happening?
During the initialization phase, some variables are going to be null since it hasn't been reached in the call order. RadioButton_Checked is called through event before the button is constructed since it contains the Checked property.
A quick and easy fix is as follows: Check for null in your event calls.
private void RadioButton_Checked (object sender, RoutedEventArgs e)
{
if(MainButton != null)
MainButton.Content = "Set output to red";
}
private void RadioButton_Checked_1 (object sender, RoutedEventArgs e)
{
if (MainButton != null)
MainButton.Content = "Set output to blue";
}
Of course, there are better ways to handle this. You could set checked on a separate event, Initialized, which will handle it much cleaner.
I have an array of combo boxes, and once each combo box is populated with items, I want the first item to be selected automatically. SO I do this:
all_transition_boxes[slide_item].SelectedItem = all_transition_boxes[slide_item].Items[0];
but then later I can not change the index anymore if I want to select some other item. It seems that the index is permanently set to zero. I tried to use SelectedItem instead of SelectedIndex but it doesn't work at all. I would appreciate any help.
//populate each combobox with corresponding elements
for (int i = 0; i < slide_transitions.Count; i++)
{
all_transition_boxes[slide_item].Items.Add("Transition " + (i + 1));
}
all_transition_boxes[slide_item].SelectedItem = all_transition_boxes[slide_item].Items[0];
I have created a sample code to replicate your issue, please check it.
A form with a combobox and two buttons:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525" Activated="Window_Activated">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="329*"/>
<ColumnDefinition Width="34*"/>
<ColumnDefinition Width="154*"/>
</Grid.ColumnDefinitions>
<ComboBox x:Name="comboBox" HorizontalAlignment="Left" Margin="146,78,0,0" VerticalAlignment="Top" Width="120"/>
<Button x:Name="button" Content="Button" HorizontalAlignment="Left" Margin="101,185,0,0" VerticalAlignment="Top" Width="75" Click="button_Click"/>
<Button x:Name="button1" Content="Button" HorizontalAlignment="Left" Margin="266,185,0,0" VerticalAlignment="Top" Width="75" Grid.ColumnSpan="2" Click="button1_Click"/>
</Grid>
</Window>
And the form´s code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Window_Activated(object sender, EventArgs e)
{
var items = new List<string>();
for (var i = 0; i < 10; i++)
{
items.Add("Item" + i);
}
comboBox.ItemsSource = items;
comboBox.SelectedItem = "Item0";
}
private void button_Click(object sender, RoutedEventArgs e)
{
comboBox.SelectedItem = "Item5";
}
private void button1_Click(object sender, RoutedEventArgs e)
{
comboBox.SelectedItem = "Item9";
}
}
}
On your ComboBox (in XAML) set:
SelectedIndex = "0"
You can set it as a setter in a style that is applied to all instances of ComboBox in your array.
I am trying to build a chat application, I would like to mimic facebook tag friends functionality. When the user types # in the textblock, I want to pop a context menu with a list of items. How can this be triggered in wpf mvvm app?
Example.
I would do it the following way :
Subscribe to the TextChanged event and whenever there is a change that contains # then show the popup, otherwise hide it.
Note that it tracks for new changes in the TextBox, therefore the popup will disappear as soon as the user presses another key or in your case when the user selected a user from the auto-completion you have provided in the pop-up.
User hasn't typed #
User just typed #
<Window x:Class="WpfApplication11.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">
<Grid>
<Popup x:Name="MyPopup" Placement="Center">
<Popup.Child>
<Border BorderBrush="Red" BorderThickness="1" Background="White">
<Grid>
<TextBlock>My popup</TextBlock>
</Grid>
</Border>
</Popup.Child>
</Popup>
<TextBox TextChanged="TextBoxBase_OnTextChanged" />
</Grid>
</Window>
Code behind:
using System.Windows;
using System.Windows.Controls;
namespace WpfApplication11
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void TextBoxBase_OnTextChanged(object sender, TextChangedEventArgs e)
{
var textBox = (TextBox) sender;
foreach (TextChange textChange in e.Changes)
{
string substring = textBox.Text.Substring(textChange.Offset, textChange.AddedLength);
if (substring == "#")
{
MyPopup.IsOpen = true;
}
else
{
MyPopup.IsOpen = false;
}
}
}
}
}
That said, you might want to further enhance it and integrate it properly your application ;-)
This question already has answers here:
Command for WPF TextBox that fires up when we hit Enter Key
(5 answers)
Closed 9 years ago.
I have a simple requirment in C# WPF. I got a textbox in which I will enter some text. When I press Enter, I want an event to be fired. My code is
private void AddKeyword(object sender, KeyEventArgs e)
{
if(e.Key == Key.Enter)
{
//DO something
}
}
I have set my Textbox AcceptReturn =True; The Method is simply not working and I dont see any event fired when I press Enter. Please Help me out. Thanks in Advance
This work fine for me
<Window x:Class="WpfApplication1.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">
<Grid>
<TextBox Height="23" HorizontalAlignment="Left" Margin="10,10,0,0" Name="textBox1" VerticalAlignment="Top" Width="190" KeyUp="textBox1_KeyUp" />
</Grid>
</Window>
and
using System.Windows;
using System.Windows.Input;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
e.Handled = true;
MessageBox.Show("Enter Fired!");
}
}
}
}