I'm trying to write an extension method that will allow me to set focus on a Control. I've written the method below which works fine, however if the control is already loaded then obviously hooking up the Loaded event isn't going to be any use - I also need a way to check if the control has been loaded so I can simply run the Focus() code without hooking up the event.
Is there any way to simulate an IsLoaded property on a control?
public static void SetFocus(this Control control)
{
// return if the control is not visible
if (control.Visibility == Visibility.Collapsed) { return; }
control.Loaded += (sender, routedeventArgs) =>
{
// focus the Silverlight plugin first
System.Windows.Browser.HtmlPage.Plugin.Focus();
control.IsTabStop = true; // required to allow Focus
control.Focus();
if (control is TextBox)
{
((TextBox)control).SelectAll();
}
};
}
EDIT: As per ColinE's answer below, I implemented it like this:
public static void SetFocus(this Control control)
{
// return if the control is not visible
if (control.Visibility == Visibility.Collapsed) { return; }
if (control.Descendants().Count() > 0)
{
// already loaded, just set focus and return
SetFocusDelegate(control);
return;
}
// not loaded, wait for load before setting focus
control.Loaded += (sender, routedeventArgs) =>
{
SetFocusDelegate(control);
};
}
public static void SetFocusDelegate(Control control)
{
// focus the Silverlight plugin first
System.Windows.Browser.HtmlPage.Plugin.Focus();
control.IsTabStop = true; // required to allow Focus
control.Focus();
if (control is TextBox)
{
((TextBox)control).SelectAll();
}
}
If a control has not been loaded, then the various elements within its template will not have been constructed. Using Linq-to-VisualTree you can confirm this:
Debug.WriteLine(control.Descendants().Count());
control.Loaded += (s, e) =>
{
Debug.WriteLine(foo.Descendants().Count());
};
The first debug output should show '0', the second will be a number >0 which indicates the number of child elements of the control once the template has been applied.
or it is enough to check the parent:
var parent = System.Windows.Media.VisualTreeHelper.GetParent(control);
if the parent is null, then the control is not loaded (because it doesn't have a parent in a visual tree)
Related
My winform contains a TextBox that is the main control of the form. When I do CtrL + C, and often end up with an empty clipboard because for some reason the ActiveControl of the form is set to another control, like for instance the TabControl, the SplitContainer, etc. I tried to set those control TabStop = fasle, but to avail. Is there a way to prevent all controls from getting focus ? Not only regarding the mouse clicks, but also the tab keys.
I can imagine trying with some native windows messages like WM_SetFocus, or some native windows styles like WS_TABSTOP, or some control styles like ControlStyles.Selectable, or ControlStyles.UserMouse, but I'd say you cannot find a generic solution which handles all controls.
What I'm proposing here (according to your comments, looking for a better way of handling focus rather than trying to make things focusable, which makes more sense in UX point of view as well) is handling TabControl and SplitterContainer focus related events:
Tab control: Handle SelectedIndexChanged, and then move the focus to the first focusable control of the tab.
Splitter container: Handle MouseDown to trap the start of splitting, then store the active panel; later handle SplitterMoved and move the focus to he first focusable control of the active panel.
Here is what worked for me:
SplitterPanel activePanel;
private void splitContainer1_SplitterMoved(object sender, SplitterEventArgs e)
{
splitContainer1.SelectNextControl(activePanel,
forward: true, tabStopOnly: true, nested: true, wrap: true);
}
private void splitContainer1_MouseDown(object sender, MouseEventArgs e)
{
activePanel = splitContainer1.Panel1.ContainsFocus ? splitContainer1.Panel1 :
splitContainer1.Panel2.ContainsFocus ? splitContainer1.Panel2 : null;
}
private void tabControl1_SelectedIndexChanged(object sender, EventArgs e)
{
var page = this.tabControl1.SelectedTab;
page.SelectNextControl(null,
forward: true, tabStopOnly: true, nested: true, wrap: true);
}
Instead of preventing focus, which might cause problems for those trying to navigate your app using only the keyboard, implement the IMessageFilter interface and trap Ctrl-C for your whole app. Then you can simply put the contents of your "main textbox" on the clipboard manually:
public partial class Form1 : Form, IMessageFilter
{
public Form1()
{
InitializeComponent();
Application.AddMessageFilter(this);
}
bool IMessageFilter.PreFilterMessage(ref Message m)
{
if (m.Msg == 0x0100 &&
(Keys)m.WParam.ToInt32() == Keys.C &&
ModifierKeys == Keys.Control)
{
Console.WriteLine("Ctrl-C Trapped!");
if (textBox1.SelectionLength > 0)
{
Clipboard.SetText(textBox1.SelectedText);
}
else
{
Clipboard.SetText(textBox1.Text);
}
return true;
}
return false;
}
}
I have a Window with seven buttons; I use it as a menu in a simple game I am working on, but I display it as a dialog. How can I know which button user has pressed, since DialogResult in WPF only offers true, false and null?
If you're making a custom Window in this way, you don't really need to worry about DialogResult.
You can keep track of this in a property within your Window, and just read the property after the dialog is closed.
MyDialog window = new MyDialog();
if (window.ShowDialog() == false)
{
// user closed the window...
}
var choice = window.CustomPropertyContainingChoice;
Define your own enum and offer a static method to display the window that return your enum.
The code below does the same thing it is part of a window that allows users to review their changes and accept or cancel. As I only need true and false I used a bool however it would be trivial to change to an enum.
public static bool DisplayChanges(List<INormalizedMessage> LstMessages)
{
var retlist = LstMessages.Where(( INormalizedMessage NM ) => { return NM.Status != NormalizedMessageStatus.NoChange; });
ReviewChanges RC = new ReviewChanges();
RC.Messages = retlist.ToList();
RC.ShowDialog();
return RC.Result;
}
private void cmdCancle_Click( object sender, RoutedEventArgs e )
{
Result = false;
Hide();
}
private void cmdOK_Click( object sender, RoutedEventArgs e )
{
Result = true;
Hide();
}
I've got a small DataForm and I want to set the focus on the first TextBox. I'm using the Novermber 2009 Toolkit. I've named the TextBox and tried using .Focus() from the DataForm's loaded event. I see it get focus for one cursor 'blink' and then it's gone. I'm trying to work out if this is an artefact of the DataForm or something else. Does anyone know if I should be able to do this?
A little trick I've used successfully is to subscribe to the Loaded event of the textbox, then in the event handler, I set the focus with code such as this:
private void TextBox_Loaded(object sender, RoutedEventArgs e)
{
TextBox usernameBox = (TextBox)sender;
Dispatcher.BeginInvoke(() => { usernameBox.Focus(); });
}
I tried loads of suggestions e.g. using Dispatcher, UpdateLayout etc etc. floating around on various internet sites and none of them worked reliably for me. In the end I settled on the following:
private bool _firstTime = true;
private void MyChildWindow_GotFocus(object sender, RoutedEventArgs e)
{
if (_firstTime)
{
try
{
var dataForm = MyDataForm;
var defaultFocus = dataForm.FindNameInContent("Description") as TextBox;
defaultFocus.Focus();
}
catch (Exception)
{
}
finally
{
_firstTime = false;
}
}
}
Not pretty I know...but it works. There appears to be a timing issue with using the Focus() method in SL4.
Try calling my custom focus setting function (FocusEx).
internal static class ControlExt
{
// Extension for Control
internal static bool FocusEx(this Control control)
{
if (control == null)
return false;
bool success = false;
if (control == FocusManager.GetFocusedElement())
success = true;
else
{
// To get Focus() to work properly, call UpdateLayout() immediately before
control.UpdateLayout();
success = control.Focus();
}
ListBox listBox = control as ListBox;
if (listBox != null)
{
if (listBox.SelectedIndex < 0 && listBox.Items.Count > 0)
listBox.SelectedIndex = 0;
}
return success;
}
}
That should work for you.
Jim McCurdy
YinYangMoney
Are there any known issues when databinding to a control's visible property?
The control is always NOT visible regardless of what my property is.
Public ReadOnly Property IsRibbonCategory() As Boolean
Get
Return True
End Get
End Property
I tried the control's text property and other properties and they seem to work correctly.
I am trying to set a Panel's visible property.
I've found that life is better if you assume that binding to a control's Visible property is broken, despite the fact that it sometimes works. See http://support.microsoft.com/kb/327305, which says as much (and while the KB article applies to .NET 1.0 and 1.1, it still seems to be a problem in at least 2.0).
I created a utility class for creating bindings which, among other things, gave me a centralized place to add a work-around. Instead of actually creating a binding on Visible it does two things:
It subscribes to the data source's INotifyPropertyChanged.PropertyChanged event and sets the Visible value as appropriate when the event is raised.
It sets the initial value of Visible according to the current data source value.
This required a little reflection code, but wasn't too bad. It is critical that you don't bind the Visible property and do the work-around or it won't work.
Workaround: Set the Visible property on the BindingComplete event.
I had same issue setting a label's Visible property - always stays false, even though setting the Enabled property works fine.
I just hit this issue in .NET 4.7.1 and Visual Studio 2017. To fix it, I changed the Visible property on my control to be initially set to True, as I had it as False previously.
Things to check:
Be sure you've instantiated the class that has the IsRibbonCategory property
Did you set the datasource of property of the binding source to the instance of the class
The datasource update mode should be on "on validation"
Make sure you didn't set the visible property manually to false on the control
Hope that helps. Can you post more code?
A workaround would be to use a Component to databind to a control's visiblity property instead of directly binding to the control's visibility property.
See below code:
using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApplication2
{
public class ControlVisibilityBinding : Component
{
private static readonly object EventControlChanged = new object();
private static readonly object EventVisibleChanged = new object();
private System.Windows.Forms.Control _control;
private bool _visible = true;
public event EventHandler VisibleChanged
{
add { Events.AddHandler(EventVisibleChanged, value); }
remove { Events.RemoveHandler(EventVisibleChanged, value); }
}
public event EventHandler ControlChanged
{
add { Events.AddHandler(EventControlChanged, value); }
remove { Events.RemoveHandler(EventControlChanged, value); }
}
public ControlVisibilityBinding()
{
}
public ControlVisibilityBinding(IContainer container)
{
container.Add(this);
}
[DefaultValue(null)]
public System.Windows.Forms.Control Control
{
get { return _control; }
set
{
if(_control == value)
{
return;
}
WireControl(_control, false);
_control = value;
if(_control != null)
{
_control.Visible = _visible;
}
WireControl(_control, true);
OnControlChanged(EventArgs.Empty);
OnVisibleChanged(EventArgs.Empty);
}
}
[DefaultValue(true)]
public bool Visible
{
get { return _visible; }
set
{
if(_visible != value)
{
_visible = value;
}
if(Control != null)
{
Control.Visible = _visible;
}
OnVisibleChanged(EventArgs.Empty);
}
}
private void WireControl(Control control, bool subscribe)
{
if(control == null)
{
return;
}
if(subscribe)
{
control.VisibleChanged += Control_VisibleChanged;
}
else
{
control.VisibleChanged -= Control_VisibleChanged;
}
}
private void Control_VisibleChanged(object sender, EventArgs e)
{
OnVisibleChanged(EventArgs.Empty);
}
protected virtual void OnVisibleChanged(EventArgs e)
{
EventHandler subscribers = (EventHandler)Events[EventVisibleChanged];
if(subscribers != null)
{
subscribers(this, e);
}
}
protected virtual void OnControlChanged(EventArgs e)
{
EventHandler subscribers = (EventHandler)Events[EventControlChanged];
if(subscribers != null)
{
subscribers(this, e);
}
}
}
static class Program
{
[STAThread]
static void Main()
{
using(Form form = new Form())
using(FlowLayoutPanel groupBoxLayoutPanel = new FlowLayoutPanel())
using(RadioButton visibleButton = new RadioButton())
using(RadioButton hiddenButton = new RadioButton())
using(GroupBox groupBox = new GroupBox())
using(Label text = new Label())
using(ControlVisibilityBinding visibilityBinding = new ControlVisibilityBinding())
using(TextBox inputTextBox = new TextBox())
{
groupBoxLayoutPanel.Dock = DockStyle.Fill;
groupBoxLayoutPanel.FlowDirection = FlowDirection.LeftToRight;
groupBoxLayoutPanel.AutoSize = true;
groupBoxLayoutPanel.AutoSizeMode = AutoSizeMode.GrowAndShrink;
visibleButton.Text = "Show Label";
visibleButton.AutoSize = true;
hiddenButton.Text = "Hide Label";
hiddenButton.AutoSize = true;
groupBoxLayoutPanel.Controls.Add(visibleButton);
groupBoxLayoutPanel.Controls.Add(hiddenButton);
inputTextBox.Text = "Enter Label Text Here";
inputTextBox.Dock = DockStyle.Top;
groupBox.AutoSize = true;
groupBox.AutoSizeMode = AutoSizeMode.GrowAndShrink;
groupBox.Controls.Add(groupBoxLayoutPanel);
groupBox.Dock = DockStyle.Fill;
text.AutoSize = true;
text.ForeColor = Color.Red;
text.Dock = DockStyle.Bottom;
text.BorderStyle = BorderStyle.FixedSingle;
text.Font = new Font(text.Font.FontFamily, text.Font.Size * 1.25f, FontStyle.Bold | FontStyle.Italic);
text.DataBindings.Add("Text", inputTextBox, "Text", true, DataSourceUpdateMode.Never);
visibilityBinding.Control = text;
visibleButton.DataBindings.Add("Checked", visibilityBinding, "Visible", true, DataSourceUpdateMode.OnPropertyChanged);
Binding binding = hiddenButton.DataBindings.Add("Checked", visibilityBinding, "Visible", true, DataSourceUpdateMode.OnPropertyChanged);
ConvertEventHandler invertConverter = (sender, e) => e.Value = !((bool)e.Value);
binding.Format += invertConverter;
binding.Parse += invertConverter;
form.Controls.Add(inputTextBox);
form.Controls.Add(text);
form.Controls.Add(groupBox);
Application.Run(form);
}
}
}
}
Here is my turn around, it may be stupid but it worked many times.
I put one Panel control in my form, I make it to Fill my form and I put everything in that Panel. All the controls I bind the Visible property see their visibility change according to the objects in my DataGridView.
I have a Silverlight DataGrid of which I need to check if it has Focus. I know there is a method to set Focus and an event for GotFocus but can't see anyhting for checking if it has focus.
Any Ideas ?
AFAIK there is no direct method or property to check if it has focus, but you should be able to use the FocusManager.GetFocusedElement().
If you then define a extension method, you should be able to call MyDataGrid.HasFocus():
public static class ControlExtensions
{
public static bool HasFocus(this Control aControl)
{
return System.Windows.Input.FocusManager.GetFocusedElement() == aControl;
}
}
[edited: I did test it now:]
However there is catch: the call GetFocusedElement() can return the current focused cell within the DataGrid. So in that case the HasFocus will return false.
To be able to check if the DataGrid or one of its cells are focused, we can adapt our extension method like this
public static class ControlExtensions
{
public static bool HasFocus(this Control aControl, bool aCheckChildren)
{
var oFocused = System.Windows.Input.FocusManager.GetFocusedElement() as DependencyObject;
if (!aCheckChildren)
return oFocused == aControl;
while (oFocused != null)
{
if (oFocused == aControl)
return true;
oFocused = System.Windows.Media.VisualTreeHelper.GetParent(oFocused);
}
return false;
}
}
Hope this helps a bit?