I know that the question might seems to easy, but I can't find solution. I have CheckdListBox in my form. I have list of checkboxes inside. If I do that:clbxMyControl.Enabled = false; then I can't scroll to see all items. How to allow scrolling on disabled CheckedListBox?
Thanks!
Instead of disabling the control you should change it's SelectionMode like this:
checkedListBox1.SelectionMode = SelectionMode.None;
The user won't be able to select an item but will be allowed to scroll
You can prevent the user from checking items with the ItemCheck event:
bool listEnabled = true;
private void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e) {
if (!listEnabled) e.NewValue = e.CurrentValue;
}
But do make sure that it is obvious that checking no longer works:
private void setListEnabled(bool enabled) {
listEnabled = enabled;
if (listEnabled) checkedListBox1.BackColor = Color.FromKnownColor(KnownColor.Window);
else checkedListBox1.BackColor = Color.FromKnownColor(KnownColor.Control);
}
The ListBox has only one handle in the Windows API which is set to enabled or disabled. Therefore there is no native way to enable the scrolling but the items.
You might be able to build your own control that has the requested behavior but you will have to paint it your self from scratch which might be a lot of work or you find a third party control that supports the behavior.
Or you can not use the enabled property but change the background/font color to make it look disabled and set:
checkedListBox1.SelectionMode = SelectionMode.None;
Another alternative might be the DataGridView. It is much more powerful, I'm not sure if it disables the scrollbar, too but if it does you are able to make the cells readonly and color them.
You can use this code to make CheckedListBox scrollable.
clbxMyControl.SelectionMode = SelectionMode.None;
Because Enable=false; make control unscrollable because this make the container of checkbox disabled.
Related
I'm trying to implement a slide gesture to open/close the hamburguer menu control, but I'm having trouble closing the menu with version 1.5.1 of the control. With version 1.4.1 I close the menu this way:
var paneGrid = HamburgerMenu.FindDescendantByName("PaneGrid") as Grid;
paneGrid.ManipulationMode = ManipulationModes.TranslateX;
paneGrid.ManipulationCompleted += OnPaneGridManipulationCompleted;
private void OnPaneGridManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e) {
if (e.Cumulative.Translation.X < -50) {
HamburgerMenu.IsPaneOpen = false;
}
}
But with version 1.5.1 the listviews take all space in the control and "OnPaneGridManipulationCompleted" does not get fired... any ideas please?
You can try setting both HorizontalScrollMode and VerticalScrollMode to Disabled on the ListView's inner ScrollViewer to let touch input bypass it.
Since the default value of HorizontalScrollMode is already Disabled. You just need to manually set the VerticalScrollMode as below
if (HamburgerMenuControl.FindDescendantByName("ButtonsListView") is ListView listView)
{
ScrollViewer.SetVerticalScrollMode(listView, ScrollMode.Disabled);
}
The side effect is that you can no longer scroll the ListView vertically. But generally you wouldn't want that(bad design) anyway.
You might also be interested in this answer of mine. :)
I'm working with Xamarin.Forms and I made a CustomRenderer for Checkbox in UWP. When I set all the Checkboxes of my items in the ListView to true by clicking the button "Alle", the Checkboxes are displayed correctly with the check inside the box:
However, if I hover my mouse over the Checkboxes, they immediately change their appearence (the check disappears but it's still selected). In the following screenshot, I moved my cursor over the 3rd - 7th Checkboxes:
This is my overridden OnElementChanged method in the CustomRenderer:
protected override void OnElementChanged(ElementChangedEventArgs<EvaCheckbox> e)
{
base.OnElementChanged(e);
var model = e.NewElement;
if (model == null)
{
return;
}
nativeCheckbox = new CheckBox();
CheckboxPropertyChanged(model, null);
model.PropertyChanged += OnElementPropertyChanged;
nativeCheckbox.Checked += (object sender, Windows.UI.Xaml.RoutedEventArgs eargs) =>
{
model.IsChecked = (bool)nativeCheckbox.IsChecked;
};
nativeCheckbox.Unchecked += (object sender, Windows.UI.Xaml.RoutedEventArgs eargs) =>
{
model.IsChecked = (bool)nativeCheckbox.IsChecked;
};
SetNativeControl(nativeCheckbox);
}
I tried to override the PointerEntered event of nativeCheckbox. It works, for example if I set the model.IsChecked to true on this event, it will be set to true:
nativeCheckbox.PointerEntered += (s, args) =>
{
model.IsChecked = true;
};
But I don't know how to (if even at this place) prevent the checkbox from changing it's appearance when moving the cursor above the Checkbox. Just leaving the triggered event with empty code like this won't change anything about the described behaviour:
nativeCheckbox.PointerEntered += (s, args) => { };
How can I prevent the Checkbox from changing it's appearance when I move my cursor over it?
Update:
I've created a sample project for this issue. You can find the repository here: https://github.com/Zure1/CustomCheckbox
It has the exact same described behavior. In the following screenshot I pressed the button "All" on the bottom of the screen and then the checkboxes look like correct with a check inside of them:
After moving the mouse cursor over the bottom 3 checkboxes, their change their appearance:
Information: I'm debugging on my desktop (Windows 10). I don't know if this issue exists on WinPhone. Just in case you're wondering why my checkboxes are red: My system color in Windows is red.
This is a tricky one as I have been struggling with this issue for a while, I'll try my best to answer this.
TL;DR: It's caused by ViewCell.
The issue comes down to Xamarin Forms ListView and ViewCell.
I haven't been able to track down the cause yet for many months and the way I get around this issue is by refreshing the ListView every time a change happens forcing a redraw of the entire ListView which can really impact performance.
My educated guess on what the cause could be is the rendering code for the ViewCell is missing something.
As for your particular issue, I have created a CheckBoxCell which you can use to display a list of checkboxes with a title. I forked your project and made the changes.
This will display something similar to what you are trying to achieve and doesn't have rendering issues so will be a good starting point. You are able to customize this to display images and the like but you'll have to do that in the platform-specific layout code.
Please note that I have only created the code for UWP and that should be enough to get you going for the other platforms.
I hope this helps somewhat.
I have a ComboBox. It is critical that the user cannot scroll by accident and change the selected value.
How can I prevent the ComboBox from changing the value and text when the use scrolls? Thanks.
Visual Studio 2008
combobox.MouseWheel += new MouseEventHandler(combobox_MouseWheel);
void combobox_MouseWheel(object sender, MouseEventArgs e)
{
((HandledMouseEventArgs)e).Handled = true;
}
If you don't want the user messing with the control, disable it. On another level however, if it's critical the user NOT use the control... maybe you should change the control.
ComboBox.Enabled = false;
I have been asked to write c# winforms app that will give users the ability to select options from a checkbox list and have it automatically redraw/repaint a toolstrip with the selected items.
I am new to winforms so I am not sure how to approach it. Should I be using the BackgroundWorker Process? Invalidate()?
Just alittle confused.
Any assistence of pointing in the right direction would be appreciated.
You probably don't want a BackgroundWorker as that's run on a non-UI thread and would cause problems when you try to modify the toolstrip (you can only work with the UI on the thread the UI was created on). Handle the CheckedChanged events on the checkboxes and then add or remove items from the toolstrip. The repainting should be automatic.
You need to keep tooltips for all options some where (if Tag property of checkboxes is free the put it there). Then when an option is selected or deselected, you need to update tooltips.
Let's suppose you are adding all the checkboxes in a IList. then things will work as follows:
private IList<CheckBox> options= new List<CheckBox>();
private void UpdateTTip()
{
toolTip1.RemoveAll();
foreach (CheckBox c in options)
{
if (c.Checked)
toolTip1.SetToolTip(c, c.Tag.ToString());
}
}
Now you need to call this on checkedchanged event of options check boxes:
private void chk_CheckedChanged(object sender, EventArgs e)
{
UpdateTTip();
}
A toolstrip contains controls by itself - it does not just "paint" buttons you can press. In order to have the toolstrip display different buttons depending on different conditions, you can:
Clear the toolstrip items and re-create the ones that are needed in the current context in code when items are checked in the list you mentioned
Add all the items and design time (with property Visible = false) and only set the necessary ones to Visible = true upon selection in your check listbox
No need to do any painting :-)
I have a dialog with loads of control in it. Each and evey control will be populated during the loading sequence and it might take a while for it to get completely filled. Mean while, I don't wanna allow the user to click on any of the controls. In other words, I wanna disable the control from receiving the events and I don't wanna disable the controls (as it might look odd).Also, I don't wanna subscribe and unsubscribe for the events regular intervals. Is there any way to stop the controls from listening to the events for a brief time ??
Sudarsan Srinivasan
The whole point of disabling controls is to communicate to the user that the control cannot be used at a particular time. This is a convention that users have learned and are used to, so I would advice to follow that. Not doing that may confuse the users.
The easiest way is to disable the container in which the controls are located in, rather than disabling each and every control. A better way (or at least the way that I prefer) is to have a method that will control the Visible and Enabled properties of controls based on which state the UI is in.
The easiest way is to move the control population out of the load event (if possible). Then in Load do something like:
private bool _LoadComplete;
void OnFormLoad(Object sender, EventArgs e)
{
_LoadComplete = true;
InitializeControls();
_LoadComplete = false;
}
void InitializeControls()
{
// Populate Controls
}
void OnSomeControlEvent()
{
if (_LoadComplete)
{
// Handle the event
}
}
Edit A Couple other Ideas:
Set the Application.Cursor = WaitCursor (typically will disallow clicking, but not a 100% guarantee)
Create a "Spinner" control to let the user know that the screen is busy. When loading bring it to the front so it sits on top and covers all other controls. Once you're done loading set it to visible = false and show your other controls
Unfortunately the only way i know of is to have a class variable (called something like _loading) and in each control handler do something like:
If (! _loading )
{
...
}
And in your loading code set _loading = true; once you have finished loading.
If you just want to disable user input, then you can set the form's Enabled property to false.
This has the effect of blocking user input to any of the form's controls, without changing the appearance of the controls; it's the technique used internally by the ShowDialog method.