I've implemented checkboxes in my Xamarin Forms App using the following article:
https://alexdunn.org/2018/04/10/xamarin-tip-build-your-own-checkbox-in-xamarin-forms/
The only issue I have is that I can't set the size of Android, there is a question in the comments section, however there is no solution. No matter what I do the SizeRequest is always 64x64 - can anyone offer any suggestions or reason why I can't resize?
Did you try to use before the line 91, the code below in order to scale the control:
Control.ScaleX = 0.70;
Control.ScaleY = 0.70;
Maybe I found a possible solution, check the steps below:
Add a BindableProperty called SizeRequest in the custom CheckBox control.
Create a method GetDefaultCheckBoxDrawable to get the default CheckBox drawable.
Change OnElementChanged method to clear and resize the text, set the width/height based on SizeRequest, reset the button drawable and set a new Background drawable with the default checkbox drawable.
AndroidCheckboxRenderer.cs:
private Drawable GetDefaultCheckBoxDrawable(Android.Views.View view)
{
TypedValue value = new TypedValue();
view.Context.Theme.ResolveAttribute(Android.Resource.Attribute.ListChoiceIndicatorMultiple, value, true);
var origImg = view.Context.Resources.GetDrawable(value.ResourceId);
var porterDuffColor = new Android.Graphics.PorterDuffColorFilter(Element.CheckColor.ToAndroid(), Android.Graphics.PorterDuff.Mode.SrcIn);
origImg.SetColorFilter(porterDuffColor);
return origImg;
}
protected override void OnElementChanged(ElementChangedEventArgs<CustomCheckbox> e)
{
...
// CheckBox displays its height from the TEXT, as well as images.
checkBox.Text = "";
checkBox.SetTextSize(Android.Util.ComplexUnitType.Sp, 0);
// Set the width and height based on SizeRequest
if (Element.SizeRequest >= 0)
{
checkBox.SetWidth((int)Element.SizeRequest);
checkBox.SetHeight((int)Element.SizeRequest);
}
// Reset the Button Drawable
checkBox.SetButtonDrawable(null);
// Set Background Drawable with the default CheckBox
checkBox.SetBackgroundDrawable(GetDefaultCheckBoxDrawable(this));
...
}
Check out my GitHub for the full solution.
I hope this can help you.
Related
So i'am working with tabControl in windows forms application and i want to make the tabs get full width regardless whether the application window is maximized or not.
When the window isn't maximized everything appears great:
But when the window gets maximized the tabs doesn't get the full width:
Is there any known way to fix this problem?
Thanks in advance
You can achieve this in some way by modifying the ItemSize property as described bellow, else you'd have to draw the tab page selectors yourself.
public Form1()
{
InitializeComponent();
tabControl1.SizeMode = TabSizeMode.Fixed;
tabControl1.ItemSize = new Size((tabControl1.Width / tabControl1.TabPages.Count) - 1, tabControl1.ItemSize.Height);
}
//Hook to form or parent container Resize event, either Resize or ResizeEnd.
private void Form1_ResizeEnd(object sender, EventArgs e)
{
tabControl1.ItemSize = new Size((tabControl1.Width / tabControl1.TabPages.Count) - 1, tabControl1.ItemSize.Height);
}
I have a silverlight 4 application which has some text boxes that are as wide as the page.
When there is a validation error, a popup is displayed when the user clicks in the control.
The problem is - it only shows the popup for these long text boxes to the left of the text box. It wont go above or below and so as a consequence, most of the popup is displayed out of the page so its chopped off.
I know that I can re-template the text box and try to adjust the popup myself, but before doing that I just wanted to check to see if someone knew of a simple property or something that I can use to prevent that from happening?
Cheers
Rod.
Good question. I guess I would try to solve this via a somewhat "intelligent" AttachedProperty.
Pseudo code ahead:
<TextBox ... my:PopupUtils.KeepPopupWithinScreen="True"/>
And the (pseudo c#) code:
public static class PopupUtils
{
// remember: pseudo code, just to get the idea
static AttachedProperty KeepPopupWithinScreen = type: bool, default: false,
onChanged: HandleKeepPopupWithinScreenChanged;
private static void HandleKeepPopupWithinScreenChanged(
DependencyObject obj, bool value)
{
obj.Loaded += HandleTargetElementLoaded;
}
private staic void HandleTargetElementLoaded(object sender, ...)
{
var popup = VisualTreeHelper.GetDecendantOfType<Popup>(sender);
if ( popup != null )
{
var offsetController = new OffsetController();
offsetController.SetBinding(ObservedOffsetProperty,
new Binding("HorizontalOffset"){Source=popup});
offsetController.ControlledTarget = popup;
//now to prevent garbageCollection...
SetAttachedOffsetController(popup,offsetController);
}
}
public static AttachedProperty AttachedOffsetController = type:OffsetController;
}
I do this sometimes, so this pattern is actually working quite nicely. Maybe it feels a bit "unnatural" at first.
Just letting you know of the solution I used to this problem.
It was another StackOverflow question which I have lost the reference to so I do apologise for not referencing it properly, but the problem is caused by the Text Box and other control styles having a fixed position of to the side of the control when displaying the validation message.
I simply had to create a copy of the style and have the popup appear at the top of the controls instead of beside it.
Problem Solved.
Cheers
Rod.
I am a wpf newbie. In my wpf app, I have images that load from the web. To avoid gui blocking, I followed the approach as mentioned in How can I keep a WPF Image from blocking if the ImageSource references an unreachable Url?
Works great. Issue is, until the image loads, gui doesn't honor dimensions properties set in the Image node. End result is kind of a 'resize' affect - initially the gui(elements) are of one size and 'readjust' once image is loaded.
I wish to make the load 'smooth'. I want to be able to specify a 'initial default' image. Something like initial image in WPF Image Control
However I am not able to get it to work. May be something like below in ImageAsyncHelper(which is obviously wrong) :
public static readonly DependencyProperty SourceUriProperty = DependencyProperty.RegisterAttached("SourceUri", typeof(Uri), typeof(ImageAsyncHelper), new PropertyMetadata
{
PropertyChangedCallback = (obj,e) =>
{
((Image)obj).SetBinding(Image.SourceProperty,
new Binding("DefaultUri")
{
Source = new Uri("pack://application:,,,/blah/Images/Default.gif", UriKind.RelativeOrAbsolute)
});
}
PropertyChangedCallback += (obj, e) =>
{
((Image)obj).SetBinding(Image.SourceProperty,
new Binding("VerifiedUri")
{
Source = new ImageAsyncHelper { GivenUri = (Uri)e.NewValue },
IsAsync = true,
});
}
});
What are my options?
Try setting the Image elements MinWidth and MaxWidth to the desired size.
I am setting the BackgroundImage of a Windows Form to a 200 x 200 image. The Form is 500 x 500. I want the image to be anchored in the bottom right corner of the form. However the only option available to me is the BackgroundImageLayout property - setting this to 'None' results in the image being anchored to the top left. How can I change this?
Note: I am using .NET 2.0
Just draw it yourself in the OnPaintBackground() method. Add the image to the resources (I called it BkgImage) and make the form code look like this:
public Form1() {
InitializeComponent();
backgroundImage = Properties.Resources.BkgImage;
this.DoubleBuffered = true;
this.SetStyle(ControlStyles.ResizeRedraw, true);
}
private Image backgroundImage;
protected override void OnPaintBackground(PaintEventArgs e) {
base.OnPaintBackground(e);
var rc = new Rectangle(this.ClientSize.Width - backgroundImage.Width,
this.ClientSize.Height - backgroundImage.Height,
backgroundImage.Width, backgroundImage.Height);
e.Graphics.DrawImage(backgroundImage, rc);
}
You cannot do that with the BackgroundImageLayout.
However what you could do is add a PictureBox, anchor it to the bottom right and set it to the lowest z-value. This would result in pretty much the requested effect.
I have a combobox that I have Enabled = false. When that is the case it causes it to shade to a grey. I was wondering if there was a way I could keep the checkbox background color as cornsilk while it is not Enabled?
The situation is that I have a form that I will refresh with data when an item is selected. If the user selects to edit the record I enable the form to accept changes and since it is mainly textboxes I just change the readonly property of those. But the combobox looks different so I want to see what I can do to make it stay the same like the rest of the form...
Any ideas?
I would simply hide it with a TextBox over it and setting its Visible property to false. Then, you your user click the Edit button, you hide your TextBox and show your ComboBox with its Visible property set to true.
Perhaps you wish to update your TextBox.Text property by setting its value to the ComboBox.SelectedItem property value on the SelectedItemChanged() event handler.
Let's suppose the following:
ComboBox cb = new ComboBox();
// Position, size and other properties are set through design.
cb.SelectedIndex = 0; // Forces selection of first item for demo purposes.
TextBox tb = new TextBox();
tb.Size = cb.Size;
tb.Position = cb.Position;
tb.Text = cb.SelectedItem.ToString();
tb.Visible = true;
tb.Readonly = true;
cb.Visible = false;
Then, clicking the Edit button:
private void EditButton_Click(...) {
tb.Visible = false;
cb.Visible = true;
}
And make your TextBox.Text property value follow your SelectedItem:
private void ComboBox_SelectedIndexChanged(...) {
tb.Text = cb.SelectedItem.ToString;
}
And you would only do the reverse of your EditButton_Click() event handler to bring back your form in read-only mode.
You may consider using Jquery UI or other plugins if aesthetics of form are important. You can control entire look and feel with the CSS.
Hiding combobox with textbox is a possibility as suggested by Will but then you will have to use absolute width for the dropdown.