I have a view model that implements IDataErrorInfo that has the validation implementation.
I also have a user control, that contains a label and a textBox.
When I use ValidatesOnDataErrors=True on the Text property of my control, if the Text is not valid the whole control becomes red (even the label).
How can I handle the validation error inside my user control so that only the textBox to become red?
<controls:TextBoxControl Label="Test:"
Text="{Binding PersonalModel.Test, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
And my control implementation has a dependency property:
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(TextBoxControl),
new FrameworkPropertyMetadata(default(string), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
Related
I cannot properly bind to a UserControl property placed in a Page.
I have this UserControl :
<UserControl x:Class="xxxx.NumericBox" (...)>
<TextBox Name="TextBoxValue" Text="{Binding RelativeSource {RelativeSource AncestorType=UserControl}, Path=Value, Mode=TwoWay}" (...)
With this behind code :
public partial class NumericBox : UserControl
{
public NumericBox()
{
InitializeComponent();
}
public uint? Value
{
get => (uint?)GetValue(ValueProperty);
set => SetValue(ValueProperty, value);
}
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register("Value", typeof(uint?), typeof(NumericBox), new PropertyMetadata(null));
The UserControl contains others controls witch interract with Value property (+/-) and it works fine.
But I create the DependencyProperty to also bind the value in parent page.
A exemple of code in a page where I inject the UserControl :
var binding = new Binding("Line.Quantity");
binding.Mode = BindingMode.TwoWay;
var numeric = new NumericBox();
numeric.SetBinding(ValueProperty, binding);
The binding works on startup but not update Line.Quantity when I modify the Textbox...
The Line class implements INotifyPropertyChanged and notify change on Quantity.
What is the correct way to do that ?
I have seen this question but but I have not been able to correct my code :
Binding on DependencyProperty of custom User Control not updating on change
I've created a custom control, means a class deriving from control associating a default lookless theme defined via Themes/Generic.xaml. So far so good.
Now, I want to use the control like any other of the main WPF-controls (textbox, listbox, label, textblock, ...) and bind to the defined properties.
The custom control defines a property called Value, that I like to set a Binding to. But nothing ever is written to the bound property in the DataContext.
Well, here's what I've got so far:
In Custom Control class, there is as follows:
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register(
"Value", typeof(string), typeof(MyClass),
new FrameworkPropertyMetadata("", new PropertyChangedCallback(onValuePropertyChangedCallback)));
private static void onValuePropertyChangedCallback(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
MyClass myClass = (MyClass)sender;
myClass.Value = (string)args.NewValue;
}
public string Value
{
get { return (string) GetValue(ValueProperty); }
set { SetValue(ValueProperty, value); }
}
When I use the control, it's like that
<local:MyClass MyValue="{Binding CurrentValue}" ... />
The CurrentValue-property of the DataContext is never affected, never changes it's value.
What am I doing wrong?
The Binding to should be two-way in order to update the source property:
<local:MyClass Value="{Binding CurrentValue, Mode=TwoWay}" ... />
If you want this to be the default binding mode, you could set an appropriate flag when you register your property:
public static readonly DependencyProperty ValueProperty = DependencyProperty.Register(
nameof(Value), typeof(string), typeof(MyClass),
new FrameworkPropertyMetadata(
"", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
public string Value
{
get { return (string)GetValue(ValueProperty); }
set { SetValue(ValueProperty, value); }
}
Note that your onValuePropertyChangedCallback was entirely redundant. You don't need to set the property again, when its value has just changed.
I have a Custom user control in a silver light Project.
I use it in other page and want to Pass textbox to Custom User control.
For this I create dependcy as below :
public static readonly DependencyProperty MyPropertyProperty = DependencyProperty.Register("TextBoxControl", typeof(TextBox), typeof(SpellCheck), new PropertyMetadata(false));
public TextBox TextBoxControl
{
get { return (TextBox)GetValue(MyPropertyProperty); }
set
{
SetValue(MyPropertyProperty, value);
TextSpell = value;
}
}
Here TextSpell is a textbox.
And I use this property in a silver light page as below:
<TextBox x:Name="txtNote" Grid.Row="3" Grid.Column="1" HorizontalAlignment="Left" VerticalAlignment="Stretch" Width="400"/>
<myButton:SpellCheck x:Name="btnSpell" Grid.Row="3" TextBoxControl="txtNote" Grid.Column="1" Width="20" Height="20" Margin="403,0,0,0" HorizontalAlignment="Left"/>
But I give s me a error : "The Typeconvertor for Texbox dose not support converting from a string"
So How can I pass a text box in custom usercontrol.
Thanks,
Hitesh
You can not simply use the field name (x:Name) string of the TextBox as a value for your TextBoxControl property. Instead you may use an ElementName binding like this:
<myButton:SpellCheck TextBoxControl="{Binding ElementName=txtNote}" ... />
And there are more things wrong:
In the CLR wrappers of a dependency property, you should never call anything else than GetValue and SetValue. The explanation is given in the XAML Loading and Dependency Properties article on MSDN. Instead, you have to have a PropertyChangedCallback registered with the property metadata.
There is a naming convention for the static dependency property fields. They should be named like the property, with a trailing Property.
The default value has to match the property type. Your false value is not valid, and might be null instead. But as that is the default anyway, you should leave it out completely.
The declaration would now look like this:
public static readonly DependencyProperty TextBoxControlProperty =
DependencyProperty.Register(
"TextBoxControl", typeof(TextBox), typeof(SpellCheck),
new PropertyMetadata(TextBoxControlPropertyChanged));
public TextBox TextBoxControl
{
get { return (TextBox)GetValue(TextBoxControlProperty); }
set { SetValue(TextBoxControlProperty, value); }
}
private static void TextBoxControlPropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var spellCheck = (SpellCheck)obj;
spellCheck.TextSpell = (TextBox)e.NewValue;
}
I have a custom text box defined as follows:
public class CustomTextBox : TextBox
{
public static DependencyProperty CustomTextProperty =
DependencyProperty.Register("CustomText", typeof(string),
typeof(CustomTextBox));
static CustomTextBox()
{
TextProperty.OverrideMetadata(typeof(SMSTextBox),
new FrameworkPropertyMetadata(string.Empty,
FrameworkPropertyMetadataOptions.Journal |
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
new PropertyChangedCallback(CustomTextBox_OnTextPropertyChanged));
}
public string CustomText
{
get { return (string)GetValue(CustomTextProperty); }
set { SetValue(CustomTextProperty, value); }
}
private static void CustomTextBox_OnTextPropertyChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
CustomTextBox customTextBox = d as CustomTextBox;
customTextBox.SetValue(CustomTextProperty, e.NewValue);
}
}
I'm binding the Custom Text property in the XAML -
<local:CustomTextBox CustomText="{Binding ViewModelProperty}" />
The problem I'm facing is that when I enter anything in the CustomTextBox, the changes are not reflected in the ViewModelProperty i.e. the ViewModelProperty is not getting updated. The CustomTextProperty is getting updated but I suppose I need to do something extra to make the binding work as well.
What am I not doing? I would appreciate any help regarding this.
Thank you
I guess the binding needs to be two-way.
<local:CustomTextBox
CustomText="{Binding ViewModelProperty, Mode=TwoWay}" />
You wouldn't need to specify the Mode if you made the CustomText property bind two-way by default:
public static readonly DependencyProperty CustomTextProperty =
DependencyProperty.Register(
"CustomText", typeof(string), typeof(CustomTextBox),
new FrameworkPropertyMetadata(
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
You may also have to define a PropertyChangedCallback for the CustomText property that updates the Text property (i.e. the other direction of what you have implemented now). Otherwise the TextBox won't display anything that is initially contained in the ViewModel property and of course woudln't be updated when the ViewModel property changes.
I have created a custom TextBox control (but not derived from TextBox) that contains a Dependency Property "Text".
I have added an instance of this and bound it to a property on my view model using a TwoWay binding.
From within my custom TextBox control, how do I update the Text property in such a way that the change is propagated to the property on the view model?
If I set the "Text" property on my custom control, that replaces the binding leaving the property on the view model as null.
I would have thought this would be simple but I can't see how to do it (the standard TextBox control must do it!)
Cheers
Edit:
Custom Control:
public class SampleCustomControl : CustomControl
{
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(SampleCustomControl), new PropertyMetadata(null));
public void Update()
{
// This replaces my binding, I want it to pass the new value
// through to the "SomeProperty" two way binding.
Text = "some value";
}
}
Usage:
<Controls:SampleCustomControl Text="{Binding SomeProperty, Mode=TwoWay}" />
You need to add a Property Changed callback in the metadata of your dependency property.
This callback will be fired when the Text property changes (from either side). You can use the value passed in from this to update your custom UI that you've built to display the text.
Update:
Responding to your comment about what this is about. Since your example code is too vague to test, here is what I used to test your problem.
public class TestControl : ContentControl
{
private TextBlock _tb;
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
_tb = new TextBlock();
_tb.Text = Text;
this.Content = _tb;
_tb.MouseLeftButtonDown += new MouseButtonEventHandler(_tb_MouseLeftButtonDown);
}
void _tb_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
Update();
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(TestControl), new PropertyMetadata(string.Empty, OnTextChanged));
public void Update()
{
// This replaces my binding, I want it to pass the new value
// through to the "SomeProperty" two way binding.
Text = "some value";
}
public static void OnTextChanged(object sender, DependencyPropertyChangedEventArgs e)
{
((TestControl)sender).UpdateText((string)e.NewValue);
}
protected void UpdateText(string text)
{
if (_tb != null) _tb.Text = text;
}
}
I then bound the Text property on my control to the view model using a two way binding. When I click the text in the view both the view and the viewmodel get updated with the new text "some value". If I update the value in the viewmodel (and raise the property changed event) the value gets updated in the view and the control so the binding is still valid.
There must be some other missing pieces in your example.
As long as your binding property is set to TwoWay and you have exposed the getter and the setter, than the text you enter in the TextBox is sent to the ViewModel. I believe the actual send occurs when you lose focus of that control however, i believe.