I try to add converter to ResourceDictionary because I need to use it, but when only I add declariation an error occur when I run the app.
This is how add converter declaration:
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:System="clr-namespace:System;assembly=mscorlib"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:Command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WP71"
xmlns:converters="clr-namespace:Sample.Utility.Converters">
<converters:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter"/>
And this is a error I received
{System.Windows.Markup.XamlParseException: The type 'BoolToVisibilityConverter' was not found. [Line: 17 Position: 44]
at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
at Sample.App.InitializeComponent()
at Sample.App..ctor()}
I event tried to add the converter to , but the result as the same.
Can any help me with my problem, please ?
this is code of my Converter
public class BoolToVisibilityConverter : IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
bool visible = (bool)value;
return (visible ? Visibility.Visible : Visibility.Collapsed);
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
Visibility vis = (Visibility)value;
switch (vis)
{
case Visibility.Collapsed:
return false;
case Visibility.Visible:
return true;
}
return null;
}
#endregion
}
To have a resource dictionary available globally in your app, you need to merge it like this in your App.xaml:
<Application x:Class="Sample.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/uri/to/resource_dictionary.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
Related
I have a converter
using System.Globalization;
namespace WidgetsForRuntimeInjection.Converters
{
public class SampleBooleanConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{ ... }
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{ ... }
}
}
and a view
<?xml version="1.0" encoding="utf-8" ?>
<ResourceDictionary xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:viewModels="clr-namespace:WidgetsForRuntimeInjection.ViewModels"
xmlns:converters="clr-namespace:WidgetsForRuntimeInjection.Converters;assembly=WidgetsForRuntimeInjection"
x:Class="WidgetsForRuntimeInjection.Views.SampleWidgetsForInjection">
<converters:SampleBooleanConverter x:Key="SampleBooleanConverter"/>
<DataTemplate x:DataType="viewModels:SwitchViewModel" x:Key="SwitchDataTemplate">
<Switch IsToggled="{Binding Value, Converter={StaticResource SampleBooleanConverter}}" IsEnabled="{Binding ReadWrite}"/>
</DataTemplate>
</ResourceDictionary>
both of them are in a single assembly that is build as dll.
Then in another assembly I am loading it and adding to an application resources.
var assembly = Assembly.LoadFile( ... path to dll... );
var resources = assembly.CreateInstance("WidgetsForRuntimeInjection.Views.SampleWidgetsForInjection");
App.Current.Resources.Add("SwitchDataTemplate", (resources as ResourceDictionary)["SwitchDataTemplate"]);
And I got error like that:
Microsoft.Maui.Controls.Xaml.XamlParseException: 'Position 7:6. Type converters:SampleBooleanConverter not found in xmlns clr-namespace:WidgetsForRuntimeInjection.Converters;assembly=WidgetsForRuntimeInjection'
But I can create an instance of this converter a line before (in this second assembly).
var converter = assembly.CreateInstance("WidgetsForRuntimeInjection.Converters.SampleBooleanConverter");
And of course with no converter scenario it all works like a charm.
How to make it work? I tried do Converter as DynamicResource and declaring namespace for converters differently.
UPDATE:
That is kind of weird, because it seems to work after I have added same in alternative way - in xaml.cs file like below:
public partial class SampleWidgetsForInjection : ResourceDictionary
{
public SampleWidgetsForInjection()
{
this.Add("SampleBooleanToColorConverter", new SampleBooleanToColorConverter());
InitializeComponent();
}
}
So it seems this is a workaround / solution:
public partial class SampleWidgetsForInjection : ResourceDictionary
{
public SampleWidgetsForInjection()
{
this.Add("SampleBooleanToColorConverter", new SampleBooleanToColorConverter());
InitializeComponent();
}
}
I have a Image in my xaml in which the source is a URL that Iam binding.The URL from json will be like this : "/images/Uploads/e0111.png". I have the URL in my Common values stored class as CommonValues.URL. How can I add this "CommonValues.URL" before the json at the time of binding? So that the source for Image will be http://example.com//images/Uploads/e0111.png.?
If you need Uri
var myUrl= new Uri(CommonValues.URL + "images/Uploads/e0111.png");
If string than
var myUrl=CommonValues.URL + "images/Uploads/e0111.png";
Or you can do it like this in your ViewModel or Page
public string Url => string.Format("{0}{1}", CommonValues.URL,"/images/Uploads/e0111.png");
Then in XAML:
<Button Text="{Binding Url}"/>
You can use a converter, which will allow you to reuse in all your views/application
public class UrlConverter : IValueConverter
{
#region IValueConverter implementation
public object Convert (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
var test = value as string;
if (!string.IsNullOrEmpty(test))
{
return CommonValues.URL + test;
}
return false;
}
public object ConvertBack (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException ();
}
#endregion
}
Then, in your page:
<ContentPage.Resources>
<ResourceDictionary>
<converter:UrlConverter x:Key="UrlConverter" />
</ResourceDictionary>
</ContentPage.Resources>
<Image Source="{Binding YourProperty, Converter={StaticResource UrlConverter}}"/>
I am using XAML to define a ListView, with multiple buttons for each cell.
I want to trigger visibility depending on whether a string value is empty or not.
My button inside the ListView is:
<Button Text="{Binding Phone}"
Clicked="OnPhoneClicked"
CommandParameter="{Binding Telefono}"
x:Name="btnPhone" />
Binding Phone is read from my model. It is correctly shown.
How can set a IsVisible property button if Phone's value is an empty string?
Try this code
<Button Text="{Binding Phone}"
Clicked="OnPhoneClicked"
CommandParameter="{Binding Telefono}"
x:Name="btnPhone"
IsVisible="{Binding Phone,Converter={StaticResource StringNullOrEmptyBoolConverter"} />
StringNullOrEmptyBoolConverter.cs file
public class StringNullOrEmptyBoolConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
var s = value as string;
return !string.IsNullOrWhiteSpace(s);
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
Finally add this in App.xaml file
<Application.Resources>
<ResourceDictionary>
<Converter:StringNullOrEmptyBoolConverter x:Key="StringNullOrEmptyBoolConverter" />
</ResourceDictionary>
</Application.Resources>
How I can add : with string at my label in xaml in xamarin.forms. I have a text coming from app resource file by (i18n:Translate Text=Supplier). Now with this text I also add : after this text. I don't want to add : in app resource with text. I want to do that it on xaml only. I tried with StringFormat but don't know how I can do it.
You can use a Value Converter to change the value on your Binding, but it's tricky because you can't easily add a converter while using i18n:Translate. But I still see three possible solutions to your problem:
1. Property without Value Converter
The easiest way would be to create a Property which gets the translated text and then adds a colon to your text:
ViewModel:
public string Supplier
{
get { return AppResources.Supplier + ":"; }
}
XAML:
<Label Text="{Binding Supplier}"/>
2. Property with Value converter
Another way is to create a property which gets the translated text and then add the colon via a Value Converter:
ViewModel:
public string Supplier
{
get { return AppResources.Supplier; }
}
Converter class:
public class ColonConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return value += ":";
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return value.ToString().Remove(value.ToString().Length - 1);
}
}
XAML:
<ContentPage.Resources>
<ResourceDictionary>
<local:ColonConverter x:Key="ColonConverter" />
</ResourceDictionary>
</ContentPage.Resources>
...
<Label Text={Binding Supplier, Converter={StaticResource ColonConverter}}"/>
3. Create your own Translate Extension and Value Converter
I didn't test this, but I found this SO answer which gives an example on how to achieve that. This way you don't need to add properties to your ViewModel, so you only have to adjust your XAML once you set up the Translate Extension and Converter. But it's needs some work to write your own Translate Extension.
Custom TranslateExtension:
[ContentProperty("Text")]
public class TranslateExtension : IMarkupExtension
{
const string ResourceId = "Project.Resources.AppResources";
public string Text { get; set; }
public IValueConverter Converter { get; set; }
public object ProvideValue(IServiceProvider serviceProvider)
{
if (Text == null)
return null;
ResourceManager resourceManager = new ResourceManager(ResourceId, typeof(TranslateExtension).GetTypeInfo().Assembly);
string translatedText = resourceManager.GetString(Text, CultureInfo.CurrentCulture);
if (this.Converter != null)
{
translatedText = Converter.Convert(translatedText, typeof(string), null, CultureInfo.CurrentCulture).ToString() ?? translatedText;
}
return translatedText;
}
}
XAML:
xmlns:strings="clr-namespace:Project.Utils;assembly=Project"
<ContentPage.Resources>
<ResourceDictionary>
<converters:ColonSpaceConverter x:Key="ColonSpaceConverter" />
</ResourceDictionary>
</ContentPage.Resources>
<Label Text="{strings:Translate Money, Converter={StaticResource ColonSpaceConverter}}" />
This can be achieved in many ways, drafting two of them: (Value of Label will be changed on sliding the Slider)
Method 1
<Label Text="Slide to change Value"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand"
x:Name="lblSliderValue" FontSize="Title" Margin="60"></Label>
<Slider ValueChanged="Slider_ValueChanged"></Slider>
And in CodeBehind file,
private void Slider_ValueChanged(object sender, ValueChangedEventArgs e)
{
lblSliderValue.Text = e.NewValue.ToString("0.00");
lblSliderValue.BackgroundColor = Color.Black;
lblSliderValue.TextColor = Color.White;
}
Method 2 (No need of code in CodeBehind file)
<Label Text="Slide to change Value"
VerticalOptions="Center"
HorizontalOptions="Center"
Text="{Binding Source={x:Reference sldExample}, Path=Value, StringFormat='{0:F2}'}"></Label>
<Slider x:Name="sldExample" BackgroundColor="Yellow" ThumbColor="Violet"></Slider>
i am trying to set the slider control to value from text block's text property through {Binding} on XAML.
<Slider ValueChanged="slider_ValueChanged_1" Value= "{Binding ElementName=ComponentTextBlockValue,Path=Text}" StepFrequency="25"/>
Do i need an converter to set the slider's value . The binding seems to work sometimes but sometimes it doesn't work. Sometimes,the slider just doesn't set its value to text block value.
Since you bind the Slider's value directly without a value converter, I suspect that the binding is broken when the text is not a number or out of range.
You can prevent that by creating a value converter that will prevent bad value to be bound, so the binding will always work.
Here is some example:
public class TextToSliderValueConverter : IValueConverter
{
public double MaximumSliderValue { get; set; }
public double MinimumSliderValue { get; set; }
public object Convert(object value, Type targetType, object parameter, string language)
{
double sliderValue;
if (double.TryParse(value as string, out sliderValue)
&& sliderValue <= MaximumSliderValue && sliderValue >= MinimumSliderValue)
{
return sliderValue;
}
else
{
return 0.0;
}
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{
throw new NotImplementedException();
}
}
Here is the XAML:
<Page
x:Class="stovfSliderTextBox.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:stovfSliderTextBox"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<local:TextToSliderValueConverter x:Key="txtToSliderValue" MaximumSliderValue="100" MinimumSliderValue="0"/>
</Page.Resources>
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<StackPanel>
<Slider Value= "{Binding ElementName=ComponentTextBlockValue,Path=Text, Converter={StaticResource txtToSliderValue}, ConverterParameter=slider}" StepFrequency="25"/>
<TextBox x:Name="ComponentTextBlockValue" Width="50"/>
</StackPanel>
</Grid>
</Page>
The TextToSliderValueConverter makes sure that the slider will always get the valid value. If you do not use default Slider.Maximum or Slider.Minimum, you can modify the values accordingly.
Hope this helps!