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#nullable disable
using System;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
namespace Microsoft.Maui.Controls
{
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="Type[@FullName='Microsoft.Maui.Controls.TemplateBinding']/Docs/*" />
[Obsolete("Use Binding.Source=RelativeBindingSource.TemplatedParent")]
[RequiresUnreferencedCode(TrimmerConstants.StringPathBindingWarning, Url = TrimmerConstants.ExpressionBasedBindingsDocsUrl)]
public sealed class TemplateBinding : BindingBase
{
internal const string SelfPath = ".";
IValueConverter _converter;
object _converterParameter;
BindingExpression _expression;
string _path;
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="//Member[@MemberName='.ctor'][1]/Docs/*" />
public TemplateBinding()
{
}
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="//Member[@MemberName='.ctor']/Docs/*" />
public TemplateBinding(string path, BindingMode mode = BindingMode.Default, IValueConverter converter = null, object converterParameter = null, string stringFormat = null)
{
if (path == null)
throw new ArgumentNullException(nameof(path));
if (string.IsNullOrWhiteSpace(path))
throw new ArgumentException("path cannot be an empty string", nameof(path));
AllowChaining = true;
Path = path;
Converter = converter;
ConverterParameter = converterParameter;
Mode = mode;
StringFormat = stringFormat;
}
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="//Member[@MemberName='Converter']/Docs/*" />
public IValueConverter Converter
{
get { return _converter; }
set
{
ThrowIfApplied();
_converter = value;
}
}
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="//Member[@MemberName='ConverterParameter']/Docs/*" />
public object ConverterParameter
{
get { return _converterParameter; }
set
{
ThrowIfApplied();
_converterParameter = value;
}
}
/// <include file="../../docs/Microsoft.Maui.Controls/TemplateBinding.xml" path="//Member[@MemberName='Path']/Docs/*" />
public string Path
{
get { return _path; }
set
{
ThrowIfApplied();
_path = value;
_expression = GetBindingExpression(value);
}
}
internal override void Apply(bool fromTarget)
{
base.Apply(fromTarget);
if (_expression == null)
_expression = new BindingExpression(this, SelfPath);
_expression.Apply(fromTarget);
}
internal override async void Apply(object newContext, BindableObject bindObj, BindableProperty targetProperty, bool fromBindingContextChanged, SetterSpecificity specificity)
{
var view = bindObj as Element;
if (view == null)
throw new InvalidOperationException();
base.Apply(newContext, bindObj, targetProperty, fromBindingContextChanged, specificity);
Element templatedParent = await TemplateUtilities.FindTemplatedParentAsync(view);
ApplyInner(templatedParent, bindObj, targetProperty);
}
internal override BindingBase Clone()
{
var clone = new TemplateBinding(Path, Mode) { Converter = Converter, ConverterParameter = ConverterParameter, StringFormat = StringFormat };
if (VisualDiagnostics.IsEnabled && VisualDiagnostics.GetSourceInfo(this) is SourceInfo info)
VisualDiagnostics.RegisterSourceInfo(clone, info.SourceUri, info.LineNumber, info.LinePosition);
return clone;
}
internal override object GetSourceValue(object value, Type targetPropertyType)
{
if (Converter != null)
value = Converter.Convert(value, targetPropertyType, ConverterParameter, CultureInfo.CurrentUICulture);
return base.GetSourceValue(value, targetPropertyType);
}
internal override object GetTargetValue(object value, Type sourcePropertyType)
{
if (Converter != null)
value = Converter.ConvertBack(value, sourcePropertyType, ConverterParameter, CultureInfo.CurrentUICulture);
return base.GetTargetValue(value, sourcePropertyType);
}
internal override void Unapply(bool fromBindingContextChanged = false)
{
base.Unapply(fromBindingContextChanged: fromBindingContextChanged);
if (_expression != null)
_expression.Unapply();
}
void ApplyInner(Element templatedParent, BindableObject bindableObject, BindableProperty targetProperty)
{
if (_expression == null && templatedParent != null)
_expression = new BindingExpression(this, SelfPath);
_expression?.Apply(templatedParent, bindableObject, targetProperty, SetterSpecificity.FromBinding);
}
BindingExpression GetBindingExpression(string path)
{
return new BindingExpression(this, !string.IsNullOrWhiteSpace(path) ? path : SelfPath);
}
}
} |