| File: System\Windows\Forms\Controls\Labels\LinkArea.LinkAreaConverter.cs | Web Access |
| Project: src\winforms\src\System.Windows.Forms\System.Windows.Forms.csproj (System.Windows.Forms) |
// Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. using System.Collections; using System.ComponentModel; using System.ComponentModel.Design.Serialization; using System.Globalization; namespace System.Windows.Forms; public partial struct LinkArea { /// <summary> /// LinkAreaConverter is a class that can be used to convert LinkArea from one data type /// to another. Access this class through the TypeDescriptor. /// </summary> public class LinkAreaConverter : TypeConverter { /// <summary> /// Determines if this converter can convert an object in the given source /// type to the native type of the converter. /// </summary> public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType) { if (sourceType == typeof(string)) { return true; } return base.CanConvertFrom(context, sourceType); } /// <summary> /// Gets a value indicating whether this converter can convert an object to the /// given destination type using the context. /// </summary> public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType) { if (destinationType == typeof(InstanceDescriptor)) { return true; } return base.CanConvertTo(context, destinationType); } /// <summary> /// Converts the given object to the converter's native type. /// </summary> public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value) { if (value is string valueStr) { ReadOnlySpan<char> text = valueStr.AsSpan().Trim(); if (text.IsEmpty) { return null; } // Parse 2 integer values. culture ??= CultureInfo.CurrentCulture; Span<int> values = stackalloc int[2]; if (!TypeConverterHelper.TryParseAsSpan(context, culture, text, values)) { throw new ArgumentException( string.Format( SR.TextParseFailedFormat, valueStr, "start, length")); } return new LinkArea(values[0], values[1]); } return base.ConvertFrom(context, culture, value); } /// <summary> /// Converts the given object to another type. The most common types to convert /// are to and from a string object. The default implementation will make a call /// to ToString on the object if the object is valid and if the destination /// type is string. If this cannot convert to the destination type, this will /// throw a NotSupportedException. /// </summary> public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType) { if (value is LinkArea pt) { if (destinationType == typeof(string)) { culture ??= CultureInfo.CurrentCulture; string sep = culture.TextInfo.ListSeparator + " "; TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int)); string?[] args = [ intConverter.ConvertToString(context, culture, pt.Start), intConverter.ConvertToString(context, culture, pt.Length) ]; return string.Join(sep, args); } else if (destinationType == typeof(InstanceDescriptor)) { return new InstanceDescriptor( typeof(LinkArea).GetConstructor([typeof(int), typeof(int)]), new object[] { pt.Start, pt.Length }); } } return base.ConvertTo(context, culture, value, destinationType); } /// <summary> /// Creates an instance of this type given a set of property values /// for the object. This is useful for objects that are immutable, but still /// want to provide changeable properties. /// </summary> public override object CreateInstance(ITypeDescriptorContext? context, IDictionary propertyValues) { ArgumentNullException.ThrowIfNull(propertyValues); try { return new LinkArea( (int)propertyValues[nameof(Start)]!, (int)propertyValues[nameof(Length)]!); } catch (InvalidCastException invalidCast) { throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), invalidCast); } catch (NullReferenceException nullRef) { throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), nullRef); } } /// <summary> /// Determines if changing a value on this object should require a call to /// CreateInstance to create a new value. /// </summary> public override bool GetCreateInstanceSupported(ITypeDescriptorContext? context) => true; /// <summary> /// Retrieves the set of properties for this type. By default, a type has /// does not return any properties. An easy implementation of this method /// can just call TypeDescriptor.GetProperties for the correct data type. /// </summary> [RequiresUnreferencedCode(TrimmingConstants.TypeConverterGetPropertiesMessage)] public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext? context, object value, Attribute[]? attributes) { PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(LinkArea), attributes); return props.Sort([nameof(Start), nameof(Length)]); } /// <summary> /// Determines if this object supports properties. By default, this is false. /// </summary> public override bool GetPropertiesSupported(ITypeDescriptorContext? context) => true; } }