// Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the MIT license. // // Description: Virtualization cache length converter implementation // using MS.Internal; using System.ComponentModel; using System.ComponentModel.Design.Serialization; using System.Globalization; using System.Reflection; namespace System.Windows.Controls { /// <summary> /// VirtualizationCacheLengthConverter - Converter class for converting /// instances of other types to and from VirtualizationCacheLength instances. /// </summary> public class VirtualizationCacheLengthConverter : TypeConverter { #region Public Methods /// <summary> /// CanConvertFrom - Returns whether or not this class can convert from a given type. /// </summary> /// <returns> /// bool - True if thie converter can convert from the provided type, false if not. /// </returns> /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param> /// <param name="sourceType"> The Type being queried for support. </param> public override bool CanConvertFrom(ITypeDescriptorContext typeDescriptorContext, Type sourceType) { // We can only handle strings, integral and floating types TypeCode tc = Type.GetTypeCode(sourceType); switch (tc) { case TypeCode.String: case TypeCode.Decimal: case TypeCode.Single: case TypeCode.Double: case TypeCode.Int16: case TypeCode.Int32: case TypeCode.Int64: case TypeCode.UInt16: case TypeCode.UInt32: case TypeCode.UInt64: return true; default: return false; } } /// <summary> /// CanConvertTo - Returns whether or not this class can convert to a given type. /// </summary> /// <returns> /// bool - True if this converter can convert to the provided type, false if not. /// </returns> /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param> /// <param name="destinationType"> The Type being queried for support. </param> public override bool CanConvertTo(ITypeDescriptorContext typeDescriptorContext, Type destinationType) { // We can convert to an InstanceDescriptor or to a string. if ( destinationType == typeof(InstanceDescriptor) || destinationType == typeof(string)) { return true; } else { return false; } } /// <summary> /// ConvertFrom - Attempt to convert to a VirtualizationCacheLength from the given object /// </summary> /// <returns> /// The VirtualizationCacheLength which was constructed. /// </returns> /// <exception cref="ArgumentNullException"> /// An ArgumentNullException is thrown if the example object is null. /// </exception> /// <exception cref="ArgumentException"> /// An ArgumentException is thrown if the example object is not null and is not a valid type /// which can be converted to a VirtualizationCacheLength. /// </exception> /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param> /// <param name="cultureInfo"> The CultureInfo which is respected when converting. </param> /// <param name="source"> The object to convert to a VirtualizationCacheLength. </param> public override object ConvertFrom(ITypeDescriptorContext typeDescriptorContext, CultureInfo cultureInfo, object source) { if (source != null) { if (source is string) { return (FromString((string)source, cultureInfo)); } else { // conversion from numeric type double value = Convert.ToDouble(source, cultureInfo); return new VirtualizationCacheLength(value); } } throw GetConvertFromException(source); } /// <summary> /// ConvertTo - Attempt to convert a VirtualizationCacheLength to the given type /// </summary> /// <returns> /// The object which was constructoed. /// </returns> /// <exception cref="ArgumentNullException"> /// An ArgumentNullException is thrown if the example object is null. /// </exception> /// <exception cref="ArgumentException"> /// An ArgumentException is thrown if the object is not null and is not a VirtualizationCacheLength, /// or if the destinationType isn't one of the valid destination types. /// </exception> /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param> /// <param name="cultureInfo"> The CultureInfo which is respected when converting. </param> /// <param name="value"> The VirtualizationCacheLength to convert. </param> /// <param name="destinationType">The type to which to convert the VirtualizationCacheLength instance. </param> public override object ConvertTo(ITypeDescriptorContext typeDescriptorContext, CultureInfo cultureInfo, object value, Type destinationType) { ArgumentNullException.ThrowIfNull(destinationType); if (value != null && value is VirtualizationCacheLength) { VirtualizationCacheLength gl = (VirtualizationCacheLength)value; if (destinationType == typeof(string)) { return (ToString(gl, cultureInfo)); } if (destinationType == typeof(InstanceDescriptor)) { ConstructorInfo ci = typeof(VirtualizationCacheLength).GetConstructor(new Type[] { typeof(double), typeof(VirtualizationCacheLengthUnit) }); return (new InstanceDescriptor(ci, new object[] { gl.CacheBeforeViewport, gl.CacheAfterViewport })); } } throw GetConvertToException(value, destinationType); } #endregion Public Methods //------------------------------------------------------------------- // // Internal Methods // //------------------------------------------------------------------- #region Internal Methods /// <summary> /// Creates a string from a VirtualizationCacheLength given the CultureInfo. /// </summary> /// <param name="cacheLength">VirtualizationCacheLength.</param> /// <param name="cultureInfo">Culture Info.</param> /// <returns>Newly created string instance.</returns> internal static string ToString(VirtualizationCacheLength cacheLength, CultureInfo cultureInfo) { char listSeparator = TokenizerHelper.GetNumericListSeparator(cultureInfo); return string.Create(cultureInfo, stackalloc char[128], $"{cacheLength.CacheBeforeViewport}{listSeparator}{cacheLength.CacheAfterViewport}"); } /// <summary> /// Parses a VirtualizationCacheLength from a string given the CultureInfo. /// </summary> /// <param name="s">String to parse from.</param> /// <param name="cultureInfo">Culture Info.</param> /// <returns>Newly created VirtualizationCacheLength instance.</returns> internal static VirtualizationCacheLength FromString(string s, CultureInfo cultureInfo) { TokenizerHelper th = new TokenizerHelper(s, cultureInfo); double[] lengths = new double[2]; int i = 0; // Peel off each double in the delimited list. while (th.NextToken()) { if (i >= 2) { i = 3; // Set i to a bad value. break; } lengths[i] = Double.Parse(th.GetCurrentToken(), cultureInfo); i++; } // We have a reasonable interpreation for one value (all four edges), two values (horizontal, vertical), // and four values (left, top, right, bottom). switch (i) { case 1: return new VirtualizationCacheLength(lengths[0]); case 2: // Should allowInfinity be false ??? (Rob) return new VirtualizationCacheLength(lengths[0], lengths[1]); } throw new FormatException(SR.Format(SR.InvalidStringVirtualizationCacheLength, s)); } #endregion } } |