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//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
// File: LengthConverter.cs
//
// Description: Contains the LengthConverter: TypeConverter for the Length class.
//
// History:
// 06/27/2003 : wwilaria - Initial implementation
//
//---------------------------------------------------------------------------
using System;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Globalization;
using System.Reflection;
using System.Windows;
using System.Windows.Markup;
using System.Security;
using MS.Internal;
using MS.Utility;
namespace System.Windows
{
/// <summary>
/// LengthConverter - Converter class for converting instances of other types to and from double representing length.
/// </summary>
public class LengthConverter: TypeConverter
{
//-------------------------------------------------------------------
//
// Public Methods
//
//-------------------------------------------------------------------
#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 length from the given object
/// </summary>
/// <returns>
/// The double representing the size in 1/96th of an inch.
/// </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 double.
/// </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 double. </param>
public override object ConvertFrom(ITypeDescriptorContext typeDescriptorContext,
CultureInfo cultureInfo,
object source)
{
if (source != null)
{
if (source is string) { return FromString((string)source, cultureInfo); }
else { return (double)(Convert.ToDouble(source, cultureInfo)); }
}
throw GetConvertFromException(source);
}
/// <summary>
/// ConvertTo - Attempt to convert a double to the given type
/// </summary>
/// <returns>
/// The object 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 object is not null,
/// 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 double to convert. </param>
/// <param name="destinationType">The type to which to convert the double. </param>
///<SecurityNote>
/// Critical: calls InstanceDescriptor ctor which LinkDemands
/// PublicOK: can only make an InstanceDescriptor for double, not an arbitrary class
///</SecurityNote>
[SecurityCritical]
public override object ConvertTo(ITypeDescriptorContext typeDescriptorContext,
CultureInfo cultureInfo,
object value,
Type destinationType)
{
if (destinationType == null)
{
throw new ArgumentNullException("destinationType");
}
if ( value != null
&& value is double )
{
double l = (double)value;
if (destinationType == typeof(string))
{
if(DoubleUtil.IsNaN(l))
return "Auto";
else
return Convert.ToString(l, cultureInfo);
}
else if (destinationType == typeof(InstanceDescriptor))
{
ConstructorInfo ci = typeof(double).GetConstructor(new Type[] { typeof(double) });
return new InstanceDescriptor(ci, new object[] { l });
}
}
throw GetConvertToException(value, destinationType);
}
#endregion
//-------------------------------------------------------------------
//
// Internal Methods
//
//-------------------------------------------------------------------
#region Internal Methods
// Parse a Length from a string given the CultureInfo.
// Formats:
//"[value][unit]"
// [value] is a double
// [unit] is a string specifying the unit, like 'in' or 'px', or nothing (means pixels)
// NOTE - This code is called from FontSizeConverter, so changes will affect both.
static internal double FromString(string s, CultureInfo cultureInfo)
{
string valueString = s.Trim();
string goodString = valueString.ToLowerInvariant();
int strLen = goodString.Length;
int strLenUnit = 0;
double unitFactor = 1.0;
//Auto is represented and Double.NaN
//properties that do not want Auto and NaN to be in their ligit values,
//should disallow NaN in validation callbacks (same goes for negative values)
if (goodString == "auto") return Double.NaN;
for (int i = 0; i < PixelUnitStrings.Length; i++)
{
// NOTE: This is NOT a culture specific comparison.
// This is by design: we want the same unit string table to work across all cultures.
if (goodString.EndsWith(PixelUnitStrings[i], StringComparison.Ordinal))
{
strLenUnit = PixelUnitStrings[i].Length;
unitFactor = PixelUnitFactors[i];
break;
}
}
// important to substring original non-lowered string
// this allows case sensitive ToDouble below handle "NaN" and "Infinity" correctly.
// this addresses windows bug 1177408
valueString = valueString.Substring(0, strLen - strLenUnit);
// FormatException errors thrown by Convert.ToDouble are pretty uninformative.
// Throw a more meaningful error in this case that tells that we were attempting
// to create a Length instance from a string. This addresses windows bug 968884
try
{
double result = Convert.ToDouble(valueString, cultureInfo) * unitFactor;
return result;
}
catch (FormatException)
{
throw new FormatException(SR.Get(SRID.LengthFormatError, valueString));
}
}
// This array contains strings for unit types
// These are effectively "TypeConverter only" units.
// They are all expressable in terms of the Pixel unit type and a conversion factor.
static private string[] PixelUnitStrings = { "px", "in", "cm", "pt" };
static private double[] PixelUnitFactors =
{
1.0, // Pixel itself
96.0, // Pixels per Inch
96.0 / 2.54, // Pixels per Centimeter
96.0 / 72.0, // Pixels per Point
};
static internal string ToString(double l, CultureInfo cultureInfo)
{
if(DoubleUtil.IsNaN(l)) return "Auto";
return Convert.ToString(l, cultureInfo);
}
#endregion
}
}
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