/// <summary>
/// Performs several special conversions allowed by NUnit in order to
/// permit arguments with types that cannot be used in the constructor
/// of an Attribute such as TestCaseAttribute or to simplify their use.
/// </summary>
/// <param name="value">The value to be converted</param>
/// <param name="targetType">The target <see cref="Type"/> in which the <paramref name="value"/> should be converted</param>
/// <param name="convertedValue">If conversion was successfully applied, the <paramref name="value"/> converted into <paramref name="targetType"/></param>
/// <returns>
/// <c>true</c> if <paramref name="value"/> was converted and <paramref name="convertedValue"/> should be used;
/// <c>false</c> is no conversion was applied and <paramref name="convertedValue"/> should be ignored
/// </returns>
public static bool TryConvert(object value, Type targetType, out object convertedValue)
{
if (targetType.IsInstanceOfType(value))
{
convertedValue = value;
return(true);
}
if (value == null || value.GetType().FullName == "System.DBNull")
{
convertedValue = null;
return(Reflect.IsAssignableFromNull(targetType));
}
bool convert = false;
var underlyingTargetType = Nullable.GetUnderlyingType(targetType) ?? targetType;
if (underlyingTargetType == typeof(short) || underlyingTargetType == typeof(byte) || underlyingTargetType == typeof(sbyte) ||
underlyingTargetType == typeof(long) || underlyingTargetType == typeof(double))
{
convert = value is int;
}
else if (underlyingTargetType == typeof(decimal))
{
convert = value is double || value is string || value is int;
}
else if (underlyingTargetType == typeof(DateTime))
{
convert = value is string;
}
if (convert)
{
convertedValue = System.Convert.ChangeType(value, underlyingTargetType, CultureInfo.InvariantCulture);
return(true);
}
var converter = TypeDescriptor.GetConverter(underlyingTargetType);
if (converter.CanConvertFrom(value.GetType()))
{
convertedValue = converter.ConvertFrom(null, CultureInfo.InvariantCulture, value);
return(true);
}
convertedValue = null;
return(false);
}
/// <summary>
/// Converts a single value to the <paramref name="targetType"/>, if it is supported.
/// </summary>
public static bool TryConvert(object value, Type targetType, out object convertedValue)
{
if (targetType.IsInstanceOfType(value))
{
convertedValue = value;
return(true);
}
if (value == null || value.GetType().FullName == "System.DBNull")
{
convertedValue = null;
return(Reflect.IsAssignableFromNull(targetType));
}
bool convert = false;
if (targetType == typeof(short) || targetType == typeof(byte) || targetType == typeof(sbyte))
{
convert = value is int;
}
else if (targetType == typeof(decimal))
{
convert = value is double || value is string || value is int;
}
else if (targetType == typeof(DateTime) || targetType == typeof(TimeSpan))
{
convert = value is string;
}
if (convert)
{
convertedValue = System.Convert.ChangeType(value, targetType, System.Globalization.CultureInfo.InvariantCulture);
return(true);
}
convertedValue = null;
return(false);
}
