System.Convert.DefaultToType C# (CSharp) Method

        internal static Object DefaultToType(IConvertible value, Type targetType, IFormatProvider provider) {
            BCLDebug.Assert(value!=null, "[Convert.DefaultToType]value!=null");

            if (targetType==null) {
                throw new ArgumentNullException("targetType");
            }
            
            if (value.GetType()==targetType) {
                return value;
            }

            if (targetType==ConvertTypes[(int)TypeCode.Boolean])
                return value.ToBoolean(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Char])
                return value.ToChar(provider);
            if (targetType==ConvertTypes[(int)TypeCode.SByte])
                return value.ToSByte(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Byte])
                return value.ToByte(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Int16]) 
                return value.ToInt16(provider);
            if (targetType==ConvertTypes[(int)TypeCode.UInt16])
                return value.ToUInt16(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Int32])
                return value.ToInt32(provider);
            if (targetType==ConvertTypes[(int)TypeCode.UInt32])
                return value.ToUInt32(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Int64])
                return value.ToInt64(provider);
            if (targetType==ConvertTypes[(int)TypeCode.UInt64])
                return value.ToUInt64(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Single])
                return value.ToSingle(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Double])
                return value.ToDouble(provider);
            if (targetType==ConvertTypes[(int)TypeCode.Decimal])
                return value.ToDecimal(provider);
            if (targetType==ConvertTypes[(int)TypeCode.DateTime])
                return value.ToDateTime(provider);
            if (targetType==ConvertTypes[(int)TypeCode.String]) {
                return value.ToString(provider);
            }
            if (targetType==ConvertTypes[(int)TypeCode.Object])
                return (Object)value;
            if (targetType==ConvertTypes[(int)TypeCode.DBNull])
                throw new InvalidCastException(Environment.GetResourceString("InvalidCast_DBNull"));
            if (targetType==ConvertTypes[(int)TypeCode.Empty]) 
                throw new InvalidCastException(Environment.GetResourceString("InvalidCast_Empty"));
            throw new InvalidCastException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidCast_FromTo"), value.GetType().FullName, targetType.FullName));
        }

 Object IConvertible.ToType(Type type, IFormatProvider provider)
 {
     return(Convert.DefaultToType((IConvertible)this, type, provider));
 }