897 lines
26 KiB
C#

using System;
using Csla.Properties;
namespace Csla
{
/// <summary>
/// Provides a date data type that understands the concept
/// of an empty date value.
/// </summary>
/// <remarks>
/// See Chapter 5 for a full discussion of the need for this
/// data type and the design choices behind it.
/// </remarks>
[Serializable()]
public struct SmartDate : IComparable
{
private DateTime _date;
private bool _initialized;
private EmptyValue _emptyValue;
private string _format;
private static string _defaultFormat;
#region EmptyValue enum
/// <summary>
/// Indicates the empty value of a
/// SmartDate.
/// </summary>
public enum EmptyValue
{
/// <summary>
/// Indicates that an empty SmartDate
/// is the smallest date.
/// </summary>
MinDate,
/// <summary>
/// Indicates that an empty SmartDate
/// is the largest date.
/// </summary>
MaxDate
}
#endregion
#region Constructors
static SmartDate()
{
_defaultFormat = "d";
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(bool emptyIsMin)
{
_emptyValue = GetEmptyValue(emptyIsMin);
_format = null;
_initialized = false;
// provide a dummy value to allow real initialization
_date = DateTime.MinValue;
SetEmptyDate(_emptyValue);
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="emptyValue">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(EmptyValue emptyValue)
{
_emptyValue = emptyValue;
_format = null;
_initialized = false;
// provide a dummy value to allow real initialization
_date = DateTime.MinValue;
SetEmptyDate(_emptyValue);
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <remarks>
/// The SmartDate created will use the min possible
/// date to represent an empty date.
/// </remarks>
/// <param name="value">The initial value of the object.</param>
public SmartDate(DateTime value)
{
_emptyValue = Csla.SmartDate.EmptyValue.MinDate;
_format = null;
_initialized = false;
_date = DateTime.MinValue;
Date = value;
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="value">The initial value of the object.</param>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(DateTime value, bool emptyIsMin)
{
_emptyValue = GetEmptyValue(emptyIsMin);
_format = null;
_initialized = false;
_date = DateTime.MinValue;
Date = value;
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="value">The initial value of the object.</param>
/// <param name="emptyValue">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(DateTime value, EmptyValue emptyValue)
{
_emptyValue = emptyValue;
_format = null;
_initialized = false;
_date = DateTime.MinValue;
Date = value;
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <remarks>
/// The SmartDate created will use the min possible
/// date to represent an empty date.
/// </remarks>
/// <param name="value">The initial value of the object (as text).</param>
public SmartDate(string value)
{
_emptyValue = EmptyValue.MinDate;
_format = null;
_initialized = true;
_date = DateTime.MinValue;
this.Text = value;
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="value">The initial value of the object (as text).</param>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(string value, bool emptyIsMin)
{
_emptyValue = GetEmptyValue(emptyIsMin);
_format = null;
_initialized = true;
_date = DateTime.MinValue;
this.Text = value;
}
/// <summary>
/// Creates a new SmartDate object.
/// </summary>
/// <param name="value">The initial value of the object (as text).</param>
/// <param name="emptyValue">Indicates whether an empty date is the min or max date value.</param>
public SmartDate(string value, EmptyValue emptyValue)
{
_emptyValue = emptyValue;
_format = null;
_initialized = true;
_date = DateTime.MinValue;
this.Text = value;
}
private static EmptyValue GetEmptyValue(bool emptyIsMin)
{
if (emptyIsMin)
return EmptyValue.MinDate;
else
return EmptyValue.MaxDate;
}
private void SetEmptyDate(EmptyValue emptyValue)
{
if (emptyValue == SmartDate.EmptyValue.MinDate)
this.Date = DateTime.MinValue;
else
this.Date = DateTime.MaxValue;
}
#endregion
#region Text Support
/// <summary>
/// Sets the global default format string used by all new
/// SmartDate values going forward.
/// </summary>
/// <remarks>
/// The default global format string is "d" unless this
/// method is called to change that value. Existing SmartDate
/// values are unaffected by this method, only SmartDate
/// values created after calling this method are affected.
/// </remarks>
/// <param name="formatString">
/// The format string should follow the requirements for the
/// .NET System.String.Format statement.
/// </param>
public static void SetDefaultFormatString(string formatString)
{
_defaultFormat = formatString;
}
/// <summary>
/// Gets or sets the format string used to format a date
/// value when it is returned as text.
/// </summary>
/// <remarks>
/// The format string should follow the requirements for the
/// .NET System.String.Format statement.
/// </remarks>
/// <value>A format string.</value>
public string FormatString
{
get
{
if (_format == null)
_format = _defaultFormat;
return _format;
}
set
{
_format = value;
}
}
/// <summary>
/// Gets or sets the date value.
/// </summary>
/// <remarks>
/// <para>
/// This property can be used to set the date value by passing a
/// text representation of the date. Any text date representation
/// that can be parsed by the .NET runtime is valid.
/// </para><para>
/// When the date value is retrieved via this property, the text
/// is formatted by using the format specified by the
/// <see cref="FormatString" /> property. The default is the
/// short date format (d).
/// </para>
/// </remarks>
public string Text
{
get { return DateToString(this.Date, FormatString, _emptyValue); }
set { this.Date = StringToDate(value, _emptyValue); }
}
#endregion
#region Date Support
/// <summary>
/// Gets or sets the date value.
/// </summary>
public DateTime Date
{
get
{
if (!_initialized)
{
_date = DateTime.MinValue;
_initialized = true;
}
return _date;
}
set
{
_date = value;
_initialized = true;
}
}
#endregion
#region System.Object overrides
/// <summary>
/// Returns a text representation of the date value.
/// </summary>
public override string ToString()
{
return this.Text;
}
/// <summary>
/// Returns a text representation of the date value.
/// </summary>
/// <param name="format">
/// A standard .NET format string.
/// </param>
public string ToString(string format)
{
return DateToString(this.Date, format, _emptyValue);
}
/// <summary>
/// Compares this object to another <see cref="SmartDate"/>
/// for equality.
/// </summary>
/// <param name="obj">Object to compare for equality.</param>
public override bool Equals(object obj)
{
if (obj is SmartDate)
{
SmartDate tmp = (SmartDate)obj;
if (this.IsEmpty && tmp.IsEmpty)
return true;
else
return this.Date.Equals(tmp.Date);
}
else if (obj is DateTime)
return this.Date.Equals((DateTime)obj);
else if (obj is string)
return (this.CompareTo(obj.ToString()) == 0);
else
return false;
}
/// <summary>
/// Returns a hash code for this object.
/// </summary>
public override int GetHashCode()
{
return this.Date.GetHashCode();
}
#endregion
#region DBValue
/// <summary>
/// Gets a database-friendly version of the date value.
/// </summary>
/// <remarks>
/// <para>
/// If the SmartDate contains an empty date, this returns <see cref="DBNull"/>.
/// Otherwise the actual date value is returned as type Date.
/// </para><para>
/// This property is very useful when setting parameter values for
/// a Command object, since it automatically stores null values into
/// the database for empty date values.
/// </para><para>
/// When you also use the SafeDataReader and its GetSmartDate method,
/// you can easily read a null value from the database back into a
/// SmartDate object so it remains considered as an empty date value.
/// </para>
/// </remarks>
public object DBValue
{
get
{
if (this.IsEmpty)
return DBNull.Value;
else
return this.Date;
}
}
#endregion
#region Empty Dates
/// <summary>
/// Gets a value indicating whether this object contains an empty date.
/// </summary>
public bool IsEmpty
{
get
{
if (_emptyValue == EmptyValue.MinDate)
return this.Date.Equals(DateTime.MinValue);
else
return this.Date.Equals(DateTime.MaxValue);
}
}
/// <summary>
/// Gets a value indicating whether an empty date is the
/// min or max possible date value.
/// </summary>
/// <remarks>
/// Whether an empty date is considered to be the smallest or largest possible
/// date is only important for comparison operations. This allows you to
/// compare an empty date with a real date and get a meaningful result.
/// </remarks>
public bool EmptyIsMin
{
get { return (_emptyValue == EmptyValue.MinDate); }
}
#endregion
#region Conversion Functions
/// <summary>
/// Converts a string value into a SmartDate.
/// </summary>
/// <param name="value">String containing the date value.</param>
/// <returns>A new SmartDate containing the date value.</returns>
/// <remarks>
/// EmptyIsMin will default to <see langword="true"/>.
/// </remarks>
public static SmartDate Parse(string value)
{
return new SmartDate(value);
}
/// <summary>
/// Converts a string value into a SmartDate.
/// </summary>
/// <param name="value">String containing the date value.</param>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
/// <returns>A new SmartDate containing the date value.</returns>
public static SmartDate Parse(string value, bool emptyIsMin)
{
return new SmartDate(value, emptyIsMin);
}
/// <summary>
/// Converts a text date representation into a Date value.
/// </summary>
/// <remarks>
/// An empty string is assumed to represent an empty date. An empty date
/// is returned as the MinValue of the Date datatype.
/// </remarks>
/// <param name="value">The text representation of the date.</param>
/// <returns>A Date value.</returns>
public static DateTime StringToDate(string value)
{
return StringToDate(value, true);
}
/// <summary>
/// Converts a text date representation into a Date value.
/// </summary>
/// <remarks>
/// An empty string is assumed to represent an empty date. An empty date
/// is returned as the MinValue or MaxValue of the Date datatype depending
/// on the EmptyIsMin parameter.
/// </remarks>
/// <param name="value">The text representation of the date.</param>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
/// <returns>A Date value.</returns>
public static DateTime StringToDate(string value, bool emptyIsMin)
{
return StringToDate(value, GetEmptyValue(emptyIsMin));
}
/// <summary>
/// Converts a text date representation into a Date value.
/// </summary>
/// <remarks>
/// An empty string is assumed to represent an empty date. An empty date
/// is returned as the MinValue or MaxValue of the Date datatype depending
/// on the EmptyIsMin parameter.
/// </remarks>
/// <param name="value">The text representation of the date.</param>
/// <param name="emptyValue">Indicates whether an empty date is the min or max date value.</param>
/// <returns>A Date value.</returns>
public static DateTime StringToDate(string value, EmptyValue emptyValue)
{
DateTime tmp;
if (String.IsNullOrEmpty(value))
{
if (emptyValue == EmptyValue.MinDate)
return DateTime.MinValue;
else
return DateTime.MaxValue;
}
else if (DateTime.TryParse(value, out tmp))
return tmp;
else
{
string ldate = value.Trim().ToLower();
if (ldate == Resources.SmartDateT ||
ldate == Resources.SmartDateToday ||
ldate == ".")
return DateTime.Now;
if (ldate == Resources.SmartDateY ||
ldate == Resources.SmartDateYesterday ||
ldate == "-")
return DateTime.Now.AddDays(-1);
if (ldate == Resources.SmartDateTom ||
ldate == Resources.SmartDateTomorrow ||
ldate == "+")
return DateTime.Now.AddDays(1);
throw new ArgumentException(Resources.StringToDateException);
}
}
/// <summary>
/// Converts a date value into a text representation.
/// </summary>
/// <remarks>
/// The date is considered empty if it matches the min value for
/// the Date datatype. If the date is empty, this
/// method returns an empty string. Otherwise it returns the date
/// value formatted based on the FormatString parameter.
/// </remarks>
/// <param name="value">The date value to convert.</param>
/// <param name="formatString">The format string used to format the date into text.</param>
/// <returns>Text representation of the date value.</returns>
public static string DateToString(
DateTime value, string formatString)
{
return DateToString(value, formatString, true);
}
/// <summary>
/// Converts a date value into a text representation.
/// </summary>
/// <remarks>
/// Whether the date value is considered empty is determined by
/// the EmptyIsMin parameter value. If the date is empty, this
/// method returns an empty string. Otherwise it returns the date
/// value formatted based on the FormatString parameter.
/// </remarks>
/// <param name="value">The date value to convert.</param>
/// <param name="formatString">The format string used to format the date into text.</param>
/// <param name="emptyIsMin">Indicates whether an empty date is the min or max date value.</param>
/// <returns>Text representation of the date value.</returns>
public static string DateToString(
DateTime value, string formatString, bool emptyIsMin)
{
return DateToString(value, formatString, GetEmptyValue(emptyIsMin));
}
/// <summary>
/// Converts a date value into a text representation.
/// </summary>
/// <remarks>
/// Whether the date value is considered empty is determined by
/// the EmptyIsMin parameter value. If the date is empty, this
/// method returns an empty string. Otherwise it returns the date
/// value formatted based on the FormatString parameter.
/// </remarks>
/// <param name="value">The date value to convert.</param>
/// <param name="formatString">The format string used to format the date into text.</param>
/// <param name="emptyValue">Indicates whether an empty date is the min or max date value.</param>
/// <returns>Text representation of the date value.</returns>
public static string DateToString(
DateTime value, string formatString, EmptyValue emptyValue)
{
if (emptyValue == EmptyValue.MinDate)
{
if (value == DateTime.MinValue)
return string.Empty;
}
else
{
if (value == DateTime.MaxValue)
return string.Empty;
}
return string.Format("{0:" + formatString + "}", value);
}
#endregion
#region Manipulation Functions
/// <summary>
/// Compares one SmartDate to another.
/// </summary>
/// <remarks>
/// This method works the same as the DateTime.CompareTo method
/// on the Date datetype, with the exception that it
/// understands the concept of empty date values.
/// </remarks>
/// <param name="value">The date to which we are being compared.</param>
/// <returns>A value indicating if the comparison date is less than, equal to or greater than this date.</returns>
public int CompareTo(SmartDate value)
{
if (this.IsEmpty && value.IsEmpty)
return 0;
else
return _date.CompareTo(value.Date);
}
/// <summary>
/// Compares one SmartDate to another.
/// </summary>
/// <remarks>
/// This method works the same as the DateTime.CompareTo method
/// on the Date datetype, with the exception that it
/// understands the concept of empty date values.
/// </remarks>
/// <param name="value">The date to which we are being compared.</param>
/// <returns>A value indicating if the comparison date is less than, equal to or greater than this date.</returns>
int IComparable.CompareTo(object value)
{
if (value is SmartDate)
return CompareTo((SmartDate)value);
else
throw new ArgumentException(Resources.ValueNotSmartDateException);
}
/// <summary>
/// Compares a SmartDate to a text date value.
/// </summary>
/// <param name="value">The date to which we are being compared.</param>
/// <returns>A value indicating if the comparison date is less than, equal to or greater than this date.</returns>
public int CompareTo(string value)
{
return this.Date.CompareTo(StringToDate(value, _emptyValue));
}
/// <summary>
/// Compares a SmartDate to a date value.
/// </summary>
/// <param name="value">The date to which we are being compared.</param>
/// <returns>A value indicating if the comparison date is less than, equal to or greater than this date.</returns>
public int CompareTo(DateTime value)
{
return this.Date.CompareTo(value);
}
/// <summary>
/// Adds a TimeSpan onto the object.
/// </summary>
/// <param name="value">Span to add to the date.</param>
public DateTime Add(TimeSpan value)
{
if (IsEmpty)
return this.Date;
else
return this.Date.Add(value);
}
/// <summary>
/// Subtracts a TimeSpan from the object.
/// </summary>
/// <param name="value">Span to subtract from the date.</param>
public DateTime Subtract(TimeSpan value)
{
if (IsEmpty)
return this.Date;
else
return this.Date.Subtract(value);
}
/// <summary>
/// Subtracts a DateTime from the object.
/// </summary>
/// <param name="value">Date to subtract from the date.</param>
public TimeSpan Subtract(DateTime value)
{
if (IsEmpty)
return TimeSpan.Zero;
else
return this.Date.Subtract(value);
}
#endregion
#region Operators
/// <summary>
/// Equality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator ==(SmartDate obj1, SmartDate obj2)
{
return obj1.Equals(obj2);
}
/// <summary>
/// Inequality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator !=(SmartDate obj1, SmartDate obj2)
{
return !obj1.Equals(obj2);
}
/// <summary>
/// Equality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator ==(SmartDate obj1, DateTime obj2)
{
return obj1.Equals(obj2);
}
/// <summary>
/// Inequality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator !=(SmartDate obj1, DateTime obj2)
{
return !obj1.Equals(obj2);
}
/// <summary>
/// Equality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator ==(SmartDate obj1, string obj2)
{
return obj1.Equals(obj2);
}
/// <summary>
/// Inequality operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator !=(SmartDate obj1, string obj2)
{
return !obj1.Equals(obj2);
}
/// <summary>
/// Addition operator
/// </summary>
/// <param name="start">Original date/time</param>
/// <param name="span">Span to add</param>
/// <returns></returns>
public static SmartDate operator +(SmartDate start, TimeSpan span)
{
return new SmartDate(start.Add(span), start.EmptyIsMin);
}
/// <summary>
/// Subtraction operator
/// </summary>
/// <param name="start">Original date/time</param>
/// <param name="span">Span to subtract</param>
/// <returns></returns>
public static SmartDate operator -(SmartDate start, TimeSpan span)
{
return new SmartDate(start.Subtract(span), start.EmptyIsMin);
}
/// <summary>
/// Subtraction operator
/// </summary>
/// <param name="start">Original date/time</param>
/// <param name="finish">Second date/time</param>
/// <returns></returns>
public static TimeSpan operator -(SmartDate start, SmartDate finish)
{
return start.Subtract(finish.Date);
}
/// <summary>
/// Greater than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >(SmartDate obj1, SmartDate obj2)
{
return obj1.CompareTo(obj2) > 0;
}
/// <summary>
/// Less than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <(SmartDate obj1, SmartDate obj2)
{
return obj1.CompareTo(obj2) < 0;
}
/// <summary>
/// Greater than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >(SmartDate obj1, DateTime obj2)
{
return obj1.CompareTo(obj2) > 0;
}
/// <summary>
/// Less than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <(SmartDate obj1, DateTime obj2)
{
return obj1.CompareTo(obj2) < 0;
}
/// <summary>
/// Greater than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >(SmartDate obj1, string obj2)
{
return obj1.CompareTo(obj2) > 0;
}
/// <summary>
/// Less than operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <(SmartDate obj1, string obj2)
{
return obj1.CompareTo(obj2) < 0;
}
/// <summary>
/// Greater than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >=(SmartDate obj1, SmartDate obj2)
{
return obj1.CompareTo(obj2) >= 0;
}
/// <summary>
/// Less than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <=(SmartDate obj1, SmartDate obj2)
{
return obj1.CompareTo(obj2) <= 0;
}
/// <summary>
/// Greater than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >=(SmartDate obj1, DateTime obj2)
{
return obj1.CompareTo(obj2) >= 0;
}
/// <summary>
/// Less than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <=(SmartDate obj1, DateTime obj2)
{
return obj1.CompareTo(obj2) <= 0;
}
/// <summary>
/// Greater than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator >=(SmartDate obj1, string obj2)
{
return obj1.CompareTo(obj2) >= 0;
}
/// <summary>
/// Less than or equals operator
/// </summary>
/// <param name="obj1">First object</param>
/// <param name="obj2">Second object</param>
/// <returns></returns>
public static bool operator <=(SmartDate obj1, string obj2)
{
return obj1.CompareTo(obj2) <= 0;
}
#endregion
}
}