wpftoolkit/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/DateTimeUpDown/Implementation/DateTimeParser.cs

/************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   This program can be provided to you by Xceed Software Inc. under a
   proprietary commercial license agreement for use in non-Open Source
   projects. The commercial version of Extended WPF Toolkit also includes
   priority technical support, commercial updates, and many additional 
   useful WPF controls if you license Xceed Business Suite for WPF.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

namespace Xceed.Wpf.Toolkit
{
  internal class DateTimeParser
  {
    public static bool TryParse( string value, string format, DateTime currentDate, CultureInfo cultureInfo, out DateTime result )
    {
      bool success = false;
      result = currentDate;

      if( string.IsNullOrEmpty( value ) || string.IsNullOrEmpty( format ) )
        return false;

      var dateTimeString = ResolveDateTimeString( value, format, currentDate, cultureInfo ).Trim();

      if( !String.IsNullOrEmpty( dateTimeString ) )
        success = DateTime.TryParse( dateTimeString, cultureInfo.DateTimeFormat, DateTimeStyles.None, out result );

      if( !success )
        result = currentDate;

      return success;
    }

    private static string ResolveDateTimeString( string dateTime, string format, DateTime currentDate, CultureInfo cultureInfo )
    {
      Dictionary<string, string> dateParts = GetDateParts( currentDate, cultureInfo );
      string[] timeParts = new string[ 3 ] { currentDate.Hour.ToString(), currentDate.Minute.ToString(), currentDate.Second.ToString() };
      string designator = "";
      string[] dateTimeSeparators = new string[] { ",", " ", "-", ".", "/", cultureInfo.DateTimeFormat.DateSeparator, cultureInfo.DateTimeFormat.TimeSeparator };

      ResolveSortableDateTimeString( ref dateTime, ref format, cultureInfo );

      var dateTimeParts = dateTime.Split( dateTimeSeparators, StringSplitOptions.RemoveEmptyEntries ).ToList();
      var formats = format.Split( dateTimeSeparators, StringSplitOptions.RemoveEmptyEntries ).ToList();

      //something went wrong
      if( dateTimeParts.Count != formats.Count )
        return string.Empty;

      for( int i = 0; i < formats.Count; i++ )
      {
        var f = formats[ i ];
        if( !f.Contains( "ddd" ) && !f.Contains( "GMT" ) )
        {
          if( f.Contains( "M" ) )
            dateParts[ "Month" ] = dateTimeParts[ i ];
          else if( f.Contains( "d" ) )
            dateParts[ "Day" ] = dateTimeParts[ i ];
          else if( f.Contains( "y" ) )
          {
            dateParts[ "Year" ] = dateTimeParts[ i ];

            if( dateParts[ "Year" ].Length == 2 )
              dateParts[ "Year" ] = string.Format( "{0}{1}", currentDate.Year / 100, dateParts[ "Year" ] );
          }
          else if( f.Contains( "h" ) || f.Contains( "H" ) )
            timeParts[ 0 ] = dateTimeParts[ i ];
          else if( f.Contains( "m" ) )
            timeParts[ 1 ] = dateTimeParts[ i ];
          else if( f.Contains( "s" ) )
            timeParts[ 2 ] = dateTimeParts[ i ];
          else if( f.Contains( "t" ) )
            designator = dateTimeParts[ i ];
        }
      }

      var date = string.Join( cultureInfo.DateTimeFormat.DateSeparator, dateParts.Select( x => x.Value ).ToArray() );
      var time = string.Join( cultureInfo.DateTimeFormat.TimeSeparator, timeParts );

      return String.Format( "{0} {1} {2}", date, time, designator );
    }

    private static void ResolveSortableDateTimeString( ref string dateTime, ref string format, CultureInfo cultureInfo )
    {
      if( format == cultureInfo.DateTimeFormat.SortableDateTimePattern )
      {
        format = format.Replace( "'", "" ).Replace( "T", " " );
        dateTime = dateTime.Replace( "'", "" ).Replace( "T", " " );
      }
      else if( format == cultureInfo.DateTimeFormat.UniversalSortableDateTimePattern )
      {
        format = format.Replace( "'", "" ).Replace( "Z", "" );
        dateTime = dateTime.Replace( "'", "" ).Replace( "Z", "" );
      }
    }

    private static Dictionary<string, string> GetDateParts( DateTime currentDate, CultureInfo cultureInfo )
    {
      Dictionary<string, string> dateParts = new Dictionary<string, string>();
      var dateFormatParts = cultureInfo.DateTimeFormat.ShortDatePattern.Split( new string[] { cultureInfo.DateTimeFormat.DateSeparator }, StringSplitOptions.RemoveEmptyEntries ).ToList();
      dateFormatParts.ForEach( item =>
      {
        string key = string.Empty;
        string value = string.Empty;

        if( item.Contains( "M" ) )
        {
          key = "Month";
          value = currentDate.Month.ToString();
        }
        else if( item.Contains( "d" ) )
        {
          key = "Day";
          value = currentDate.Day.ToString();
        }
        else if( item.Contains( "y" ) )
        {
          key = "Year";
          value = currentDate.Year.ToString();
        }
        dateParts.Add( key, value );
      } );
      return dateParts;
    }
  }
}