filterinfo.cs

一种.net实现ajax方法的类库

/** Copyright (c) 2006, All-In-One Creations, Ltd.
*  All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
*     * Neither the name of All-In-One Creations, Ltd. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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**/
/**
 * Project: emergetk: stateful web framework for the masses
 * File name: FilterInfo.cs
 * Description: filter defininition for RecordLists.
 *   
 * Author: Ben Joldersma
 *   
 */

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace EmergeTk.Model
{
    public enum FilterOperation
    {
        GreaterThan,
        LessThan,
        Equals,
        DoesNotEqual,
        In,
        NotIn
    }

    public class FilterInfo
    {
        public string ColumnName;
        public object Value;
        public FilterOperation Operation;

        public FilterInfo(string columnName, object value, FilterOperation op)
        {
            ColumnName = columnName;
            Value = value;
            Operation = op;
        }

        public static bool Filter(FilterOperation op, object lvalue, object rvalue)
        {
            bool isMatch = false;
            switch (op)
            {
                case FilterOperation.Equals:
                case FilterOperation.GreaterThan:
                case FilterOperation.LessThan:
                case FilterOperation.DoesNotEqual:
                    if (lvalue.GetType() != rvalue.GetType())
                    {
                        try
                        {
                            rvalue = PropertyConverter.Convert(rvalue, lvalue.GetType());
                        }
                        catch
                        {
                            if (op == FilterOperation.DoesNotEqual)
                                return true;
                        }
                    }
                    IComparable l = lvalue as IComparable;
                    IComparable r = rvalue as IComparable;
                    int result = l.CompareTo( r );
                    if( result == 0 )
                        isMatch = op == FilterOperation.Equals;
                    else if( result < 0 )
                        isMatch = op == FilterOperation.LessThan || op == FilterOperation.DoesNotEqual;
                    else
                        isMatch = op == FilterOperation.GreaterThan || op == FilterOperation.DoesNotEqual;
                    break;
                case FilterOperation.In:
                case FilterOperation.NotIn:
                    if (rvalue is IList)
                    {
                        IList list = rvalue as IList;
                        isMatch = list.Contains(lvalue);
                    }
                    else if (rvalue is string)
                    {
                        isMatch = rvalue.ToString().Contains(lvalue.ToString());
                    }
                    if (op == FilterOperation.NotIn) isMatch = !isMatch;
                    break;
            }
            return isMatch;
        }

        public override string ToString()
        {
            string v = Value.ToString();
            if (Value is string || Value is DataType || Value is Enum)
            {
                v = "'" + Value.ToString().Replace("'", "''") + "'";
            }
            return string.Format("{0} {1} {2}", ColumnName, FilterOperationToString(Operation), v);
        }

        static public string FilterOperationToString(FilterOperation op)
        {
            string symbol = "UNK";
            switch (op)
            {
                case FilterOperation.Equals:
                    symbol = "=";
                    break;
                case FilterOperation.DoesNotEqual:
                    symbol = "<>";
                    break;
                case FilterOperation.GreaterThan:
                    symbol = ">";
                    break;
                case FilterOperation.LessThan:
                    symbol = "<";
                    break;
                case FilterOperation.In:
                    symbol = "IN";
                    break;
                case FilterOperation.NotIn:
                    symbol = "NOT IN";
                    break;
            }
            return symbol;
        }
    }
}