sdk/samples/all in on code/Visual Studio 2010/CSDynamicallyBuildLambdaExpressionWithField/DynamicCondition/SimulateVal.cs

   1 /********************************** Module Header **********************************\
   2 * Module Name:  SimulateVal.cs
   3 * Project:      CSDynamicallyBuildLambdaExpressionWithField
   4 * Copyright (c) Microsoft Corporation.
   5 *
   6 * The SimulateVal.cs file defines variant function which is deal with DateTime and Boolean.
   7 *
   8 * This source is subject to the Microsoft Public License.
   9 * See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  10 * All other rights reserved.
  11 *
  12 * THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
  13 * EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
  14 * MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  15 \***********************************************************************************/
  16
  17 public static class SimulateVal
  18 {
  19     public static double Val(string expression)
  20     {
  21         if (expression == null)
  22         {
  23             return 0;
  24         }
  25         // Try the entire string, then progressively smaller
  26         // substrings to simulate the behavior of VB's 'Val',
  27         // which ignores trailing characters after a recognizable value:
  28         for (int size = expression.Length; size > 0; size--)
  29         {
  30             double testDouble;
  31             if (double.TryParse(expression.Substring(0, size), out testDouble))
  32                 return testDouble;
  33         }
  34
  35         // No value is recognized, so return 0:
  36         return 0;
  37     }
  38
  39     public static double Val(object expression)
  40     {
  41         if (expression == null)
  42         {
  43             return 0;
  44         }
  45
  46         double testDouble;
  47         if (double.TryParse(expression.ToString(), out testDouble))
  48         {
  49             return testDouble;
  50         }
  51         // CSharp's 'Val' function returns -1 for 'true':
  52         bool testBool;
  53
  54         if (bool.TryParse(expression.ToString(), out testBool))
  55         {
  56             return testBool ? -1 : 0;
  57         }
  58         // CSharp's 'Val' function returns the day of the month for dates:
  59         System.DateTime testDate;
  60         if (System.DateTime.TryParse(expression.ToString(), out testDate))
  61         {
  62             return testDate.Day;
  63         }
  64         // No value is recognized, so return 0:
  65         return 0;
  66
  67     }
  68
  69     /// <summary>
  70     /// Convert char into string
  71     /// </summary>
  72     public static int Val(char expression)
  73     {
  74         int testInt;
  75         if (int.TryParse(expression.ToString(), out testInt))
  76         {
  77             return testInt;
  78         }
  79         else
  80         {
  81             return 0;
  82         }
  83     }
  84 }