mcs/class/System.Web/System.Web.Compilation/AppSettingsExpressionBuilder.cs

   1 //
   2 // System.Web.Compilation.AppSettingsExpressionBuilder
   3 //
   4 // Authors:
   5 //      Chris Toshok (toshok@ximian.com)
   6 //
   7 // (C) 2006-2009 Novell, Inc (http://www.novell.com)
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31
  32 using System;
  33 using System.CodeDom;
  34 using System.ComponentModel;
  35 using System.Configuration;
  36 using System.Web.Configuration;
  37 using System.Web.UI;
  38 using System.Reflection;
  39
  40 namespace System.Web.Compilation
  41 {
  42         [ExpressionEditor("System.Web.UI.Design.AppSettingsExpressionEditor, " + Consts.AssemblySystem_Design)]
  43         [ExpressionPrefix("AppSettings")]
  44         public class AppSettingsExpressionBuilder : ExpressionBuilder
  45         {
  46                 public override object EvaluateExpression (object target, BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context)
  47                 {
  48                         return GetAppSetting (entry.Expression.Trim ());
  49                 }
  50
  51                 public static object GetAppSetting (string key)
  52                 {
  53                         string value = WebConfigurationManager.AppSettings [key];
  54
  55                         if (value == null)
  56                                 throw new InvalidOperationException (String.Format ("The application setting '{0}' was not found.", key));
  57                         return value;
  58                 }
  59
  60                 public static object GetAppSetting (string key, Type targetType, string propertyName)
  61                 {
  62                         object value = GetAppSetting (key);
  63
  64                         if (targetType == null)
  65                                 return value.ToString ();
  66
  67                         PropertyInfo pi = targetType.GetProperty(propertyName);
  68                         if (pi == null)
  69                                 return value.ToString ();
  70
  71                         try {
  72                                 TypeConverter converter = TypeDescriptor.GetConverter (pi.PropertyType);
  73                                 return converter.ConvertFrom (value);
  74                         } catch (NotSupportedException) {
  75                                 throw new InvalidOperationException (String.Format (
  76                                         "Could not convert application setting '{0}' " +
  77                                         " to type '{1}' for property '{2}'.", value,
  78                                         pi.PropertyType.Name, pi.Name));
  79                         }
  80                 }
  81
  82                 public override CodeExpression GetCodeExpression (BoundPropertyEntry entry, object parsedData, ExpressionBuilderContext context)
  83                 {
  84                         Type type = entry.DeclaringType;
  85                         PropertyDescriptor descriptor = TypeDescriptor.GetProperties(type)[entry.PropertyInfo.Name];
  86                         CodeExpression[] expressionArray = new CodeExpression[3];
  87                         expressionArray[0] = new CodePrimitiveExpression(entry.Expression.Trim());
  88                         expressionArray[1] = new CodeTypeOfExpression(entry.Type);
  89                         expressionArray[2] = new CodePrimitiveExpression(entry.Name);
  90                         return new CodeCastExpression(descriptor.PropertyType, new CodeMethodInvokeExpression(new
  91                                                                        CodeTypeReferenceExpression(base.GetType()), "GetAppSetting", expressionArray));
  92                 }
  93
  94                 public override bool SupportsEvaluate {
  95                         get { return true; }
  96                 }
  97         }
  98
  99 }
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