mcs/class/System.Web/System.Web.UI/DataBinder.cs

   1 //
   2 // System.Web.UI.DataBinder.cs
   3 //
   4 // Authors:
   5 //      Duncan Mak  (duncan@ximian.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (C) 2002 Ximian, Inc. (http://www.ximian.com)
   9 //
  10
  11 using System;
  12 using System.Collections;
  13 using System.ComponentModel;
  14 using System.Reflection;
  15
  16 namespace System.Web.UI {
  17
  18         public sealed class DataBinder
  19         {
  20                 public DataBinder ()
  21                 {
  22                 }
  23
  24                 private static string FormatResult (object result, string format)
  25                 {
  26                         if (result == null)
  27                                 return String.Empty;
  28
  29                         if (format == null)
  30                                 return result.ToString ();
  31
  32                         return String.Format (format, result);
  33                 }
  34
  35                 public static object Eval (object container, string expression)
  36                 {
  37                         if (expression == null)
  38                                 throw new ArgumentNullException ("expression");
  39
  40                         object current = container;
  41
  42                         while (current != null) {
  43                                 int dot = expression.IndexOf ('.');
  44                                 int size = (dot == -1) ? expression.Length : dot;
  45                                 string prop = expression.Substring (0, size);
  46                                 if (prop.IndexOf ('[') != -1)
  47                                         current = GetIndexedPropertyValue (current, prop);
  48                                 else
  49                                         current = GetPropertyValue (current, prop);
  50
  51                                 if (dot == -1)
  52                                         break;
  53
  54                                 expression = expression.Substring (prop.Length + 1);
  55                         }
  56
  57                         return current;
  58                 }
  59
  60                 public static string Eval (object container, string expression, string format)
  61                 {
  62                         object result = Eval (container, expression);
  63                         return FormatResult (result, format);
  64                 }
  65
  66                 public static object GetIndexedPropertyValue (object container, string expr)
  67                 {
  68                         if (expr == null)
  69                                 throw new ArgumentNullException ("expr");
  70
  71                         int openIdx = expr.IndexOf ('[');
  72                         int closeIdx = expr.IndexOf (']'); // see the test case. MS ignores all after the first ]
  73                         if (openIdx < 0 || closeIdx < 0 || closeIdx - openIdx <= 1)
  74                                 throw new ArgumentException (expr + " is not a valid indexed expression.");
  75
  76                         string val = expr.Substring (openIdx + 1, closeIdx - openIdx - 1);
  77                         val = val.Trim ();
  78                         if (val.Length == 0)
  79                                 throw new ArgumentException (expr + " is not a valid indexed expression.");
  80
  81                         bool is_string = false;
  82                         // a quoted val means we have a string
  83                         if ((val[0] == '\'' && val[val.Length - 1] == '\'') ||
  84                                 (val[0] == '\"' && val[val.Length - 1] == '\"')) {
  85                                 is_string = true;
  86                                 val = val.Substring(1, val.Length - 2);
  87                         } else {
  88                                 // if all chars are digits, then we have a int
  89                                 for(int i = 0; i < val.Length; i++)
  90                                         if (!Char.IsDigit(val[i])) {
  91                                                 is_string = true;
  92                                                 break;
  93                                         }
  94                         }
  95
  96                         int intVal = 0;
  97                         if (!is_string) {
  98                                 try {
  99                                         intVal = Int32.Parse (val);
 100                                 } catch {
 101                                         throw new ArgumentException (expr + " is not a valid indexed expression.");
 102                                 }
 103                         }
 104
 105                         string property = null;
 106                         if (openIdx > 0) {
 107                                 property = expr.Substring (0, openIdx);
 108                                 if (property != null && property != String.Empty)
 109                                         container = GetPropertyValue (container, property);
 110                         }
 111
 112                         if (container == null)
 113                                 return null;
 114
 115                         if (container is System.Collections.IList) {
 116                                 IList l = (IList) container;
 117                                 return l [intVal];
 118                         }
 119
 120                         Type t = container.GetType ();
 121                         // MS does not seem to look for any other than "Item"!!!
 122                         object [] atts = t.GetCustomAttributes (typeof (DefaultMemberAttribute), false);
 123                         if (atts.Length != 1)
 124                                 throw new ArgumentException (expr + " indexer not found.");
 125
 126                         property = ((DefaultMemberAttribute) atts [0]).MemberName;
 127
 128                         Type [] argTypes = new Type [] { (is_string) ? typeof (string) : typeof (int) };
 129                         PropertyInfo prop = t.GetProperty (property, argTypes);
 130                         if (prop == null)
 131                                 throw new ArgumentException (expr + " indexer not found.");
 132
 133                         object [] args = new object [1];
 134                         if (is_string)
 135                                 args [0] = val;
 136                         else
 137                                 args [0] = intVal;
 138
 139                         return prop.GetValue (container, args);
 140                 }
 141
 142                 public static string GetIndexedPropertyValue (object container, string expr, string format)
 143                 {
 144                         object result = GetIndexedPropertyValue (container, expr);
 145                         return FormatResult (result, format);
 146                 }
 147
 148                 public static object GetPropertyValue (object container, string propName)
 149                 {
 150                         if (propName == null)
 151                                 throw new ArgumentNullException ("propName");
 152
 153                         PropertyDescriptor prop = TypeDescriptor.GetProperties (container).Find (propName, true);
 154                         if (prop == null) {
 155                                 throw new HttpException ("Property " + propName + " not found in " +
 156                                                          container.GetType ());
 157                         }
 158
 159                         return prop.GetValue (container);
 160                 }
 161
 162                 public static string GetPropertyValue (object container, string propName, string format)
 163                 {
 164                         object result = GetPropertyValue (container, propName);
 165                         return FormatResult (result, format);
 166                 }
 167
 168                 #if NET_1_2
 169                 public static object GetDataItem (object container, out bool foundDataItem)
 170                 {
 171                         foundDataItem = false;
 172                         if (container == null)
 173                                 return null;
 174
 175                         PropertyInfo pi = container.GetType ().GetProperty ("DataItem", BindingFlags.Public | BindingFlags.Instance);
 176                         if (pi == null)
 177                                 return null;
 178
 179                         foundDataItem = true;
 180                         return pi.GetValue (container, null);
 181                 }
 182
 183
 184                 public static object GetDataItem (object container)
 185                 {
 186                         bool flag;
 187                         return GetDataItem (container, out flag);
 188                 }
 189                 #endif
 190         }
 191 }
 192