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                         int valLength = val.Length;
  79                         if (valLength == 0)
  80                                 throw new ArgumentException (expr + " is not a valid indexed expression.");
  81
  82                         int intVal = 0;
  83                         bool is_string;
  84                         char first = val [0];
  85                         if (first >= '0' && first <= '9') {
  86                                 is_string = false;
  87                                 try {
  88                                         intVal = Int32.Parse (val);
  89                                 } catch {
  90                                         throw new ArgumentException (expr + " is not a valid indexed expression.");
  91                                 }
  92
  93                         } else if (first == '"' && val [valLength - 1] == '"') {
  94                                 is_string = true;
  95                                 val = val.Substring (0, val.Length - 1).Substring (1);
  96                         } else {
  97                                 throw new ArgumentException (expr + " is not a valid indexed expression.");
  98                         }
  99
 100                         string property = null;
 101                         if (openIdx > 0) {
 102                                 property = expr.Substring (0, openIdx);
 103                                 if (property != null && property != String.Empty)
 104                                         container = GetPropertyValue (container, property);
 105                         }
 106
 107                         if (container == null)
 108                                 return null;
 109
 110                         if (container is System.Collections.IList) {
 111                                 IList l = (IList) container;
 112                                 return l [intVal];
 113                         }
 114
 115                         Type t = container.GetType ();
 116                         // MS does not seem to look for any other than "Item"!!!
 117                         object [] atts = t.GetCustomAttributes (typeof (DefaultMemberAttribute), false);
 118                         if (atts.Length != 1)
 119                                 throw new ArgumentException (expr + " indexer not found.");
 120
 121                         property = ((DefaultMemberAttribute) atts [0]).MemberName;
 122
 123                         Type [] argTypes = new Type [] { (is_string) ? typeof (string) : typeof (int) };
 124                         PropertyInfo prop = t.GetProperty (property, argTypes);
 125                         if (prop == null)
 126                                 throw new ArgumentException (expr + " indexer not found.");
 127
 128                         object [] args = new object [1];
 129                         if (is_string)
 130                                 args [0] = val;
 131                         else
 132                                 args [0] = intVal;
 133
 134                         return prop.GetValue (container, args);
 135                 }
 136
 137                 public static string GetIndexedPropertyValue (object container, string expr, string format)
 138                 {
 139                         object result = GetIndexedPropertyValue (container, expr);
 140                         return FormatResult (result, format);
 141                 }
 142
 143                 public static object GetPropertyValue (object container, string propName)
 144                 {
 145                         if (propName == null)
 146                                 throw new ArgumentNullException ("propName");
 147
 148                         PropertyDescriptor prop = TypeDescriptor.GetProperties (container).Find (propName, true);
 149                         if (prop == null) {
 150                                 throw new HttpException ("Property " + propName + " not found in " +
 151                                                          container.GetType ());
 152                         }
 153
 154                         return prop.GetValue (container);
 155                 }
 156
 157                 public static string GetPropertyValue (object container, string propName, string format)
 158                 {
 159                         object result = GetPropertyValue (container, propName);
 160                         return FormatResult (result, format);
 161                 }
 162
 163                 #if NET_1_2
 164                 public static object GetDataItem (object container, out bool foundDataItem)
 165                 {
 166                         foundDataItem = false;
 167                         if (container == null)
 168                                 return null;
 169
 170                         PropertyInfo pi = container.GetType ().GetProperty ("DataItem", BindingFlags.Public | BindingFlags.Instance);
 171                         if (pi == null)
 172                                 return null;
 173
 174                         foundDataItem = true;
 175                         return pi.GetValue (container, null);
 176                 }
 177
 178
 179                 public static object GetDataItem (object container)
 180                 {
 181                         bool flag;
 182                         return GetDataItem (container, out flag);
 183                 }
 184                 #endif
 185         }
 186 }
 187