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