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