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FieldBuilder field = tb.DefineField ("length", typeof (int),
FieldAttributes.Private);
Creating a property or indexer requires a few more steps. First, call DefineProp
erty on a TypeBuilder, telling it the name and type of the property:
PropertyBuilder prop = tb.DefineProperty (
"Text", // Name of property
PropertyAttributes.None,
typeof (string), // Property type
new Type[0] // Indexer types
);
(If you’re writing an indexer, the final argument is an array of indexer types.) Note
that we haven’t specified the property visibility: this is done individually on the
accessor methods.
The next step is to write the get and set methods. By convention, their names
are csn3ed with “get_” or “set_”. You then attach them to the property by calling
SetGetMethod and SetSetMethod on the PropertyBuilder.
To give a complete example, we’ll take the following field and property declaration:
string _text;
public string Text
{
get { return _text; }
internal set { _text = value; }
}
and generate it dynamically:
FieldBuilder field = tb.DefineField ("_text", typeof (string),
FieldAttributes.Private);
PropertyBuilder prop = tb.DefineProperty (
"Text", // Name of property
PropertyAttributes.None,
typeof (string), // Property type
new Type[0]); // Indexer types
MethodBuilder getter = tb.DefineMethod (
"get_Text", // Method name
MethodAttributes.Public | MethodAttributes.SpecialName,
typeof (string), // Return type
new Type[0]); // Parameter types
ILGenerator getGen = getter.GetILGenerator();
getGen.Emit (OpCodes.Ldarg_0); // Load "this" onto eval stack
getGen.Emit (OpCodes.Ldfld, field); // Load field value onto eval stack
getGen.Emit (OpCodes.Ret); // Return
MethodBuilder setter = tb.DefineMethod (
"set_Text",
MethodAttributes.Assembly | MethodAttributes.SpecialName,
null, // Return type
new Type[] { typeof (string) } ); // Parameter types
720 | Chapter 18: Reflection and Metadata