这回答这个问题是由凯文在MEF discussion list提供。事实证明,可以使用以下代码片段从MEF ExportDefinition和ImportDefinition数据结构中提取所有必需的信息。
的第一步是将组件类型加载到目录。然后,对目录中的每个零件迭代导入和导出定义。导出定义只能放在类型,方法,属性和字段(我的代码目前忽略)上。所以要处理导出,可以使用下面的代码。
var exports = new List<Tuple<string, MemberInfo>>();
foreach (var export in part.ExportDefinitions)
{
var memberInfo = ReflectionModelServices.GetExportingMember(export);
Tuple<string, MemberInfo> exportDefinition = null;
switch (memberInfo.MemberType)
{
case MemberTypes.Method:
exportDefinition = new Tuple<string, MemberInfo>(export.ContractName, memberInfo.GetAccessors().First() as MethodInfo);
break;
case MemberTypes.NestedType:
case MemberTypes.TypeInfo:
exportDefinition = new Tuple<string, MemberInfo>(export.ContractName, memberInfo.GetAccessors().First() as Type);
break;
case MemberTypes.Property:
// this is a bit ugly because we assume that the underlying methods for a property are named as:
// get_PROPERTYNAME and set_PROPERTYNAME. In this case we assume that exports always
// have a get method.
var getMember = memberInfo.GetAccessors().Where(m => m.Name.Contains("get_")).First();
var name = getMember.Name.Substring("get_".Length);
var property = getMember.DeclaringType.GetProperty(name);
exportDefinition = new Tuple<string, MemberInfo>(export.ContractName, property);
break;
default:
throw new NotImplementedException();
}
exports.Add(exportDefinition);
}
为了处理的进口,这只能放置在性质,参数和字段(其再次忽略)以下代码可用于:
public void ExtractImports()
{
var imports = new List<Tuple<string, string>>();
foreach (var import in part.ImportDefinitions)
{
SerializedImportDefinition importDefinition = !ReflectionModelServices.IsImportingParameter(import)
? importDefinition = CreatePropertyImport(import)
: importDefinition = CreateConstructorParameterImport(import);
}
}
private Tuple<string, string> CreatePropertyImport(ImportDefinition import)
{
var memberInfo = ReflectionModelServices.GetImportingMember(import);
if (memberInfo.MemberType != MemberTypes.Property)
{
throw new ArgumentOutOfRangeException("import");
}
// this is a bit ugly because we assume that the underlying methods for a property are named as:
// get_PROPERTYNAME and set_PROPERTYNAME. In this case we assume that imports always
// have a set method.
var getMember = memberInfo.GetAccessors().Where(m => m.Name.Contains("set_")).First();
var name = getMember.Name.Substring("set_".Length);
var property = getMember.DeclaringType.GetProperty(name);
return new Tuple<string, string>(import.ContractName, property.ToString());
}
private Tuple<string, string> CreateConstructorParameterImport(ImportDefinition import)
{
var parameterInfo = ReflectionModelServices.GetImportingParameter(import);
return new Tuple<string, string>(import.ContractName, parameterInfo.Value.ToString());
}
注意,似乎导入不能通过方法参数提供,所以上面的代码不支持这些。
一旦所有的出口和进口都已经被处理是序列化存储MemberInfo对象转换成字符串格式的一个简单的问题。
非常好的工作。我前段时间正在寻找类似于我的一些问题中看到的类似内容,很快我会再次访问此功能。感谢分享并花时间回答你自己的问题。 –
'memberInfo'来自'memberInfo.GetAccessors()'哪里? – l33t
@ l33t我更新了代码示例以包含获取'memberInfo'对象的部分。我希望这更清楚。感谢您指出缺少的代码行。 – Petrik