通过反射和返回类型查找方法 [英] Finding method through reflection and return type
问题描述
在进行了一些反射并设法从GetMethods中获取了一些数据之后，我终于碰壁了.我试图找到任何有关此消息的消息，但无济于事.
After having worked with reflection some and managed to get some data back from GetMethods I've finally hit a wall. I've tried to find any sources on this, but to no avail.
基本上，我正在ASP.NET(MVC webapi)中创建RESTFUL Api，并使用反射来查找包含数百个视图/存储过程的DataComponent类的正确方法.我已经克服了基本的障碍，但是现在当我终于尝试使用参数来查找特定的SQL视图时，我似乎遇到了错误:
Basically I'm creating a RESTFUL Api in ASP.NET (MVC webapi) and using reflection to find the correct method of a DataComponent class that contains hundreds of views / stored procedures. I've gotten past the basic hurdles, but now when I'm finally attempting to use a parameter to find a specific SQL-view I seem to be getting an error:
发现不明确的匹配项.
Ambiguous match found.
我认为这是因为我试图通过以下方式找到一个方法
I'm assuming this is because I'm attempting to find a single method through
MethodInfo theMethod = myType.GetMethod(toCheck);
但是结果是两种不同的方法.
据我的经理说，这是由于我们使用了两个不同的视图，这些视图返回了两个不同的DataType(一个是DataReader，另一个是DataSet).
According to my manager it's due to the fact that we are using two different views that return two different DataTypes (one a DataReader, the other a DataSet).
我想问的是 HIVEMIND 是如何通过手动检查返回的返回类型为DataSet或其他方式将这两个结果缩小到单个结果?
What I want to ask the HIVEMIND is how I can narrow down these two results to a single result either with the help of manually checking for the resulting returntype being DataSet or any other way?
后续问题:
我似乎无法将结果放入DataSet中，因为.Invoke方法需要一个 Object .我试图将返回值设置为Object，然后也将该对象转换为DataSet ...
I seem to be unable to put the results in a DataSet as the .Invoke method expects an Object. I've attempted to set the return to an Object and then casting the object to a DataSet too...
Type myType = (typeof(myClass));
MethodInfo[] arrayToCheck = myType.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);
Object result = new Object();
foreach (MethodInfo mi in arrayToCheck)
{
if (mi.Name.Equals(param) && mi.ReturnType == typeof(DataSet))
{
result = mi.Invoke(mi, arr);
}
}
DataSet ds = (DataSet)result; // Error here
其他信息:无法转换类型为'System.Object'的对象键入"System.Data.DataSet".
Additional information: Unable to cast object of type 'System.Object' to type 'System.Data.DataSet'.
问题继续:
试图实施答案提供的解决方案
Attempted to implement the solution provided by the answer
String[] arr = {"", conStr, ""};
var myType = (typeof(JaberoDC.JaberoDC.JaberoDC));
var method = myType.GetMethods(param, BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly).Single(mi => mi.ReturnType == typeof(DataSet));
var subject = Activator.CreateInstance(myType);
var result = method.Invoke(subject, arr);
DataSet ds = (DataSet)result;
但是，它似乎无法正常工作.
However, it doesn't seem to work as intended.
行
var method = myType.GetMethods (param, BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly) .Single(mi => mi.ReturnType == typeof(DataSet));
引发错误
未知的方法GetMethods(string，System.Reflection.BindingFlags)的System.Type
Unkown method GetMethods(string, System.Reflection.BindingFlags) of System.Type
还有
mi => mi.ReturnType == typeof(DataSet));
引发此错误:
变量mi的未知类型
Unkown type of variable mi
谢谢
推荐答案
对于您的后续问题，您需要创建一个调用该方法所用的特定类型的对象.对于具有默认(无参数)构造函数的类型，可以执行以下操作:
For your follow-up issue, you need to create an object of the specific type you're calling the method on. For types that have default (no-parameter) constructors, you can do this:
Object result = Activator.CreateInstance(myType);
因此您的总体代码可能如下所示:
So your overall code could look like this:
var myType = typeof(myClass);
var method = myType
.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)
.Single(mi => mi.Name == param && mi.ReturnType == typeof(DataSet));
var subject = Activator.CreateInstance(myType);
var result = method.Invoke(subject, arr);
Dataset ds = (DataSet)result ;
这篇关于通过反射和返回类型查找方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
