I'm trying to call a generic method and need to pass it a Type dynamically. But get a compile error, 'CS0246: The type or namespace name `t' could not be found. Are you missing a using directive or an assembly reference'. Please tell me what I'm overlooking, thank you.
...in the main...
Type t = DiscoverType(field); // returns Type given FieldInfo via Type.GetType(string)
MethodInfo method = typeof(testClass).GetMethod("MyGenericMethod", BindingFlags.NonPublic | BindingFlags.Instance);
MethodInfo generic = method.MakeGenericMethod(typeof(t));
object[] args = {field};
generic.Invoke(this, args);
the generic method...
private void MyGenericMethod<T>(FieldInfo field)
{
field.SetValue(obj, new List<T>(objList));
}
Hard to know what exactly you are trying to do, but you can fix your compiler error like this:
MethodInfo generic = method.MakeGenericMethod(t);
You use the typeof operator to go from a type-name to a System.Type instance. In your case, you already have the System.Type instance you need so typeof isn't useful here.
Related
I have a method with this signature
public IEnumerable<T> GetAll<T>() where T : new()
{
// Orm Lite Version
return Connection.LoadSelect<T>();
}
At compile time I don't know the Type T. I only know the class name at runtime is it possible to call this method using reflection with something like this?
string TargetTBLName = ...;//TargetTBLName get's it's value at runtime
Type ParentTableClass = Type.GetType(TargetTBLName);
IEnumerable<Type.GetType(TargetTBLName)> test = Repository.GetAll<Type.GetType(TargetTBLName)>();
Any Ideas?
I'd give a Dynamitey library a go. You can do that in many different ways, but I prefer this one because of its simplicity. You can find it here.
var name = InvokeMemberName.Create;
var test = Dynamic.InvokeMember(Repository, name("GetAll", new[]{ParentTableClass }));
foreach(var obj in test)
{
obj.SomeMethodFromMyType();
}
Keep in mind, that if Repository is static, than you have to tweak it a bit to use static invocation context (look up the link).
Now you have a test object, which is a dynamic - you can use it with duck typing (which has some implications on speed, for example), but in general you can do whatever you want to do with a normal IEnumerable<YourType>.
If you want to use reflection:
MethodInfo getAll= typeof(Repository).GetMethod("GetAll");
MethodInfo getAllGeneric= getAll.MakeGenericMethod(ParentTableClass);
object result = getAllGeneric.Invoke(this, null);
//or null, null is Repository is static
var finalObject = result as IEnumerable;
Mind that since this ParentTableClass is an unknown during compilation, you won't have access to anything that the actual type provides - unless you use dynamic approach.
I am trying to add new overloaded constructor to an existing type.
I tried to do it with emit namespace, however created type doesnt inherit the base class and all other methods.
And after reading some articles, i decided its not possible with .net framework built-in classes.
So I got Mono.Cecil, but couldnt find any decent example how to achieve this.
I have encountered a sample which copies methods, but not props, fields etc.
This adds an empty constructor
void AddEmptyConstructor(TypeDefinition type, MethodReference baseEmptyConstructor)
{
var methodAttributes = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName;
var method = new MethodDefinition(".ctor", methodAttributes, ModuleDefinition.TypeSystem.Void);
method.Body.Instructions.Add(Instruction.Create(OpCodes.Ldarg_0));
method.Body.Instructions.Add(Instruction.Create(OpCodes.Call, baseEmptyConstructor));
method.Body.Instructions.Add(Instruction.Create(OpCodes.Ret));
type.Methods.Add(method);
}
You will need to extend it to pass through the extra parameters.
From here
I want to retrieve the private (implementation and other) methods of a class which implements an interface and also is derived from (inherits) a base class.
How can I achieve this using reflection?
Is there another way to achieve this?
This is what I'm trying to do. I need to view these private methods and their contents. I don't want to invoke them.
Dim assembly As System.Reflection.Assembly
Dim assemblyName As String assemblyName = System.IO.Path.GetFullPath("xyz.dll")
assembly = System.Reflection.Assembly.LoadFile(assemblyName)
assembly.GetType("myClass").Getmethods(Bindings.NonPublic)
assembly.GetType("myClass").GetMethods(BindingFlags.NonPublic) isn't working.
Making the assumption that you're trying to use the private methods of a 3rd party assembly:
I'd urge caution in using private methods, they have been made private for a reason and
might rely on some state that you won't be able to anticipate; Also, if the assembly gets updated in the future, the private behavior may be changed or removed causing you to have to re-write your code to compensate.
However, there are two methods at your disposal, if you want to continue.
One way us using the new Dynamic keyword in .net 4:
http://igoro.com/archive/use-c-dynamic-typing-to-conveniently-access-internals-of-an-object/
To use reflection, this question may help you:
How do I use reflection to invoke a private method?
Hope this helps.
BindingFlags
You must specify Instance or Static along with Public or NonPublic or no members will be returned.
Assembly myAssembly;
myAssembly = Assembly.LoadFrom(#"c:\xyz.dll");
Type myType = myAssembly.GetTypes()[0]; //change 0 according to your class type.
BindingFlags eFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
MethodInfo myMethod = myType.GetMethod("Methodname", eFlags);
object obj1 = myAssembly.CreateInstance(myType.FullName);
object obj2 = myMethod.Invoke(obj1, new object[2] { parameters1, parameters1 });
I would like to serialize the properties of the HttpBrowserCapibilities object so that it may be returned via a web method call. Currently the object cannot be serialized:
Cannot serialize member System.Web.Configuration.HttpCapabilitiesBase.Capabilities of type System.Collections.IDictionary, because it implements IDictionary.
...which is understandable. However, I would like to simply copy out the properties and their values to a hierarchy, i.e.
<HttpBrowserCapabilities>
<IsMobile>true</IsMobile>
</HttpBrowserCapabilities>
I'm starting to think I would need to use reflection to copy this object, but I haven't reached a conclusion. Does anyone have any suggestions to keep this simple?
Thanks,
George
Originally I posted an answer using XmlDocument, but I glossed over some of the web method stuff and didn't realize you were really trying to map a DTO.
Reflection sounds complicated but it really isn't. The following snippet will do what you want:
public static void Populate(object dest, IDictionary dictionary)
{
Type t = dest.GetType();
foreach (object key in dictionary)
{
PropertyInfo prop = t.GetProperty(key.ToString(),
BindingFlags.Instance | BindingFlags.Public);
if ((prop != null) && prop.CanWrite)
{
object value = dictionary[key];
prop.SetValue(dest, value, null);
}
}
}
Then invoke this as:
BrowserCapsDto dto = new BrowserCapsDto();
Populate(dto, Capabilities); // Capabilities is the real BrowserCaps
It's pretty easy because you already have an IDictionary and thus you already know all of the possible names you can map; you don't actually need to use any reflection on the source, just the destination.
How do you go about creating an instance of an object when given the class name as a string in an ASP.NET v2 application? For example, I've got a class called SystemLog defined in the app_code section of the application. The class is defined within the Reports namespace. To create an instance of the object, I do something like this:
Dim MyObject As New Global.Reports.SystemLog
However, I want to create this object using a string to define the type. The type name is stored in a SQL database as a string. I thinks it's probably something to do with Activator.CreateInstance(AssemblyName, TypeName) but what I don't know is what to pass in those strings. What is the assembly name of an ASP.NET web app?
Help!
Thanks, Rob.
PS. I don't want a hard coded Select statement :-)
string typeName = "Your Type Name Here";
Type t = Type.GetType(typeName);
object o = Activator.CreateInstance(t);
This will give you an instanciated type. If will be up to you to cast it to the correct type and call your appropriate methods.
If you need to create a type that doesn't have a parameterless constructor there is an overload on CreateInstance that takes a params of objects to pass to a constructor. More info at this MSDN article.
The following is able to create type, even if it's from another assembly:
public object CreateInstance(string typeName) {
var type = AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(a => a.GetTypes())
.FirstOrDefault(t => t.FullName == typeName);
return type.CreateInstance();
}
You can use this to get it from a particular assembly:
Assembly assembly = Assembly.Load("myAssembly");
Type ObjectType = assembly.GetType("Type name here");
then.....object o = Activator.CreateInstance(ObjectType);