Hi I am working in .net project.
I want to display the assembly information on the page.
User will enter the name of .net assembly in a textbox and then need to display information like all the properties, functions with parameters, constructors, destructor and inherited class names.
Please give some solution for this.
The solution is System.Reflection
using System.Reflection;
For loading assembly dynamically,use
Assembly asm=Assembly.LoadFile(#"Full path of .dll file");
Now to get all types in assembly,use
Type []alltypes=asm.GetTypes();
For information about methods, constructors,parameters,properties use
MethodInfo []GetMethods() ,ConstructorInfo []GetConstructors() ,ParameterInfo []GetParameter() ,PropertyInfo []GetProperty() etc and iterate.
And many more method are there,see the MSDN of System.Reflection
Related
I am currently using the following line of code in a web server control to get a reference to the loaded System.Web assembly:
var assembly = AppDomain.CurrentDomain.GetAssemblies()
.Single(i => i.FullName.Contains("System.Web,"));
I am a bit concerned that there could be an occasion where the Single method call fails because (1) the assembly can't be found, or (2) more than one assembly is returned. In the debugger, it looks like there is only one assembly that matches the selector (I've included the comma after System.Web as all of the others show as "System.Web.Whatever"), but this doesn't mean that the FullName of all assemblies loaded will never contain this text).
Is there a better way to identify the reference that I'm looking for so I know that it will always find it correctly?
Thanks.
The best way would be to use a type that you know is in the System.Web assembly, e.g.:
var assembly = typeof(System.Web.HttpContext).Assembly;
i have an microsoft .office.interop.excel(dll) located at an directory d:\abc. now i do not want to add them as an web reference in my projet and call them
rather call the dll dynamically from my code behind(.cs)
is ther any way we can do dynmically
anyhelp would be great
thank you
Yes, but you will need to use reflection because if you don't add the assembly as reference it won't be known at compile time. Take a look at LoadFrom method.
var assembly = Assembly.LoadFrom(#"d:\abc\microsoft.office.interop.excel.dll");
var someType = assembly.GetType("Namespace.Type");
var instance = Activator.CreateInstance(type);
someType.InvokeMember(... // the reflection pain goes on
Take a look in Assembly.Load() method.
I want to discourage you from doing that. It can definitely be done if read the dll into a byte[] and call AppDomain.CurrentDomain.Load(byte[]). However you will find that you can only work with the types of that assembly through reflection. Otherwise your code behind file will not compile. So if at all possible you should add a reference (not a web reference) to the dll.
In solution explorer of asp.net application we are adding something in References section
for eg:in our project there are sample.Dal,sample.exeption ,system.core etc
What is actually References means,,,can we add by 'using' statement
Using is used for namespace resolution. For example:
using System.Data;
lets you access the DataSet class without typing in the fully qualified name; System.Data.DataSet.
This doesn't however tell the compiler what assembly (DLL) the DataSet class lies in. So you need to tell it. So you refer to System.Data.dll by adding it to the references section in solution explorer.
A reference references assemblies required for the current project.
Where using statements reference namespaces for the current file.
And yes, a referenced namespace must exist in one of the referenced assemblies.
Yes, once you reference another project or assembly, it's namespaces and types are available for use in the project that references them (you must reference the project or assembly before you can use the types within it).
You can either use using declarations or fully-qualified type declarations to access the types, as in:
// Example1: The using keyword.
using System;
void Example1()
{
Int32 myExample;
// etc.
}
// Example2: Fully-qualified type.
void Example2()
{
System.Int32 myExample;
// etc.
}
Note: I have used C# here.
I have a class Customer in app_code folder in asp.net web site, how can I create an instance using reflection, for example using Activator.CreateInstance(assemblyName, typeName)? Because the app_code is dynamically compiled, I don't know the assembly in design time?
Thanks
Fred
The question is should be how get a full name of type in design time, I want to put it in web.config. I have ConfigSection type, it is in app_code folder, I need to declare it in configSection. Thanks
You should be able to use "App_Code" or "__Code" as the assembly name in the web.config
I think you can use Assembly.GetExecutingAssembly() to get a reference to the current assembly.
I have solved a similar problem in this way:
Type[] appCodeTypes = System.Reflection.Assembly.Load("App_Code").GetTypes();
You can also use GetType().Assembly if you know that it will be the same assembly as your currently executing code.
I have a generic Repository<T> class I want to use with an ObjectDataSource. Repository<T> lives in a separate project called DataAccess. According to this post from the MS newsgroups (relevant part copied below):
Internally, the ObjectDataSource is calling Type.GetType(string) to get the
type, so we need to follow the guideline documented in Type.GetType on how
to get type using generics. You can refer to MSDN Library on Type.GetType:
http://msdn2.microsoft.com/en-us/library/w3f99sx1.aspx
From the document, you will learn that you need to use backtick (`) to
denotes the type name which is using generics.
Also, here we must specify the assembly name in the type name string.
So, for your question, the answer is to use type name like follows:
TypeName="TestObjectDataSourceAssembly.MyDataHandler`1[System.String],TestObjectDataSourceAssembly"
Okay, makes sense. When I try it, however, the page throws an exception:
<asp:ObjectDataSource ID="MyDataSource" TypeName="MyProject.Repository`1[MyProject.MessageCategory],DataAccess" />
[InvalidOperationException: The type specified in the TypeName property of ObjectDataSource 'MyDataSource' could not be found.]
The curious thing is that this only happens when I'm viewing the page. When I open the "Configure Data Source" dialog from the VS2008 designer, it properly shows me the methods on my generic Repository class. Passing the TypeName string to Type.GetType() while debugging also returns a valid type. So what gives?
Do something like this.
Type type = typeof(Repository<MessageCategory);
string assemblyQualifiedName = type.AssemblyQualifiedName;
get the value of assemblyQualifiedName and paste it into the TypeName field. Note that Type.GetType(string), the value passed in must be
The assembly-qualified name of the type to get. See AssemblyQualifiedName. If the type is in the currently executing assembly or in Mscorlib.dll, it is sufficient to supply the type name qualified by its namespace.
So, it may work by passing in that string in your code, because that class is in the currently executing assembly (where you are calling it), where as the ObjectDataSource is not.
Most likely the type you are looking for is
MyProject.Repository`1[MyProject.MessageCategory, DataAccess, Version=1.0.0.0, Culture=neutral, PublicKey=null], DataAccess, Version=1.0.0.0, Culture=neutral, PublicKey=null
I know this is an old post but I have recently had this problem myself. Another solution would be to replace the inheritance with object composition, e.g.
[DataObject]
public class DataAccessObject {
private Repository<MessageCategory> _repository;
// ctor omitted for clarity
// ...
[DataObjectMethod(DataObjectMethodType.Select)]
public MessageCategory Get(int key) {
return _repository.Get(key);
}
}
This way the ObjectDataSource doesn't know about the repository because its hidden within the class. I have a class library in my facade layer that is a perfectly reasonable place to put this code in the project I am working on.
In addition, if you are using Resharper and interfaces, its possible to get Resharper to do the refactoring using Resharpers "Implement using field" function.
Darren,
Many, many thanks for your post. I've been fighting with this all day. Strangely, in my case, I need to double the square brackets, e.g. for your piece of code:
MyProject.Repository`1[[MyProject.MessageCategory, DataAccess, Version=1.0.0.0, Culture=neutral, PublicKey=null]], DataAccess, Version=1.0.0.0, Culture=neutral, PublicKey=null
Roger