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  • Mixing secure & unsecure channels

    - by user305023
    I am unable to use an unsecure channel once a secure channel has already been registered. The code below works only if on the client side, the unsecured channel is registered before. Is it possible to mix secure and unsecure channels without any constraint on the registration order ? using System; using System.Collections; using System.Runtime.Remoting; using System.Runtime.Remoting.Channels; using System.Runtime.Remoting.Channels.Tcp; public class SampleObject : MarshalByRefObject { public DateTime GetTest() { return DateTime.Now; } } public class SampleObject2 : MarshalByRefObject { public DateTime GetTest2() { return DateTime.Now; } } static class ProgramClient { private static TcpClientChannel RegisterChannel(bool secure, string name, int priority) { IDictionary properties = new Hashtable(); properties.Add("secure", secure); properties.Add("name", name); properties.Add("priority", priority); var clientChannel = new TcpClientChannel(properties, null); ChannelServices.RegisterChannel(clientChannel, false); return clientChannel; } private static void Secure() { RegisterChannel(true, "clientSecure", 2); var testSecure = (SampleObject2)Activator.GetObject(typeof(SampleObject2), "tcp://127.0.0.1:8081/Secured.rem"); Console.WriteLine("secure: " + testSecure.GetTest2().ToLongTimeString()); } private static void Unsecure() { RegisterChannel(false, "clientUnsecure", 1); var test = (SampleObject)Activator.GetObject(typeof(SampleObject), "tcp://127.0.0.1:8080/Unsecured.rem"); Console.WriteLine("unsecure: " + test.GetTest().ToLongTimeString()); } internal static void MainClient() { Console.Write("Press Enter to start."); Console.ReadLine(); // Works only in this order Unsecure(); Secure(); Console.WriteLine("Press ENTER to end"); Console.ReadLine(); } } static class ProgramServer { private static TcpServerChannel RegisterChannel(int port, bool secure, string name) { IDictionary properties = new Hashtable(); properties.Add("port", port); properties.Add("secure", secure); properties.Add("name", name); //properties.Add("impersonate", false); var serverChannel = new TcpServerChannel(properties, null); ChannelServices.RegisterChannel(serverChannel, secure); return serverChannel; } private static void StartUnsecure() { RegisterChannel(8080, false, "unsecure"); RemotingConfiguration.RegisterWellKnownServiceType(typeof(SampleObject), "Unsecured.rem", WellKnownObjectMode.Singleton); } private static void StartSecure() { RegisterChannel(8081, true, "secure"); RemotingConfiguration.RegisterWellKnownServiceType(typeof(SampleObject2), "Secured.rem", WellKnownObjectMode.Singleton); } internal static void MainServer() { StartUnsecure(); StartSecure(); Console.WriteLine("Unsecure: 8080\n Secure: 8081"); Console.WriteLine("Press the enter key to exit..."); Console.ReadLine(); } } class Program { static void Main(string[] args) { if (args.Length == 1 && args[0] == "server") ProgramServer.MainServer(); else ProgramClient.MainClient(); } }

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  • [.NET Remoting] Mixing secure & unsecure channels

    - by user305023
    I am unable to use an unsecure channel once a secure channel has already been registered. The code below works only if on the client side, the unsecured channel is registered before. Is it possible to mix secure and unsecure channels without any contraints on the registration order ? using System; using System.Collections; using System.Runtime.Remoting; using System.Runtime.Remoting.Channels; using System.Runtime.Remoting.Channels.Tcp; public class SampleObject : MarshalByRefObject { public DateTime GetTest() { return DateTime.Now; } } public class SampleObject2 : MarshalByRefObject { public DateTime GetTest2() { return DateTime.Now; } } static class ProgramClient { private static TcpClientChannel RegisterChannel(bool secure, string name, int priority) { IDictionary properties = new Hashtable(); properties.Add("secure", secure); properties.Add("name", name); properties.Add("priority", priority); var clientChannel = new TcpClientChannel(properties, null); ChannelServices.RegisterChannel(clientChannel, false); return clientChannel; } private static void Secure() { RegisterChannel(true, "clientSecure", 2); var testSecure = (SampleObject2)Activator.GetObject(typeof(SampleObject2), "tcp://127.0.0.1:8081/Secured.rem"); Console.WriteLine("secure: " + testSecure.GetTest2().ToLongTimeString()); } private static void Unsecure() { RegisterChannel(false, "clientUnsecure", 1); var test = (SampleObject)Activator.GetObject(typeof(SampleObject), "tcp://127.0.0.1:8080/Unsecured.rem"); Console.WriteLine("unsecure: " + test.GetTest().ToLongTimeString()); } internal static void MainClient() { Console.Write("Press Enter to start."); Console.ReadLine(); // Works only in this order Unsecure(); Secure(); Console.WriteLine("Press ENTER to end"); Console.ReadLine(); } } static class ProgramServer { private static TcpServerChannel RegisterChannel(int port, bool secure, string name) { IDictionary properties = new Hashtable(); properties.Add("port", port); properties.Add("secure", secure); properties.Add("name", name); //properties.Add("impersonate", false); var serverChannel = new TcpServerChannel(properties, null); ChannelServices.RegisterChannel(serverChannel, secure); return serverChannel; } private static void StartUnsecure() { RegisterChannel(8080, false, "unsecure"); RemotingConfiguration.RegisterWellKnownServiceType(typeof(SampleObject), "Unsecured.rem", WellKnownObjectMode.Singleton); } private static void StartSecure() { RegisterChannel(8081, true, "secure"); RemotingConfiguration.RegisterWellKnownServiceType(typeof(SampleObject2), "Secured.rem", WellKnownObjectMode.Singleton); } internal static void MainServer() { StartUnsecure(); StartSecure(); Console.WriteLine("Unsecure: 8080\n Secure: 8081"); Console.WriteLine("Press the enter key to exit..."); Console.ReadLine(); } } class Program { static void Main(string[] args) { if (args.Length == 1 && args[0] == "server") ProgramServer.MainServer(); else ProgramClient.MainClient(); } }

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  • Typesafe fire-and-forget asynchronous delegate invocation in C#

    - by LBushkin
    I recently found myself needing a typesafe "fire-and-forget" mechanism for running code asynchronously. Ideally, what I would want to do is something like: var myAction = (Action)(() => Console.WriteLine("yada yada")); myAction.FireAndForget(); // async invocation Unfortunately, the obvious choice of calling BeginInvoke() without a corresponding EndInvoke() does not work - it results in a slow resource leak (since the asyn state is held by the runtime and never released ... it's expecting an eventual call to EndInvoke(). I also can't run the code on the .NET thread pool because it may take a very long time to complete (it's advised to only run relatively short-lived code on the thread pool) - this makes it impossible to use the ThreadPool.QueueUserWorkItem(). Initially, I only needed this behavior for methods whose signature matches Action, Action<...>, or Func<...>. So I put together a set of extension methods (see listing below) that let me do this without running into the resource leak. There are overloads for each version of Action/Func. Unfortunately, I now want to port this code to .NET 4 where the number of generic parameters on Action and Func have been increased substantially. Before I write a T4 script to generate these, I was also hoping to find a simpler more elegant way to do this. Any ideas are welcome. public static class AsyncExt { public static void FireAndForget( this Action action ) { action.BeginInvoke(OnActionCompleted, action); } public static void FireAndForget<T1>( this Action<T1> action, T1 arg1 ) { action.BeginInvoke(arg1, OnActionCompleted<T1>, action); } public static void FireAndForget<T1,T2>( this Action<T1,T2> action, T1 arg1, T2 arg2 ) { action.BeginInvoke(arg1, arg2, OnActionCompleted<T1, T2>, action); } public static void FireAndForget<TResult>(this Func<TResult> func, TResult arg1) { func.BeginInvoke(OnFuncCompleted<TResult>, func); } public static void FireAndForget<T1,TResult>(this Func<T1, TResult> action, T1 arg1) { action.BeginInvoke(arg1, OnFuncCompleted<T1,TResult>, action); } // more overloads of FireAndForget<..>() for Action<..> and Func<..> private static void OnActionCompleted( IAsyncResult result ) { var action = (Action)result.AsyncState; action.EndInvoke(result); } private static void OnActionCompleted<T1>( IAsyncResult result ) { var action = (Action<T1>)result.AsyncState; action.EndInvoke( result ); } private static void OnActionCompleted<T1,T2>(IAsyncResult result) { var action = (Action<T1,T2>)result.AsyncState; action.EndInvoke(result); } private static void OnFuncCompleted<TResult>( IAsyncResult result ) { var func = (Func<TResult>)result.AsyncState; func.EndInvoke( result ); } private static void OnFuncCompleted<T1,TResult>(IAsyncResult result) { var func = (Func<T1, TResult>)result.AsyncState; func.EndInvoke(result); } // more overloads of OnActionCompleted<> and OnFuncCompleted<> }

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  • BadPaddingException in Android encrypt

    - by DarthRoman
    Hi everyone, I am making an Android application, and I want to encrypt a String before sending it to a DataBase, and encrytpion is correct. The problem is when I am going to decrypt the String, because I get a BadPaddingException and I have no idea where the problem is. Here is the code: public final static String HEX = "36A52C8FB7DF9A3F"; public static String encrypt(String seed, String cleartext) throws Exception { byte[] rawKey = getRawKey(seed.getBytes()); byte[] result = encrypt(rawKey, cleartext.getBytes()); return toHex(result); } public static String decrypt(String seed, String encrypted) throws Exception { byte[] rawKey = getRawKey(seed.getBytes()); byte[] enc = toByte(encrypted); byte[] result = decrypt(rawKey, enc); return new String(result); } public static String toHex(String txt) { return toHex(txt.getBytes()); } public static String fromHex(String hex) { return new String(toByte(hex)); } public static byte[] toByte(String hexString) { int len = hexString.length()/2; byte[] result = new byte[len]; for (int i = 0; i < len; i++) result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue(); return result; } public static String toHex(byte[] buf) { if (buf == null) return ""; StringBuffer result = new StringBuffer(2*buf.length); for (int i = 0; i < buf.length; i++) { appendHex(result, buf[i]); } return result.toString(); } private static byte[] getRawKey(byte[] seed) throws Exception { KeyGenerator kgen = KeyGenerator.getInstance("AES"); SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"); sr.setSeed(seed); kgen.init(128, sr); // 192 and 256 bits may not be available SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); return raw; } private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); byte[] encrypted = cipher.doFinal(clear); return encrypted; } private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] decrypted = cipher.doFinal(encrypted); return decrypted; } private static void appendHex(StringBuffer sb, byte b) { sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f)); } I encrypt and decrypt with this code: String encrypted = encrypt(HEX, "some text"); String decrypted = decrypt(HEX, encrypted); Can anyone help me please? Thank you very much!!

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  • Sqlite returns error

    - by ruruma
    I'm trying to implement loading data from database and put it into different views. But log cat returns error, that it cannot find "_id" column. Can somebody help me with this? SqlHelper Code public class FiboSqlHelper extends SQLiteOpenHelper { public static final String TABLE_FILMDB = "FiboFilmTop250"; public static final String COLUMN_ID = "_id"; private static final String DATABASE_NAME = "FiboFilmDb250.sqlite"; private static final int DATABASE_VERSION = 1; public static final String COLUMN_TITLE = "Title"; public static final String COLUMN_RATING = "Rating"; public static final String COLUMN_GENRE = "Genre"; public static final String COLUMN_TIME = "Time"; public static final String COLUMN_PREMDATE = "PremDate"; public static final String COLUMN_PLOT = "Plot"; private static final String DATABASE_CREATE = "create table "+TABLE_FILMDB+"("+COLUMN_ID +" integer primary key autoincrement, " +COLUMN_TITLE+" text not null "+COLUMN_RATING+" text not null "+COLUMN_GENRE+" text not null "+COLUMN_TIME+" text not null "+COLUMN_PREMDATE+" text not null "+COLUMN_PLOT+" "+"text not null)"; public FiboSqlHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub Log.w(FiboSqlHelper.class.getName(), "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS " + TABLE_FILMDB); onCreate(db); } }` SqlAdapterCode: public class FiboSqlAdapter { private SQLiteDatabase database; private FiboSqlHelper dbHelper; private String[] allColumns = {FiboSqlHelper.COLUMN_ID, FiboSqlHelper.COLUMN_TITLE, FiboSqlHelper.COLUMN_GENRE, FiboSqlHelper.COLUMN_PREMDATE, FiboSqlHelper.COLUMN_TIME, FiboSqlHelper.COLUMN_PLOT}; public FiboSqlAdapter (Context context){ dbHelper = new FiboSqlHelper(context); } public void open() throws SQLException { database = dbHelper.getWritableDatabase(); } public void close(){ dbHelper.close(); } public List<FilmDataEntity> getAllFilmData(){ List<FilmDataEntity> fDatas = new ArrayList<FilmDataEntity>(); Cursor cursor = database.query(FiboSqlHelper.TABLE_FILMDB, allColumns, null,null,null,null,null); cursor.moveToFirst(); while(!cursor.isAfterLast()){ FilmDataEntity fData = cursorToData(cursor); fDatas.add(fData); cursor.moveToNext(); } cursor.close(); return fDatas; } private FilmDataEntity cursorToData(Cursor cursor){ FilmDataEntity fData = new FilmDataEntity(); fData.setId(cursor.getLong(1)); fData.setTitle(cursor.getString(2)); fData.setRating(cursor.getString(6)); fData.setGenre(cursor.getString(4)); fData.setPremDate(cursor.getString(5)); fData.setShortcut(cursor.getString(8)); return fData; }} DataEntity: ` public class FilmDataEntity { private long id; private String title; private String rating; private String genre; private String premDate; private String shortcut; public String getShortcut() { return shortcut; } public void setShortcut(String shortcut) { this.shortcut = shortcut; } public String getGenre() { return genre; } public void setGenre(String genre) { this.genre = genre; } public String getPremDate() { return premDate; } public void setPremDate(String premDate) { this.premDate = premDate; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getRating() { return rating; } public void setRating(String rating) { this.rating = rating; } public long getId() { return id; } public void setId(long id) { this.id = id; } } Part from main activity: `List<FilmDataEntity> fE1; sqA = new FiboSqlAdapter(this); sqA.open(); fE1 = sqA.getAllFilmData(); `

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  • How to properly add .NET assemblies to Powershell session?

    - by amandion
    I have a .NET assembly (a dll) which is an API to backup software we use here. It contains some properties and methods I would like to take advantage of in my Powershell script(s). However, I am running into a lot of issues with first loading the assembly, then using any of the types once the assembly is loaded. The complete file path is: C:\rnd\CloudBerry.Backup.API.dll In Powershell I use: $dllpath = "C:\rnd\CloudBerry.Backup.API.dll" Add-Type -Path $dllpath I get the error below: Add-Type : Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information. At line:1 char:9 + Add-Type <<<< -Path $dllpath + CategoryInfo : NotSpecified: (:) [Add-Type], ReflectionTypeLoadException + FullyQualifiedErrorId : System.Reflection.ReflectionTypeLoadException,Microsoft.PowerShell.Commands.AddTypeComma ndAdd-Type : Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information. Using the same cmdlet on another .NET assembly, DotNetZip, which has examples of using the same functionality on the site also does not work for me. I eventually find that I am seemingly able to load the assembly using reflection: [System.Reflection.Assembly]::LoadFrom($dllpath) Although I don't understand the difference between the methods Load, LoadFrom, or LoadFile that last method seems to work. However, I still seem to be unable to create instances or use objects. Each time I try, I get errors that describe that Powershell is unable to find any of the public types. I know the classes are there: $asm = [System.Reflection.Assembly]::LoadFrom($dllpath) $cbbtypes = $asm.GetExportedTypes() $cbbtypes | Get-Member -Static ---- start of excerpt ---- TypeName: CloudBerryLab.Backup.API.BackupProvider Name MemberType Definition ---- ---------- ---------- PlanChanged Event System.EventHandler`1[CloudBerryLab.Backup.API.Utils.ChangedEventArgs] PlanChanged(Sy... PlanRemoved Event System.EventHandler`1[CloudBerryLab.Backup.API.Utils.PlanRemoveEventArgs] PlanRemoved... CalculateFolderSize Method static long CalculateFolderSize() Equals Method static bool Equals(System.Object objA, System.Object objB) GetAccounts Method static CloudBerryLab.Backup.API.Account[], CloudBerry.Backup.API, Version=1.0.0.1, Cu... GetBackupPlans Method static CloudBerryLab.Backup.API.BackupPlan[], CloudBerry.Backup.API, Version=1.0.0.1,... ReferenceEquals Method static bool ReferenceEquals(System.Object objA, System.Object objB) SetProfilePath Method static System.Void SetProfilePath(string profilePath) ----end of excerpt---- Trying to use static methods fail, I don't know why!!! [CloudBerryLab.Backup.API.BackupProvider]::GetAccounts() Unable to find type [CloudBerryLab.Backup.API.BackupProvider]: make sure that the assembly containing this type is load ed. At line:1 char:42 + [CloudBerryLab.Backup.API.BackupProvider] <<<< ::GetAccounts() + CategoryInfo : InvalidOperation: (CloudBerryLab.Backup.API.BackupProvider:String) [], RuntimeException + FullyQualifiedErrorId : TypeNotFound Any guidance appreciated!!

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  • VirtualBox 4.1.12 Ubuntu Host Bridged Networking

    - by hidden_premise
    Setup Ubuntu Server 11.10 x64 VirtualBox 4.1.12 One network adapter eth0 with a static IP address My /etc/network/interfaces looks like #Local loopback auto lo iface lo inet loopback #Primary Interface auto eth0 iface eth0 inet static address 10.0.0.6 netmask 255.255.255.0 gateway 10.0.0.1 Need Static IP for Ubuntu Host Static IP for multiple Ubuntu guests My attempt Downloaded the .deb for 64bit virtual box dpkg -i virtualbox.deb Create a VM and install ubuntu server 11.10 x64 from ISO Set the networking mode to bridged and choose 'eth0' as the interface Fail. None of the guides I can find for bridged networking work because everything changed since vbox 2

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  • How to configure a hostname of sub-application?

    - by BrunoLM
    I have a structure like this: Website |- Controllers |- Models |- Views |- Content |- Static (APP) Website is an application using an ASP.NET 4.0 pool. Static is a sub-application using a not managed application pool. On Website bindings I've set local.domain.com to have access through port 80. I want to access the Static app using static.domain.com, but I don't find the option to configure the binding. How is it possible to configure like that?

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  • Creating a dynamic, extensible C# Expando Object

    - by Rick Strahl
    I love dynamic functionality in a strongly typed language because it offers us the best of both worlds. In C# (or any of the main .NET languages) we now have the dynamic type that provides a host of dynamic features for the static C# language. One place where I've found dynamic to be incredibly useful is in building extensible types or types that expose traditionally non-object data (like dictionaries) in easier to use and more readable syntax. I wrote about a couple of these for accessing old school ADO.NET DataRows and DataReaders more easily for example. These classes are dynamic wrappers that provide easier syntax and auto-type conversions which greatly simplifies code clutter and increases clarity in existing code. ExpandoObject in .NET 4.0 Another great use case for dynamic objects is the ability to create extensible objects - objects that start out with a set of static members and then can add additional properties and even methods dynamically. The .NET 4.0 framework actually includes an ExpandoObject class which provides a very dynamic object that allows you to add properties and methods on the fly and then access them again. For example with ExpandoObject you can do stuff like this:dynamic expand = new ExpandoObject(); expand.Name = "Rick"; expand.HelloWorld = (Func<string, string>) ((string name) => { return "Hello " + name; }); Console.WriteLine(expand.Name); Console.WriteLine(expand.HelloWorld("Dufus")); Internally ExpandoObject uses a Dictionary like structure and interface to store properties and methods and then allows you to add and access properties and methods easily. As cool as ExpandoObject is it has a few shortcomings too: It's a sealed type so you can't use it as a base class It only works off 'properties' in the internal Dictionary - you can't expose existing type data It doesn't serialize to XML or with DataContractSerializer/DataContractJsonSerializer Expando - A truly extensible Object ExpandoObject is nice if you just need a dynamic container for a dictionary like structure. However, if you want to build an extensible object that starts out with a set of strongly typed properties and then allows you to extend it, ExpandoObject does not work because it's a sealed class that can't be inherited. I started thinking about this very scenario for one of my applications I'm building for a customer. In this system we are connecting to various different user stores. Each user store has the same basic requirements for username, password, name etc. But then each store also has a number of extended properties that is available to each application. In the real world scenario the data is loaded from the database in a data reader and the known properties are assigned from the known fields in the database. All unknown fields are then 'added' to the expando object dynamically. In the past I've done this very thing with a separate property - Properties - just like I do for this class. But the property and dictionary syntax is not ideal and tedious to work with. I started thinking about how to represent these extra property structures. One way certainly would be to add a Dictionary, or an ExpandoObject to hold all those extra properties. But wouldn't it be nice if the application could actually extend an existing object that looks something like this as you can with the Expando object:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } } and then simply start extending the properties of this object dynamically? Using the Expando object I describe later you can now do the following:[TestMethod] public void UserExampleTest() { var user = new User(); // Set strongly typed properties user.Email = "[email protected]"; user.Password = "nonya123"; user.Name = "Rickochet"; user.Active = true; // Now add dynamic properties dynamic duser = user; duser.Entered = DateTime.Now; duser.Accesses = 1; // you can also add dynamic props via indexer user["NickName"] = "AntiSocialX"; duser["WebSite"] = "http://www.west-wind.com/weblog"; // Access strong type through dynamic ref Assert.AreEqual(user.Name,duser.Name); // Access strong type through indexer Assert.AreEqual(user.Password,user["Password"]); // access dyanmically added value through indexer Assert.AreEqual(duser.Entered,user["Entered"]); // access index added value through dynamic Assert.AreEqual(user["NickName"],duser.NickName); // loop through all properties dynamic AND strong type properties (true) foreach (var prop in user.GetProperties(true)) { object val = prop.Value; if (val == null) val = "null"; Console.WriteLine(prop.Key + ": " + val.ToString()); } } As you can see this code somewhat blurs the line between a static and dynamic type. You start with a strongly typed object that has a fixed set of properties. You can then cast the object to dynamic (as I discussed in my last post) and add additional properties to the object. You can also use an indexer to add dynamic properties to the object. To access the strongly typed properties you can use either the strongly typed instance, the indexer or the dynamic cast of the object. Personally I think it's kinda cool to have an easy way to access strongly typed properties by string which can make some data scenarios much easier. To access the 'dynamically added' properties you can use either the indexer on the strongly typed object, or property syntax on the dynamic cast. Using the dynamic type allows all three modes to work on both strongly typed and dynamic properties. Finally you can iterate over all properties, both dynamic and strongly typed if you chose. Lots of flexibility. Note also that by default the Expando object works against the (this) instance meaning it extends the current object. You can also pass in a separate instance to the constructor in which case that object will be used to iterate over to find properties rather than this. Using this approach provides some really interesting functionality when use the dynamic type. To use this we have to add an explicit constructor to the Expando subclass:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } public User() : base() { } // only required if you want to mix in seperate instance public User(object instance) : base(instance) { } } to allow the instance to be passed. When you do you can now do:[TestMethod] public void ExpandoMixinTest() { // have Expando work on Addresses var user = new User( new Address() ); // cast to dynamicAccessToPropertyTest dynamic duser = user; // Set strongly typed properties duser.Email = "[email protected]"; user.Password = "nonya123"; // Set properties on address object duser.Address = "32 Kaiea"; //duser.Phone = "808-123-2131"; // set dynamic properties duser.NonExistantProperty = "This works too"; // shows default value Address.Phone value Console.WriteLine(duser.Phone); } Using the dynamic cast in this case allows you to access *three* different 'objects': The strong type properties, the dynamically added properties in the dictionary and the properties of the instance passed in! Effectively this gives you a way to simulate multiple inheritance (which is scary - so be very careful with this, but you can do it). How Expando works Behind the scenes Expando is a DynamicObject subclass as I discussed in my last post. By implementing a few of DynamicObject's methods you can basically create a type that can trap 'property missing' and 'method missing' operations. When you access a non-existant property a known method is fired that our code can intercept and provide a value for. Internally Expando uses a custom dictionary implementation to hold the dynamic properties you might add to your expandable object. Let's look at code first. The code for the Expando type is straight forward and given what it provides relatively short. Here it is.using System; using System.Collections.Generic; using System.Linq; using System.Dynamic; using System.Reflection; namespace Westwind.Utilities.Dynamic { /// <summary> /// Class that provides extensible properties and methods. This /// dynamic object stores 'extra' properties in a dictionary or /// checks the actual properties of the instance. /// /// This means you can subclass this expando and retrieve either /// native properties or properties from values in the dictionary. /// /// This type allows you three ways to access its properties: /// /// Directly: any explicitly declared properties are accessible /// Dynamic: dynamic cast allows access to dictionary and native properties/methods /// Dictionary: Any of the extended properties are accessible via IDictionary interface /// </summary> [Serializable] public class Expando : DynamicObject, IDynamicMetaObjectProvider { /// <summary> /// Instance of object passed in /// </summary> object Instance; /// <summary> /// Cached type of the instance /// </summary> Type InstanceType; PropertyInfo[] InstancePropertyInfo { get { if (_InstancePropertyInfo == null && Instance != null) _InstancePropertyInfo = Instance.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly); return _InstancePropertyInfo; } } PropertyInfo[] _InstancePropertyInfo; /// <summary> /// String Dictionary that contains the extra dynamic values /// stored on this object/instance /// </summary> /// <remarks>Using PropertyBag to support XML Serialization of the dictionary</remarks> public PropertyBag Properties = new PropertyBag(); //public Dictionary<string,object> Properties = new Dictionary<string, object>(); /// <summary> /// This constructor just works off the internal dictionary and any /// public properties of this object. /// /// Note you can subclass Expando. /// </summary> public Expando() { Initialize(this); } /// <summary> /// Allows passing in an existing instance variable to 'extend'. /// </summary> /// <remarks> /// You can pass in null here if you don't want to /// check native properties and only check the Dictionary! /// </remarks> /// <param name="instance"></param> public Expando(object instance) { Initialize(instance); } protected virtual void Initialize(object instance) { Instance = instance; if (instance != null) InstanceType = instance.GetType(); } /// <summary> /// Try to retrieve a member by name first from instance properties /// followed by the collection entries. /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; // first check the Properties collection for member if (Properties.Keys.Contains(binder.Name)) { result = Properties[binder.Name]; return true; } // Next check for Public properties via Reflection if (Instance != null) { try { return GetProperty(Instance, binder.Name, out result); } catch { } } // failed to retrieve a property result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { // first check to see if there's a native property to set if (Instance != null) { try { bool result = SetProperty(Instance, binder.Name, value); if (result) return true; } catch { } } // no match - set or add to dictionary Properties[binder.Name] = value; return true; } /// <summary> /// Dynamic invocation method. Currently allows only for Reflection based /// operation (no ability to add methods dynamically). /// </summary> /// <param name="binder"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (Instance != null) { try { // check instance passed in for methods to invoke if (InvokeMethod(Instance, binder.Name, args, out result)) return true; } catch { } } result = null; return false; } /// <summary> /// Reflection Helper method to retrieve a property /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="result"></param> /// <returns></returns> protected bool GetProperty(object instance, string name, out object result) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { result = ((PropertyInfo)mi).GetValue(instance,null); return true; } } result = null; return false; } /// <summary> /// Reflection helper method to set a property value /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="value"></param> /// <returns></returns> protected bool SetProperty(object instance, string name, object value) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { ((PropertyInfo)mi).SetValue(Instance, value, null); return true; } } return false; } /// <summary> /// Reflection helper method to invoke a method /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> protected bool InvokeMethod(object instance, string name, object[] args, out object result) { if (instance == null) instance = this; // Look at the instanceType var miArray = InstanceType.GetMember(name, BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0] as MethodInfo; result = mi.Invoke(Instance, args); return true; } result = null; return false; } /// <summary> /// Convenience method that provides a string Indexer /// to the Properties collection AND the strongly typed /// properties of the object by name. /// /// // dynamic /// exp["Address"] = "112 nowhere lane"; /// // strong /// var name = exp["StronglyTypedProperty"] as string; /// </summary> /// <remarks> /// The getter checks the Properties dictionary first /// then looks in PropertyInfo for properties. /// The setter checks the instance properties before /// checking the Properties dictionary. /// </remarks> /// <param name="key"></param> /// /// <returns></returns> public object this[string key] { get { try { // try to get from properties collection first return Properties[key]; } catch (KeyNotFoundException ex) { // try reflection on instanceType object result = null; if (GetProperty(Instance, key, out result)) return result; // nope doesn't exist throw; } } set { if (Properties.ContainsKey(key)) { Properties[key] = value; return; } // check instance for existance of type first var miArray = InstanceType.GetMember(key, BindingFlags.Public | BindingFlags.GetProperty); if (miArray != null && miArray.Length > 0) SetProperty(Instance, key, value); else Properties[key] = value; } } /// <summary> /// Returns and the properties of /// </summary> /// <param name="includeProperties"></param> /// <returns></returns> public IEnumerable<KeyValuePair<string,object>> GetProperties(bool includeInstanceProperties = false) { if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) yield return new KeyValuePair<string, object>(prop.Name, prop.GetValue(Instance, null)); } foreach (var key in this.Properties.Keys) yield return new KeyValuePair<string, object>(key, this.Properties[key]); } /// <summary> /// Checks whether a property exists in the Property collection /// or as a property on the instance /// </summary> /// <param name="item"></param> /// <returns></returns> public bool Contains(KeyValuePair<string, object> item, bool includeInstanceProperties = false) { bool res = Properties.ContainsKey(item.Key); if (res) return true; if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) { if (prop.Name == item.Key) return true; } } return false; } } } Although the Expando class supports an indexer, it doesn't actually implement IDictionary or even IEnumerable. It only provides the indexer and Contains() and GetProperties() methods, that work against the Properties dictionary AND the internal instance. The reason for not implementing IDictionary is that a) it doesn't add much value since you can access the Properties dictionary directly and that b) I wanted to keep the interface to class very lean so that it can serve as an entity type if desired. Implementing these IDictionary (or even IEnumerable) causes LINQ extension methods to pop up on the type which obscures the property interface and would only confuse the purpose of the type. IDictionary and IEnumerable are also problematic for XML and JSON Serialization - the XML Serializer doesn't serialize IDictionary<string,object>, nor does the DataContractSerializer. The JavaScriptSerializer does serialize, but it treats the entire object like a dictionary and doesn't serialize the strongly typed properties of the type, only the dictionary values which is also not desirable. Hence the decision to stick with only implementing the indexer to support the user["CustomProperty"] functionality and leaving iteration functions to the publicly exposed Properties dictionary. Note that the Dictionary used here is a custom PropertyBag class I created to allow for serialization to work. One important aspect for my apps is that whatever custom properties get added they have to be accessible to AJAX clients since the particular app I'm working on is a SIngle Page Web app where most of the Web access is through JSON AJAX calls. PropertyBag can serialize to XML and one way serialize to JSON using the JavaScript serializer (not the DCS serializers though). The key components that make Expando work in this code are the Properties Dictionary and the TryGetMember() and TrySetMember() methods. The Properties collection is public so if you choose you can explicitly access the collection to get better performance or to manipulate the members in internal code (like loading up dynamic values form a database). Notice that TryGetMember() and TrySetMember() both work against the dictionary AND the internal instance to retrieve and set properties. This means that user["Name"] works against native properties of the object as does user["Name"] = "RogaDugDog". What's your Use Case? This is still an early prototype but I've plugged it into one of my customer's applications and so far it's working very well. The key features for me were the ability to easily extend the type with values coming from a database and exposing those values in a nice and easy to use manner. I'm also finding that using this type of object for ViewModels works very well to add custom properties to view models. I suspect there will be lots of uses for this - I've been using the extra dictionary approach to extensibility for years - using a dynamic type to make the syntax cleaner is just a bonus here. What can you think of to use this for? Resources Source Code and Tests (GitHub) Also integrated in Westwind.Utilities of the West Wind Web Toolkit West Wind Utilities NuGet© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET  Dynamic Types   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Django CMS - not able to upload images through cmsplugin_filer_image

    - by Luke
    i have a problem with a local installation on django cms 2.3.3: i've installed it trough pip, in a separated virtualenv. next i followed the tutorial for settings.py configuration, i started the server. Then in the admin i created an page (home), and i've tried to add an image in the placeholder through the cmsplugin_filer_image, but the upload seems that doesn't work. here's my settings.py: # Django settings for cms1 project. # -*- coding: utf-8 -*- import os gettext = lambda s: s PROJECT_PATH = os.path.abspath(os.path.dirname(__file__)) DEBUG = True TEMPLATE_DEBUG = DEBUG ADMINS = ( # ('Your Name', '[email protected]'), ) MANAGERS = ADMINS DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'. 'NAME': 'cms1', # Or path to database file if using sqlite3. 'USER': 'cms', # Not used with sqlite3. 'PASSWORD': 'cms', # Not used with sqlite3. 'HOST': '', # Set to empty string for localhost. Not used with sqlite3. 'PORT': '', # Set to empty string for default. Not used with sqlite3. } } # Local time zone for this installation. Choices can be found here: # http://en.wikipedia.org/wiki/List_of_tz_zones_by_name # although not all choices may be available on all operating systems. # In a Windows environment this must be set to your system time zone. TIME_ZONE = 'Europe/Rome' # Language code for this installation. All choices can be found here: # http://www.i18nguy.com/unicode/language-identifiers.html LANGUAGE_CODE = 'it-it' SITE_ID = 1 # If you set this to False, Django will make some optimizations so as not # to load the internationalization machinery. USE_I18N = True # If you set this to False, Django will not format dates, numbers and # calendars according to the current locale. USE_L10N = True # If you set this to False, Django will not use timezone-aware datetimes. USE_TZ = True # Absolute filesystem path to the directory that will hold user-uploaded files. # Example: "/home/media/media.lawrence.com/media/" MEDIA_ROOT = os.path.join(PROJECT_PATH, "media") # URL that handles the media served from MEDIA_ROOT. Make sure to use a # trailing slash. # Examples: "http://media.lawrence.com/media/", "http://example.com/media/" MEDIA_URL = '/media/' # Absolute path to the directory static files should be collected to. # Don't put anything in this directory yourself; store your static files # in apps' "static/" subdirectories and in STATICFILES_DIRS. # Example: "/home/media/media.lawrence.com/static/" STATIC_ROOT = os.path.join(PROJECT_PATH, "static") STATIC_URL = "/static/" # Additional locations of static files STATICFILES_DIRS = ( os.path.join(PROJECT_PATH, "static_auto"), # Put strings here, like "/home/html/static" or "C:/www/django/static". # Always use forward slashes, even on Windows. # Don't forget to use absolute paths, not relative paths. ) # List of finder classes that know how to find static files in # various locations. STATICFILES_FINDERS = ( 'django.contrib.staticfiles.finders.FileSystemFinder', 'django.contrib.staticfiles.finders.AppDirectoriesFinder', # 'django.contrib.staticfiles.finders.DefaultStorageFinder', ) # Make this unique, and don't share it with anybody. SECRET_KEY = '^c2q3d8w)f#gk%5i)(#i*lwt%lm-!2=(*1d!1cf+rg&amp;-hqi_9u' # List of callables that know how to import templates from various sources. TEMPLATE_LOADERS = ( 'django.template.loaders.filesystem.Loader', 'django.template.loaders.app_directories.Loader', # 'django.template.loaders.eggs.Loader', ) MIDDLEWARE_CLASSES = ( 'django.middleware.common.CommonMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'cms.middleware.multilingual.MultilingualURLMiddleware', 'cms.middleware.page.CurrentPageMiddleware', 'cms.middleware.user.CurrentUserMiddleware', 'cms.middleware.toolbar.ToolbarMiddleware', # Uncomment the next line for simple clickjacking protection: # 'django.middleware.clickjacking.XFrameOptionsMiddleware', ) ROOT_URLCONF = 'cms1.urls' # Python dotted path to the WSGI application used by Django's runserver. WSGI_APPLICATION = 'cms1.wsgi.application' TEMPLATE_DIRS = ( os.path.join(PROJECT_PATH, "templates"), # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates". # Always use forward slashes, even on Windows. # Don't forget to use absolute paths, not relative paths. ) CMS_TEMPLATES = ( ('template_1.html', 'Template One'), ('template_2.html', 'Template Two'), ) TEMPLATE_CONTEXT_PROCESSORS = ( 'django.contrib.auth.context_processors.auth', 'django.core.context_processors.i18n', 'django.core.context_processors.request', 'django.core.context_processors.media', 'django.core.context_processors.static', 'cms.context_processors.media', 'sekizai.context_processors.sekizai', ) LANGUAGES = [ ('it', 'Italiano'), ('en', 'English'), ] INSTALLED_APPS = ( 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.staticfiles', 'cms', #django CMS itself 'mptt', #utilities for implementing a modified pre-order traversal tree 'menus', #helper for model independent hierarchical website navigation 'south', #intelligent schema and data migrations 'sekizai', #for javascript and css management #'cms.plugins.file', 'cms.plugins.flash', 'cms.plugins.googlemap', 'cms.plugins.link', #'cms.plugins.picture', 'cms.plugins.snippet', 'cms.plugins.teaser', 'cms.plugins.text', #'cms.plugins.video', 'cms.plugins.twitter', 'filer', 'cmsplugin_filer_file', 'cmsplugin_filer_folder', 'cmsplugin_filer_image', 'cmsplugin_filer_teaser', 'cmsplugin_filer_video', 'easy_thumbnails', 'PIL', # Uncomment the next line to enable the admin: 'django.contrib.admin', # Uncomment the next line to enable admin documentation: # 'django.contrib.admindocs', ) # A sample logging configuration. The only tangible logging # performed by this configuration is to send an email to # the site admins on every HTTP 500 error when DEBUG=False. # See http://docs.djangoproject.com/en/dev/topics/logging for # more details on how to customize your logging configuration. LOGGING = { 'version': 1, 'disable_existing_loggers': False, 'filters': { 'require_debug_false': { '()': 'django.utils.log.RequireDebugFalse' } }, 'handlers': { 'mail_admins': { 'level': 'ERROR', 'filters': ['require_debug_false'], 'class': 'django.utils.log.AdminEmailHandler' } }, 'loggers': { 'django.request': { 'handlers': ['mail_admins'], 'level': 'ERROR', 'propagate': True, }, } } when i try to upload an image, in the clipboard section i don't have the thumbnail, but just an 'undefined' message: and this is the runserver console while trying to upload: [20/Oct/2012 15:15:56] "POST /admin/filer/clipboard/operations/upload/?qqfile=29708_1306856312320_7706073_n.jpg HTTP/1.1" 500 248133 [20/Oct/2012 15:15:56] "GET /it/admin/filer/folder/unfiled_images/undefined HTTP/1.1" 301 0 [20/Oct/2012 15:15:56] "GET /it/admin/filer/folder/unfiled_images/undefined/ HTTP/1.1" 404 1739 Also, this is project filesystem: cms1 +-- cms1 ¦   +-- __init__.py ¦   +-- __init__.pyc ¦   +-- media ¦   ¦   +-- filer_public ¦   ¦   +-- 2012 ¦   ¦   +-- 10 ¦   ¦   +-- 20 ¦   ¦   +-- 29708_1306856312320_7706073_n_1.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_2.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_3.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_4.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_5.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_6.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n_7.jpg ¦   ¦   +-- 29708_1306856312320_7706073_n.jpg ¦   ¦   +-- torrent-client-macosx.jpg ¦   +-- settings.py ¦   +-- settings.pyc ¦   +-- static ¦   +-- static_auto ¦   +-- static_manual ¦   +-- templates ¦   ¦   +-- base.html ¦   ¦   +-- template_1.html ¦   ¦   +-- template_2.html ¦   +-- urls.py ¦   +-- urls.pyc ¦   +-- wsgi.py ¦   +-- wsgi.pyc +-- manage.py So files are uploaded, but they are not accessible to cms. there's a similar question here, but doens't help me so much. It would be very helpful any help on this issue to me. Thanks, luke

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  • CheckBox Command Behaviors for Silverlight MVVM Pattern

    - by Blake Blackwell
    I am trying to detect when an item is checked, and which item is checked in a ListBox using Silverlight 4 and the Prism framework. I found this example on creating behaviors, and tried to follow it but nothing is happening in the debugger. I have three questions: Why isn't my command executing? How do I determine which item was checked (i.e. pass a command parameter)? How do I debug this? (i.e. where can I put break points to begin stepping into this) Here is my code: View: <ListBox x:Name="MyListBox" ItemsSource="{Binding PanelItems, Mode=TwoWay}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <CheckBox IsChecked="{Binding Enabled}" my:Checked.Command="{Binding Check}" /> <TextBlock x:Name="DisplayName" Text="{Binding DisplayName}"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> ViewModel: public MainPageViewModel() { _panelItems.Add( new PanelItem { Enabled = true, DisplayName = "Test1" } ); Check = new DelegateCommand<object>( itemChecked ); } public void itemChecked( object o ) { //do some stuff } public DelegateCommand<object> Check { get; set; } Behavior Class public class CheckedBehavior : CommandBehaviorBase<CheckBox> { public CheckedBehavior( CheckBox element ) : base( element ) { element.Checked +=new RoutedEventHandler(element_Checked); } void element_Checked( object sender, RoutedEventArgs e ) { base.ExecuteCommand(); } } Command Class public static class Checked { public static ICommand GetCommand( DependencyObject obj ) { return (ICommand) obj.GetValue( CommandProperty ); } public static void SetCommand( DependencyObject obj, ICommand value ) { obj.SetValue( CommandProperty, value ); } public static readonly DependencyProperty CommandProperty = DependencyProperty.RegisterAttached( "Command", typeof( CheckBox ), typeof( Checked ), new PropertyMetadata( OnSetCommandCallback ) ); public static readonly DependencyProperty CheckedCommandBehaviorProperty = DependencyProperty.RegisterAttached( "CheckedCommandBehavior", typeof( CheckedBehavior ), typeof( Checked ), null ); private static void OnSetCommandCallback( DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e ) { CheckBox element = dependencyObject as CheckBox; if( element != null ) { CheckedBehavior behavior = GetOrCreateBehavior( element ); behavior.Command = e.NewValue as ICommand; } } private static CheckedBehavior GetOrCreateBehavior( CheckBox element ) { CheckedBehavior behavior = element.GetValue( CheckedCommandBehaviorProperty ) as CheckedBehavior; if( behavior == null ) { behavior = new CheckedBehavior( element ); element.SetValue( CheckedCommandBehaviorProperty, behavior ); } return behavior; } public static CheckedBehavior GetCheckCommandBehavior( DependencyObject obj ) { return (CheckedBehavior) obj.GetValue( CheckedCommandBehaviorProperty ); } public static void SetCheckCommandBehavior( DependencyObject obj, CheckedBehavior value ) { obj.SetValue( CheckedCommandBehaviorProperty, value ); } } I used this article to get me started, but I'll readily admit this is over my head.

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  • Camera Preview App in Android throwing many errors (Nexus 4)

    - by Jagatheesan Jack
    I am trying to develop a camera app that takes a picture and saves it in a SQLite database. I get a lot of errors when executing the application. My code is as below. Any idea? CameraActivity.java private Camera mCamera; private CameraPreview mPreview; private int CAMERA_RETURN_CODE=100; private static final String TAG = "Take_Picture"; public static final int MEDIA_TYPE_IMAGE = 1; public static final int MEDIA_TYPE_VIDEO = 2; private Bitmap cameraBmp; private int MAX_FACES = 1; private Face[] faceList; public RectF[] rects; private Canvas canvas; private Drawable pictureDataDrawable; private MySQLiteHelper database; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.camera_activity); //this.requestWindowFeature(Window.FEATURE_NO_TITLE); //Create an instance of Camera mCamera = getCameraInstance(); setCameraDisplayOrientation(this, 0, mCamera); // Create our Preview view and set it as the content of our activity. mPreview = new CameraPreview(this, mCamera); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mPreview); database = new MySQLiteHelper(getApplicationContext()); Button captureButton = (Button) findViewById(R.id.button_capture); captureButton.setOnClickListener( new View.OnClickListener() { private PictureCallback mPicture; @Override public void onClick(View v) { //mCamera.startPreview(); // get an image from the camera mCamera.takePicture(null, null, mPicture); PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { try{ if (data != null) database.addEntry(data); //mCamera.startPreview(); } catch(Exception e){ Log.d(TAG, e.getMessage()); } } } ); } /** A safe way to get an instance of the Camera object. */ public static Camera getCameraInstance(){ Camera c = null; try { c = Camera.open(c.getNumberOfCameras()-1); // attempt to get a Camera instance } catch (Exception e){ // Camera is not available (in use or does not exist) } return c; // returns null if camera is unavailable } public static void setCameraDisplayOrientation(Activity activity, int cameraId, android.hardware.Camera camera) { android.hardware.Camera.CameraInfo info = new android.hardware.Camera.CameraInfo(); android.hardware.Camera.getCameraInfo(cameraId, info); int rotation = activity.getWindowManager().getDefaultDisplay() .getRotation(); int degrees = 360; /*switch (rotation) { case Surface.ROTATION_0: degrees = 0; break; case Surface.ROTATION_90: degrees = 90; break; case Surface.ROTATION_180: degrees = 180; break; case Surface.ROTATION_270: degrees = 270; break; }*/ int result; if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) { result = (info.orientation + degrees) % 360; result = (360 - result) % 360; // compensate the mirror } else { // back-facing result = (info.orientation - degrees + 360) % 360; } camera.setDisplayOrientation(result); } @Override protected void onPause() { super.onPause(); //releaseMediaRecorder(); // if you are using MediaRecorder, release it first releaseCamera(); // release the camera immediately on pause event } private void releaseCamera(){ if (mCamera != null){ mCamera.release(); // release the camera for other applications mCamera = null; } } public void startFaceDetection(){ // Try starting Face Detection Camera.Parameters params = mCamera.getParameters(); // start face detection only *after* preview has started if (params.getMaxNumDetectedFaces() > 0){ // camera supports face detection, so can start it: mCamera.startFaceDetection(); } } CameraPreview.java public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback { private SurfaceHolder mHolder; private Camera mCamera; private String TAG; private List<Size> mSupportedPreviewSizes; public CameraPreview(Context context, Camera camera) { super(context); mCamera = camera; // Install a SurfaceHolder.Callback so we get notified when the // underlying surface is created and destroyed. mHolder = getHolder(); mHolder.addCallback(this); // deprecated setting, but required on Android versions prior to 3.0 mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } public void surfaceCreated(SurfaceHolder holder) { // The Surface has been created, now tell the camera where to draw the preview. try { mCamera.setPreviewDisplay(holder); mCamera.setDisplayOrientation(90); mCamera.startPreview(); } catch (IOException e) { Log.d(TAG, "Error setting camera preview: " + e.getMessage()); } } public void surfaceDestroyed(SurfaceHolder holder) { // empty. Take care of releasing the Camera preview in your activity. } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { // If your preview can change or rotate, take care of those events here. // Make sure to stop the preview before resizing or reformatting it. if (mHolder.getSurface() == null){ // preview surface does not exist return; } // stop preview before making changes try { mCamera.stopPreview(); } catch (Exception e){ // ignore: tried to stop a non-existent preview } try { mCamera.setPreviewDisplay(mHolder); mCamera.startPreview(); } catch (Exception e){ Log.d(TAG, "Error starting camera preview: " + e.getMessage()); } } public void setCamera(Camera camera) { if (mCamera == camera) { return; } mCamera = camera; if (mCamera != null) { List<Size> localSizes = mCamera.getParameters().getSupportedPreviewSizes(); mSupportedPreviewSizes = localSizes; requestLayout(); try { mCamera.setPreviewDisplay(mHolder); } catch (IOException e) { e.printStackTrace(); } /* Important: Call startPreview() to start updating the preview surface. Preview must be started before you can take a picture. */ mCamera.startPreview(); } } MySQLiteHelper.java private static final int count = 0; public static final String TABLE_IMAGE = "images"; public static final String COLUMN_ID = "_id"; public static final String PICTURE_DATA = "picture"; public static final String DATABASE_NAME = "images.db"; public static final int DATABASE_VERSION = 1; public static final String DATABASE_CREATE = "create table " + TABLE_IMAGE + "(" + COLUMN_ID + " integer primary key autoincrement, " + PICTURE_DATA + " blob not null);"; public static SQLiteDatabase database; private static String TAG = "test"; public MySQLiteHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); // TODO Auto-generated constructor stub } public MySQLiteHelper(Context context, String name, CursorFactory factory, int version, DatabaseErrorHandler errorHandler) { super(context, name, factory, version, errorHandler); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase database) { database.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w(MySQLiteHelper.class.getName(), "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS " + TABLE_IMAGE); onCreate(db); } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub } public void addEntry(byte [] array) throws SQLiteException{ ContentValues cv = new ContentValues(); //cv.put(KEY_NAME, name); cv.put(PICTURE_DATA, array); database.insert( TABLE_IMAGE, null, cv ); Log.w(TAG , "added " +count+ "images"); database.close(); } Errors 11-07 23:28:39.050: E/mm-libcamera2(176): PROFILE HAL: stopPreview(): E: 1383838119.067589459 11-07 23:28:39.050: E/mm-camera(201): config_MSG_ID_STOP_ACK: streamon_mask is not clear. Should not call PP_Release_HW 11-07 23:28:39.090: E/QCameraHWI(176): android::status_t android::QCameraHardwareInterface::setPreviewWindow(preview_stream_ops_t*):Received Setting NULL preview window 11-07 23:28:39.090: E/QCameraHWI(176): android::status_t android::QCameraHardwareInterface::setPreviewWindow(preview_stream_ops_t*): mPreviewWindow = 0x0x0, mStreamDisplay = 0x0xb8a9df90 11-07 23:28:39.090: E/mm-camera(201): config_shutdown_pp Camera not in streaming mode. Returning. 11-07 23:28:39.090: E/mm-camera(201): vfe_ops_deinit: E 11-07 23:28:39.120: E/qcom_sensors_hal(533): hal_process_report_ind: Bad item quality: 11 11-07 23:28:39.310: E/qcom_sensors_hal(533): hal_process_report_ind: Bad item quality: 11 11-07 23:28:39.330: E/mm-camera(201): sensor_load_chromatix: libchromatix_imx119_preview.so: 30 11-07 23:28:39.340: E/mm-camera(201): vfe_ops_init: E 11-07 23:28:39.360: E/mm-camera(201): vfe_legacy_stats_buffer_init: AEC_STATS_BUFNUM 11-07 23:28:39.360: E/mm-camera(201): vfe_legacy_stats_buffer_init: AEC_STATS_BUFNUM 11-07 23:28:39.360: E/mm-camera(201): mctl_init_stats_proc_info: snap_max_line_cnt =25776 11-07 23:28:39.440: E/QCameraHWI(176): android::status_t android::QCameraHardwareInterface::setPreviewWindow(preview_stream_ops_t*): mPreviewWindow = 0x0xb8aa1780, mStreamDisplay = 0x0xb8a9df90 11-07 23:28:39.440: E/mm-camera(201): config_proc_CAMERA_SET_INFORM_STARTPREVIEW 11-07 23:28:39.450: E/mm-camera(201): config_update_stream_info Storing stream parameters for video inst 1 as : width = 640, height 480, format = 1 inst_handle = 810081 cid = 0 11-07 23:28:39.490: E/mm-camera(201): config_update_stream_info Storing stream parameters for video inst 3 as : width = 640, height 480, format = 1 inst_handle = 830083 cid = 0 11-07 23:28:39.490: E/mm-camera(201): config_update_stream_info Storing stream parameters for video inst 4 as : width = 512, height 384, format = 1 inst_handle = 840084 cid = 0 11-07 23:28:39.500: E/mm-camera(201): config_decide_vfe_outputs: Ports Used 3, Op mode 1 11-07 23:28:39.500: E/mm-camera(201): config_decide_vfe_outputs Current mode 0 Full size streaming : Disabled 11-07 23:28:39.500: E/mm-camera(201): config_decide_vfe_outputs: Primary: 640x480, extra_pad: 0x0, Fmt: 1, Type: 1, Path: 1 11-07 23:28:39.500: E/mm-camera(201): config_decide_vfe_outputs: Secondary: 640x480, extra_pad: 0x0, Fmt: 1, Type: 3, Path: 4 11-07 23:28:39.510: E/mm-camera(201): config_update_inst_handles Updated the inst handles as 810081, 830083, 0, 0 11-07 23:28:39.631: E/mm-camera(201): sensor_load_chromatix: libchromatix_imx119_preview.so: 30 11-07 23:28:39.631: E/mm-camera(201): camif_client_set_params: camif has associated with obj mask 0x1 11-07 23:28:39.631: E/mm-camera(201): config_v2_CAMERA_START_common CAMIF_PARAMS_ADD_OBJ_ID failed -1 11-07 23:28:39.641: E/mm-camera(201): vfe_operation_config: format 3 11-07 23:28:39.641: E/mm-camera(201): vfe_operation_config:vfe_op_mode=5 11-07 23:28:39.641: E/mm-camera(201): Invalid ASD Set Params Type 11-07 23:28:39.641: E/mm-camera(201): vfe_set_bestshot: Bestshot mode not changed

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  • Android never receives UDP packet

    - by Quandary
    The below code results in a timeout. It works fine on non-Android Java. What's the matter? //@Override public static void run() { //System.out.println ( "Local Machine IP : "+addrStr.toString ( ) ) ; HelloWorldActivity.tv.setText("Trace 1"); try { // Retrieve the ServerName InetAddress serverAddr; //= InetAddress.getByName(Server.SERVERIP); InetAddress ias[] = InetAddress.getAllByName(Server.SERVERNAME); serverAddr = ias[0]; Log.d("UDP", "C: Connecting..."); /* Create new UDP-Socket */ DatagramSocket socket = new DatagramSocket(); /* Prepare some data to be sent. */ String strQuery="ÿÿÿÿgetservers"+" "+Server.iProtocol+" "+"'all'"; Log.d("UDP", strQuery); //byte[] buf = ("ÿÿÿÿgetservers 68 'all'").getBytes(); byte[] buf = strQuery.getBytes(); /* Create UDP-packet with * data & destination(url+port) */ DatagramPacket packet = new DatagramPacket(buf, buf.length, serverAddr, Server.SERVERPORT); Log.d("UDP", "C: Sending: '" + new String(buf) + "'"); /* Send out the packet */ socket.setSoTimeout(5000); socket.send(packet); Log.d("UDP", "C: Sent."); Log.d("UDP", "C: Done."); // http://code.google.com/p/android/issues/detail?id=2917 byte[] buffer= new byte[1024*100]; DatagramPacket receivePacket = new DatagramPacket(buffer, buffer.length); //, serverAddr, Server.SERVERPORT); socket.receive(receivePacket); HelloWorldActivity.tv.setText("TTT"); String x = new String(receivePacket.getData()); Log.d("UDP", "C: Received: '" + x + "'"); HelloWorldActivity.tv.setText(x); } catch (Exception e) { HelloWorldActivity.tv.setText(e.getMessage()); Log.e("UDP", "C: Error", e); } } public class Server { /* //public static java.lang.string SERVERIP; public static String SERVERNAME = "monster.idsoftware.com"; public static String SERVERIP = "192.246.40.56"; public static int SERVERPORT = 27950; public static int PROTOCOL = 68; */ //public static String SERVERNAME="monster.idsoftware.com"; public static String SERVERNAME="dpmaster.deathmask.net"; public static String SERVERIP="192.246.40.56"; public static int SERVERPORT=27950; //public static int iProtocol= 68; // Quake3 public static int iProtocol=71; // OpenArena } Android manifest: <?xml version="1.0" encoding="utf-8"?> <use-permission id="android.permission.READ_CONTACTS" /> <use-permission android:name="android.permission.WRITE_SETTINGS" /> <uses-permission android:name="android.permission.READ_CONTACTS" /> <uses-permission android:name="android.permission.CALL_PHONE" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_GPS" /> <uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.ACCESS_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_ASSISTED_GPS" /> <uses-permission android:name="android.permission.ACCESS_CELL_ID" /> <uses-permission android:name="android.permission.RECEIVE_SMS" /> <uses-permission android:name="android.permission.VIBRATE" /> <uses-permission android:name="android.permission.WAKE_LOCK" /> <application android:icon="@drawable/icon" android:label="AAA New Application" > <activity android:name="HelloWorldActivity"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application>

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  • Singleton by Jon Skeet clarification

    - by amutha
    public sealed class Singleton { Singleton() { } public static Singleton Instance { get { return Nested.instance; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly Singleton instance = new Singleton(); } } I wish to implement Jon Skeet's Singleton pattern in my current application in C#. I have two doubts on the code 1) How is it possible to access the outer class inside nested class? I mean internal static readonly Singleton instance = new Singleton(); Is something called closure? 2) I did not get this comment // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit what does this comment suggest us?

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  • threaded serial port IOException when writing

    - by John McDonald
    Hi, I'm trying to write a small application that simply reads data from a socket, extracts some information (two integers) from the data and sends the extracted information off on a serial port. The idea is that it should start and just keep going. In short, it works, but not for long. After a consistently short period I start to receive IOExceptions and socket receive buffer is swamped. The thread framework has been taken from the MSDN serial port example. The delay in send(), readThread.Join(), is an effort to delay read() in order to allow serial port interrupt processing a chance to occur, but I think I've misinterpreted the join function. I either need to sync the processes more effectively or throw some data away as it comes in off the socket, which would be fine. The integer data is controlling a pan tilt unit and I'm sure four times a second would be acceptable, but not sure on how to best acheive either, any ideas would be greatly appreciated, cheers. using System; using System.Collections.Generic; using System.Text; using System.IO.Ports; using System.Threading; using System.Net; using System.Net.Sockets; using System.IO; namespace ConsoleApplication1 { class Program { static bool _continue; static SerialPort _serialPort; static Thread readThread; static Thread sendThread; static String sendString; static Socket s; static int byteCount; static Byte[] bytesReceived; // synchronise send and receive threads static bool dataReceived; const int FIONREAD = 0x4004667F; static void Main(string[] args) { dataReceived = false; readThread = new Thread(Read); sendThread = new Thread(Send); bytesReceived = new Byte[16384]; // Create a new SerialPort object with default settings. _serialPort = new SerialPort("COM4", 38400, Parity.None, 8, StopBits.One); // Set the read/write timeouts _serialPort.WriteTimeout = 500; _serialPort.Open(); string moveMode = "CV "; _serialPort.WriteLine(moveMode); s = null; IPHostEntry hostEntry = Dns.GetHostEntry("localhost"); foreach (IPAddress address in hostEntry.AddressList) { IPEndPoint ipe = new IPEndPoint(address, 10001); Socket tempSocket = new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp); tempSocket.Connect(ipe); if (tempSocket.Connected) { s = tempSocket; s.ReceiveBufferSize = 16384; break; } else { continue; } } readThread.Start(); sendThread.Start(); while (_continue) { Thread.Sleep(10); ;// Console.WriteLine("main..."); } readThread.Join(); _serialPort.Close(); s.Close(); } public static void Read() { while (_continue) { try { //Console.WriteLine("Read"); if (!dataReceived) { byte[] outValue = BitConverter.GetBytes(0); // Check how many bytes have been received. s.IOControl(FIONREAD, null, outValue); uint bytesAvailable = BitConverter.ToUInt32(outValue, 0); if (bytesAvailable > 0) { Console.WriteLine("Read thread..." + bytesAvailable); byteCount = s.Receive(bytesReceived); string str = Encoding.ASCII.GetString(bytesReceived); //str = Encoding::UTF8->GetString( bytesReceived ); string[] split = str.Split(new Char[] { '\t', '\r', '\n' }); string filteredX = (split.GetValue(7)).ToString(); string filteredY = (split.GetValue(8)).ToString(); string[] AzSplit = filteredX.Split(new Char[] { '.' }); filteredX = (AzSplit.GetValue(0)).ToString(); string[] ElSplit = filteredY.Split(new Char[] { '.' }); filteredY = (ElSplit.GetValue(0)).ToString(); // scale values int x = (int)(Convert.ToInt32(filteredX) * 1.9); string scaledAz = x.ToString(); int y = (int)(Convert.ToInt32(filteredY) * 1.9); string scaledEl = y.ToString(); String moveAz = "PS" + scaledAz + " "; String moveEl = "TS" + scaledEl + " "; sendString = moveAz + moveEl; dataReceived = true; } } } catch (TimeoutException) {Console.WriteLine("timeout exception");} catch (NullReferenceException) {Console.WriteLine("Read NULL reference exception");} } } public static void Send() { while (_continue) { try { if (dataReceived) { // sleep Read() thread to allow serial port interrupt processing readThread.Join(100); // send command to PTU dataReceived = false; Console.WriteLine(sendString); _serialPort.WriteLine(sendString); } } catch (TimeoutException) { Console.WriteLine("Timeout exception"); } catch (IOException) { Console.WriteLine("IOException exception"); } catch (NullReferenceException) { Console.WriteLine("Send NULL reference exception"); } } } } }

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  • How can I implement an abstract singleton class in Java?

    - by Simon
    Here is my sample abstract singleton class: public abstract class A { protected static A instance; public static A getInstance() { return instance; } //...rest of my abstract methods... } And here is the concrete implementation: public class B extends A { private B() { } static { instance = new B(); } //...implementations of my abstract methods... } Unfortunately I can't get the static code in class B to execute, so the instance variable never gets set. I have tried this: Class c = B.class; A.getInstance() - returns null; and this ClassLoader.getSystemClassLoader().loadClass("B"); A.getInstance() - return null; Running both these in the eclipse debugger the static code never gets executed. The only way I could find to get the static code executed is to change the accessibility on B's constructor to public, and to call it. I'm using sun-java6-jre on Ubuntu 32bit to run these tests.

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  • Rendering HTML in Java

    - by ferronrsmith
    I am trying to create a help panel for an application I am working on. The help file as already been created using html technology and I would like it to be rendered in a pane and shown. All the code I have seen shows how to render a site e.g. "http://google.com". I want to render a file from my pc e.g. "file://c:\tutorial.html" This is the code i have, but it doesn't seem to be working. import javax.swing.JEditorPane; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JScrollPane; import javax.swing.SwingUtilities; import java.awt.Color; import java.awt.Container; import java.io.IOException; import static java.lang.System.err; import static java.lang.System.out; final class TestHTMLRendering { // ------------------------------ CONSTANTS ------------------------------ /** * height of frame in pixels */ private static final int height = 1000; /** * width of frame in pixels */ private static final int width = 1000; private static final String RELEASE_DATE = "2007-10-04"; /** * title for frame */ private static final String TITLE_STRING = "HTML Rendering"; /** * URL of page we want to display */ private static final String URL = "file://C:\\print.html"; /** * program version */ private static final String VERSION_STRING = "1.0"; // --------------------------- main() method --------------------------- /** * Debugging harness for a JFrame * * @param args command line arguments are ignored. */ @SuppressWarnings( { "UnusedParameters" } ) public static void main( String args[] ) { // Invoke the run method on the Swing event dispatch thread // Sun now recommends you call ALL your GUI methods on the Swing // event thread, even the initial setup. // Could also use invokeAndWait and catch exceptions SwingUtilities.invokeLater( new Runnable() { /** * } fire up a JFrame on the Swing thread */ public void run() { out.println( "Starting" ); final JFrame jframe = new JFrame( TITLE_STRING + " " + VERSION_STRING ); Container contentPane = jframe.getContentPane(); jframe.setSize( width, height ); contentPane.setBackground( Color.YELLOW ); contentPane.setForeground( Color.BLUE ); jframe.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); try { out.println( "acquiring URL" ); JEditorPane jep = new JEditorPane( URL ); out.println( "URL acquired" ); JScrollPane jsp = new JScrollPane( jep, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED ); contentPane.add( jsp ); } catch ( IOException e ) { err.println( "can't find URL" ); contentPane.add( new JLabel( "can't find URL" ) ); } jframe.validate(); jframe.setVisible( true ); // Shows page, with HTML comments erroneously displayed. // The links are not clickable. } } ); }// end main }// end TestHTMLRendering

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  • implement N-Tier Entity Framework 4.0 with DTOs

    - by kathy
    Hi, I'm currently building a web based system and trying to implement N-Tier Entity Framework 4.0 with DTOs in a SOA Architecture. I am having a problem understanding how I should implement the Data Access Layer (DAL) , the Business Logic Layer (BLL) and the Presentation Layer. Let’s suppose that I have a “useraccount” entity has the following : Id FirstName LastName AuditFields_InsertDate AuditFields_UpdateDate In the DAL I created a class “UserAccountsData.cs” as the following : using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace OrderSystemDAL { public static class UserAccountsData { public static int Insert(string firstName, string lastName, DateTime insertDate) { using (OrderSystemEntities db = new OrderSystemEntities()) { return Insert(db, firstName, lastName, insertDate); } } public static int Insert(OrderSystemEntities db, string firstName, string lastName, DateTime insertDate) { return db.UserAccounts_Insert(firstName, lastName, insertDate, insertDate).ElementAt(0).Value; } public static void Update(int id, string firstName, string lastName, DateTime updateDate) { using (OrderSystemEntities db = new OrderSystemEntities()) { Update(db, id, firstName, lastName, updateDate); } } public static void Update(OrderSystemEntities db, int id, string firstName, string lastName, DateTime updateDate) { db.UserAccounts_Update(id, firstName, lastName, updateDate); } public static void Delete(int id) { using (OrderSystemEntities db = new OrderSystemEntities()) { Delete(db, id); } } public static void Delete(OrderSystemEntities db, int id) { db.UserAccounts_Delete(id); } public static UserAccount SelectById(int id) { using (OrderSystemEntities db = new OrderSystemEntities()) { return SelectById(db, id); } } public static UserAccount SelectById(OrderSystemEntities db, int id) { return db.UserAccounts_SelectById(id).ElementAtOrDefault(0); } public static List<UserAccount> SelectAll() { using (OrderSystemEntities db = new OrderSystemEntities()) { return SelectAll(db); } } public static List<UserAccount> SelectAll(OrderSystemEntities db) { return db.UserAccounts_SelectAll().ToList(); } } } And in the BLL I created a class “UserAccountEO.cs” as the following : using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; using OrderSystemDAL; namespace OrderSystemBLL { public class UserAccountEO { public int Id { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public DateTime InsertDate { get; set; } public DateTime UpdateDate { get; set; } public string FullName { get { return LastName + ", " + FirstName; } } public bool Save(ref ArrayList validationErrors) { ValidateSave(ref validationErrors); if (validationErrors.Count == 0) { if (Id == 0) { Id = UserAccountsData.Insert(FirstName, LastName, DateTime.Now); } else { UserAccountsData.Update(Id, FirstName, LastName, DateTime.Now); } return true; } else { return false; } } private void ValidateSave(ref ArrayList validationErrors) { if (FirstName.Trim() == "") { validationErrors.Add("The First Name is required."); } if (LastName.Trim() == "") { validationErrors.Add("The Last Name is required."); } } public void Delete(ref ArrayList validationErrors) { ValidateDelete(ref validationErrors); if (validationErrors.Count == 0) { UserAccountsData.Delete(Id); } } private void ValidateDelete(ref ArrayList validationErrors) { //Check for referential integrity. } public bool Select(int id) { UserAccount userAccount = UserAccountsData.SelectById(id); if (userAccount != null) { MapData(userAccount); return true; } else { return false; } } internal void MapData(UserAccount userAccount) { Id = userAccount.Id; FirstName = userAccount.FristName; LastName = userAccount.LastName; InsertDate = userAccount.AuditFields_InsertDate; UpdateDate = userAccount.AuditFields_UpdateDate; } public static List<UserAccountEO> SelectAll() { List<UserAccountEO> userAccounts = new List<UserAccountEO>(); List<UserAccount> userAccountDTOs = UserAccountsData.SelectAll(); foreach (UserAccount userAccountDTO in userAccountDTOs) { UserAccountEO userAccountEO = new UserAccountEO(); userAccountEO.MapData(userAccountDTO); userAccounts.Add(userAccountEO); } return userAccounts; } } } And in the PL I created a webpage as the following : using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using OrderSystemBLL; using System.Collections; namespace OrderSystemUI { public partial class Users : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { LoadUserDropDownList(); } } private void LoadUserDropDownList() { ddlUsers.DataSource = UserAccountEO.SelectAll(); ddlUsers.DataTextField = "FullName"; ddlUsers.DataValueField = "Id"; ddlUsers.DataBind(); } } } Is the above way the right way to Implement the DTOs pattern in n-tier Architecture using EF4 ??? I would appreciate your help Thanks.

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  • Dynamically loading Assemblies to reduce Runtime Depencies

    - by Rick Strahl
    I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change.  So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. That being said though - I serialized 10,000 objects in 80ms vs. 45ms so this isn't hardly slouchy. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?On occasion dynamic loading makes sense. But there's a price to be paid in added code complexity and a performance hit. But for some operations that are not pivotal to a component or application and only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful tool. Hopefully some of you find this information useful…© Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET  C#   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Python's equivalence?

    - by user304014
    Is there anyway to transform the following code in Java to Python's equivalence? public class Animal{ public enum AnimalBreed{ Dog, Cat, Cow, Chicken, Elephant } private static final int Animals = AnimalBreed.Dog.ordinal(); private static final String[] myAnimal = new String[Animals]; private static Animal[] animal = new Animal[Animals]; public static final Animal DogAnimal = new Animal(AnimalBreed.Dog, "woff"); public static final Animal CatAnimal = new Animal(AnimalBreed.Cat, "meow"); private AnimalBreed breed; public static Animal myDog (String name) { return new Animal(AnimalBreed.Dog, name); } }

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  • Dynamically loading Assemblies to reduce Runtime Dependencies

    - by Rick Strahl
    I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change.  So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. This will change though depending on the size of objects serialized - the larger the object the more processing time is spent inside the actual dynamically activated components and the less difference there will be. Dynamic code is always slower, but how much it really affects your application primarily depends on how frequently the dynamic code is called in relation to the non-dynamic code executing. In most situations where dynamic code is used 'to get the process rolling' as I do here the overhead is small enough to not matter.All that being said though - I serialized 10,000 objects in 80ms vs. 45ms so this is hardly slouchy performance. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?Dynamic loading is not something you need to worry about but on occasion dynamic loading makes sense. But there's a price to be paid in added code  and a performance hit which depends on how frequently the dynamic code is accessed. But for some operations that are not pivotal to a component or application and are only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files adding dependencies and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems like a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful option in your toolset… © Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET  C#   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • GORM ID generation and belongsTo association ?

    - by fabien-barbier
    I have two domains : class CodeSetDetail { String id String codeSummaryId static hasMany = [codes:CodeSummary] static constraints = { id(unique:true,blank:false) } static mapping = { version false id column:'code_set_detail_id', generator: 'assigned' } } and : class CodeSummary { String id String codeClass String name String accession static belongsTo = [codeSetDetail:CodeSetDetail] static constraints = { id(unique:true,blank:false) } static mapping = { version false id column:'code_summary_id', generator: 'assigned' } } I get two tables with columns: code_set_detail: code_set_detail_id code_summary_id and code_summary: code_summary_id code_set_detail_id (should not exist) code_class name accession I would like to link code_set_detail table and code_summary table by 'code_summary_id' (and not by 'code_set_detail_id'). Note : 'code_summary_id' is define as column in code_set_detail table, and define as primary key in code_summary table. To sum-up, I would like define 'code_summary_id' as primary key in code_summary table, and map 'code_summary_id' in code_set_detail table. How to define a primary key in a table, and also map this key to another table ?

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  • Managing of shared resources between classes?

    - by Axarydax
    Imagine that I have a several Viewer component that are used for displaying text and they have few modes that user can switch (different font presets for viewing text/binary/hex). What would be the best approach for managing shared objects - for example fonts, find dialog, etc? I figured that static class with lazily initialized objects would be OK, but this might be the wrong idea. static class ViewerStatic { private static Font monospaceFont; public static Font MonospaceFont { get { if (monospaceFont == null) //TODO read font settings from configuration monospaceFont = new Font(FontFamily.GenericMonospace, 9, FontStyle.Bold); return monospaceFont; } } private static Font sansFont; public static Font SansFont { get { if (sansFont == null) //TODO read font settings from configuration sansFont = new Font(FontFamily.GenericSansSerif, 9, FontStyle.Bold); return sansFont; } } }

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  • C# Reading and Writing a Char[] to and from a Byte[] - Updated with Solution

    - by Simon G
    Hi, I have a byte array of around 10,000 bytes which is basically a blob from delphi that contains char, string, double and arrays of various types. This need to be read in and updated via C#. I've created a very basic reader that gets the byte array from the db and converts the bytes to the relevant object type when accessing the property which works fine. My problem is when I try to write to a specific char[] item, it doesn't seem to update the byte array. I've created the following extensions for reading and writing: public static class CharExtension { public static byte ToByte( this char c ) { return Convert.ToByte( c ); } public static byte ToByte( this char c, int position, byte[] blob ) { byte b = c.ToByte(); blob[position] = b; return b; } } public static class CharArrayExtension { public static byte[] ToByteArray( this char[] c ) { byte[] b = new byte[c.Length]; for ( int i = 1; i < c.Length; i++ ) { b[i] = c[i].ToByte(); } return b; } public static byte[] ToByteArray( this char[] c, int positon, int length, byte[] blob ) { byte[] b = c.ToByteArray(); Array.Copy( b, 0, blob, positon, length ); return b; } } public static class ByteExtension { public static char ToChar( this byte[] b, int position ) { return Convert.ToChar( b[position] ); } } public static class ByteArrayExtension { public static char[] ToCharArray( this byte[] b, int position, int length ) { char[] c = new char[length]; for ( int i = 0; i < length; i++ ) { c[i] = b.ToChar( position ); position += 1; } return c; } } to read and write chars and char arrays my code looks like: Byte[] _Blob; // set from a db field public char ubin { get { return _tariffBlob.ToChar( 14 ); } set { value.ToByte( 14, _Blob ); } } public char[] usercaplas { get { return _tariffBlob.ToCharArray( 2035, 10 ); } set { value.ToByteArray( 2035, 10, _Blob ); } } So to write to the objects I can do: ubin = 'C'; // this will update the byte[] usercaplas = new char[10] { 'A', 'B', etc. }; // this will update the byte[] usercaplas[3] = 'C'; // this does not update the byte[] I know the reason is that the setter property is not being called but I want to know is there a way around this using code similar to what I already have? I know a possible solution is to use a private variable called _usercaplas that I set and update as needed however as the byte array is nearly 10,000 bytes in length the class is already long and I would like a simpler approach as to reduce the overall code length and complexity. Thank Solution Here's my solution should anyone want it. If you have a better way of doing then let me know please. First I created a new class for the array: public class CharArrayList : ArrayList { char[] arr; private byte[] blob; private int length = 0; private int position = 0; public CharArrayList( byte[] blob, int position, int length ) { this.blob = blob; this.length = length; this.position = position; PopulateInternalArray(); SetArray(); } private void PopulateInternalArray() { arr = blob.ToCharArray( position, length ); } private void SetArray() { foreach ( char c in arr ) { this.Add( c ); } } private void UpdateInternalArray() { this.Clear(); SetArray(); } public char this[int i] { get { return arr[i]; } set { arr[i] = value; UpdateInternalArray(); } } } Then I created a couple of extension methods to help with converting to a byte[] public static byte[] ToByteArray( this CharArrayList c ) { byte[] b = new byte[c.Count]; for ( int i = 0; i < c.Count; i++ ) { b[i] = Convert.ToChar( c[i] ).ToByte(); } return b; } public static byte[] ToByteArray( this CharArrayList c, byte[] blob, int position, int length ) { byte[] b = c.ToByteArray(); Array.Copy( b, 0, blob, position, length ); return b; } So to read and write to the object: private CharArrayList _usercaplass; public CharArrayList usercaplas { get { if ( _usercaplass == null ) _usercaplass = new CharArrayList( _tariffBlob, 2035, 100 ); return _usercaplass; } set { _usercaplass = value; _usercaplass.ToByteArray( _tariffBlob, 2035, 100 ); } } As mentioned before its not an ideal solutions as I have to have private variables and extra code in the setter but I couldnt see a way around it.

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