.net-4.0 – Page 2 – Make Me Engineer

Validation does not work when I use Validator.TryValidateObject

June 2, 2023 by Tarik

I found the answer here: http://forums.silverlight.net/forums/p/149264/377212.aspx MVC recognizes the MetaDataType attribute, but other projects do not. Before validating, you need to manually register the metadata class: TypeDescriptor.AddProviderTransparent( new AssociatedMetadataTypeTypeDescriptionProvider(typeof(Customer), typeof(CustomerMetadata)), typeof(Customer)); var isValid = Validator.TryValidateObject(new Customer(), context, results, true);

ValidateCredentials returns true for unknown user?

June 2, 2023 by Tarik

Some amount of googling later (not that I’ve been in and out of google all day trying to find this anyway), I’ve found the answer. Put simply, if the Guest account is enabled in the domain, ValidateCredentials will return TRUE for an unknown user. I’ve just checked the status of the guest user in development.company.com, … Read more

SetWindowsHookEx failing in .NET 4.0 on 32-bit machine with “module not found”?

June 1, 2023 by Tarik

Yup, I think you understand what’s going on. SetWindowsHookEx() requires a valid module handle, and verifies it, but it doesn’t actually use it when you set a low-level hook. You just need a valid handle, it doesn’t matter which specific one. Calling LoadLibrary(“user32.dll”) is a good way to get a handle, that DLL will always … Read more

How Can I add properties to a class on runtime in C#?

May 31, 2023 by Tarik

You cannot extend an existing class with new members at runtime. However, you can create a new class using System.Reflection.Emit that has the existing class as base class. typeBuilder.SetParent(typeof(MyClass)); typeBuilder.DefineProperty(“Prop1”, …, typeof(System.Int32), null); … See TypeBuilder.DefineProperty Method (String, PropertyAttributes, Type, Type[]) for a full example.

Inserting Certificate (with privatekey) in Root, LocalMachine certificate store fails in .NET 4

May 30, 2023 by Tarik

I had exactly the same problem and the solution turned out to be really simple. All I had to do is to pass X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet to X509Certificate2’s ctor. Now you are using the DotNetUtilities to convert the bouncycastle certificate to the .net one, but the helper method creates the .net cert with the DefaultKeySet … Read more

Is there a way to check whether unicode text is in a certain language?

May 29, 2023 by Tarik

You can use regular expression to match with Supported Named Blocks: private static readonly Regex cjkCharRegex = new Regex(@”\p{IsCJKUnifiedIdeographs}”); public static bool IsChinese(this char c) { return cjkCharRegex.IsMatch(c.ToString()); } Then, you can use: if (sometext.Any(z=>z.IsChinese())) DoSomething();

TaskCreationOptions.LongRunning option and ThreadPool

May 29, 2023 by Tarik

Yes, LongRunning forces the creation of a new thread outside the pool. Here’s some pseudo-disassembled code from the latest framework version: … if (task.Options HasFlag LongRunning) then create new Thread thread thread.Start(task) … Edit: converted from ugly C# to pseudocode.

System.Threading.Timer not firing after some time

May 28, 2023 by Tarik

Are you keeping a reference to your timer somewhere to prevent it being garbage collected? From the docs: As long as you are using a Timer, you must keep a reference to it. As with any managed object, a Timer is subject to garbage collection when there are no references to it. The fact that … Read more

Parallel.For(): Update variable outside of loop

May 26, 2023 by Tarik

You can’t do this. sum is being shared across you parallel threads. You need to make sure that the sum variable is only being accessed by one thread at a time: // DON’T DO THIS! Parallel.For(0, data.Count, i => { Interlocked.Add(ref sum, data[i]); }); BUT… This is an anti-pattern because you’ve effectively serialised the loop … Read more

WPF slow to start on x64 in .NET Framework 4.0

May 26, 2023 by Tarik

Actually there’s 2 main reasons that the default project type for WPF applications is x86. Intellitrace debugging only works with x86 and that would look pretty bad if the default project templates didn’t work with one of their star features. Many developers were still not aware of the fact that their AnyCPU exe’s would run … Read more