Ubuntu is distributed on two types of images described below.
Desktop image
The desktop image allows you to try Ubuntu without changing your
computer at all, and at your option to install it permanently later.
This type of image is what most people will want to use. You will need
at least 384MiB of RAM to install from this image.
Server install image
The server install image allows you to install Ubuntu permanently on a
computer for use as a server. It will not install a graphical user
interface.
Electron 10.0.0 منتشر شد
بررسی بهبودهای کارآیی در NET 7.
TL;DR: .NET 7 is fast. Really fast. A thousand performance-impacting PRs went into runtime and core libraries this release, never mind all the improvements in ASP.NET Core and Windows Forms and Entity Framework and beyond. It’s the fastest .NET ever. If your manager asks you why your project should upgrade to .NET 7, you can say “in addition to all the new functionality in the release, .NET 7 is super fast.”
ارجاعات در فایل XML
XML in general is a powerful beast, with so many options available that it quickly gets really complex. The XML Digital Signatures standard is no exception to that. The extra features complexity of XML DSig compared to other signature standard is that one or more different blocks of data can be signed by the same signature block. That data can be the containing XML Document, part of an XML document or some other resource such as a web page. In this post we’ll only look at signing resources in the document containing the signature.
public class HandleConcurrencyExceptionAttribute : FilterAttribute, IExceptionFilter { private PropertyMatchingMode _propertyMatchingMode; /// <summary> /// This defines when the concurrencyexception happens, /// </summary> public enum PropertyMatchingMode { /// <summary> /// Uses only the field names in the model to check against the entity. This option is best when you are using /// View Models with limited fields as opposed to an entity that has many fields. The ViewModel (or model) field names will /// be used to check current posted values vs. db values on the entity itself. /// </summary> UseViewModelNamesToCheckEntity = 0, /// <summary> /// Use any non-matching value fields on the entity (except timestamp fields) to add errors to the ModelState. /// </summary> UseEntityFieldsOnly = 1, /// <summary> /// Tells the filter to not attempt to add field differences to the model state. /// This means the end user will not see the specifics of which fields caused issues /// </summary> DontDisplayFieldClashes = 2 } public HandleConcurrencyExceptionAttribute() { _propertyMatchingMode = PropertyMatchingMode.UseViewModelNamesToCheckEntity; } public HandleConcurrencyExceptionAttribute(PropertyMatchingMode propertyMatchingMode) { _propertyMatchingMode = propertyMatchingMode; } /// <summary> /// The main method, called by the mvc runtime when an exception has occured. /// This must be added as a global filter, or as an attribute on a class or action method. /// </summary> /// <param name="filterContext"></param> public void OnException(ExceptionContext filterContext) { if (!filterContext.ExceptionHandled && filterContext.Exception is DbUpdateConcurrencyException) { //Get original and current entity values DbUpdateConcurrencyException ex = (DbUpdateConcurrencyException)filterContext.Exception; var entry = ex.Entries.Single(); //problems with ef4.1/4.2 here because of context/model in different projects. //var databaseValues = entry.CurrentValues.Clone().ToObject(); //var clientValues = entry.Entity; //So - if using EF 4.1/4.2 you may use this workaround var clientValues = entry.CurrentValues.Clone().ToObject(); entry.Reload(); var databaseValues = entry.CurrentValues.ToObject(); List<string> propertyNames; filterContext.Controller.ViewData.ModelState.AddModelError(string.Empty, "The record you attempted to edit " + "was modified by another user after you got the original value. The " + "edit operation was canceled and the current values in the database " + "have been displayed. If you still want to edit this record, click " + "the Save button again to cause your changes to be the current saved values."); PropertyInfo[] entityFromDbProperties = databaseValues.GetType().GetProperties(BindingFlags.FlattenHierarchy | BindingFlags.Public | BindingFlags.Instance); if (_propertyMatchingMode == PropertyMatchingMode.UseViewModelNamesToCheckEntity) { //We dont have access to the model here on an exception. Get the field names from modelstate: propertyNames = filterContext.Controller.ViewData.ModelState.Keys.ToList(); } else if (_propertyMatchingMode == PropertyMatchingMode.UseEntityFieldsOnly) { propertyNames = databaseValues.GetType().GetProperties(BindingFlags.Public).Select(o => o.Name).ToList(); } else { filterContext.ExceptionHandled = true; UpdateTimestampField(filterContext, entityFromDbProperties, databaseValues); filterContext.Result = new ViewResult() { ViewData = filterContext.Controller.ViewData }; return; } UpdateTimestampField(filterContext, entityFromDbProperties, databaseValues); //Get all public properties of the entity that have names matching those in our modelstate. foreach (var propertyInfo in entityFromDbProperties) { //If this value is not in the ModelState values, don't compare it as we don't want //to attempt to emit model errors for fields that don't exist. //Compare db value to the current value from the entity we posted. if (propertyNames.Contains(propertyInfo.Name)) { if (propertyInfo.GetValue(databaseValues, null) != propertyInfo.GetValue(clientValues, null)) { var currentValue = propertyInfo.GetValue(databaseValues, null); if (currentValue == null || string.IsNullOrEmpty(currentValue.ToString())) { currentValue = "Empty"; } filterContext.Controller.ViewData.ModelState.AddModelError(propertyInfo.Name, "Current value: " + currentValue); } } //TODO: hmm.... how can we only check values applicable to the model/modelstate rather than the entity we saved? //The problem here is we may only have a few fields used in the viewmodel, but many in the entity //so we could have a problem here with that. //object o = propertyInfo.GetValue(myObject, null); } filterContext.ExceptionHandled = true; filterContext.Result = new ViewResult() { ViewData = filterContext.Controller.ViewData }; } }
background-clip
is one of those properties I've known about for years, but rarely used. Maybe just a couple of times as part of a solution to a Stack Overflow question. Until last year, when I started creating my huge collection of sliders. Some of the designs I chose to reproduce were a bit more complex and I only had one element available per slider, which happened to be an input
element, meaning that I couldn't even use pseudo-elements on it. Even though that does work in certain browsers, the fact that it works is actually a bug and I didn't want to rely on that. All this meant I ended up using backgrounds, borders, and shadows a lot. I also learned a lot from doing that and this article shares some of those lessons.
فایل ARCHITECTURE.md
If you maintain an open-source project in the range of 10k-200k lines of code, I strongly encourage you to add an ARCHITECTURE document next to README and CONTRIBUTING. Before going into the details of why and how, I want to emphasize that this is not another “docs are good, write more docs” advice. I am pretty sloppy about documentation, and, eg, I often use just “simplify” as a commit message. Nonetheless, I feel strongly about the issue, even to the point of pestering you:-)
Any experienced .NET developer knows that even though .NET applications have a garbage collector, memory leaks occur all the time. It’s not that the garbage collector has bugs, it’s just that there are ways we can (easily) cause memory leaks in a managed language.
Memory leaks are sneakily bad creatures. It’s easy to ignore them for a very long time, while they slowly destroy the application. With memory leaks, your memory consumption grows, creating GC pressure and performance problems. Finally, the program will just crash on an out-of-memory exception.
In this article, we will go over the most common reasons for memory leaks in .NET programs. All examples are in C#, but they are relevant to other languages.