Today, we’re releasing .NET 5.0 Preview 2. It contains a set of smaller features and performance improvements. We’re continuing to work on the bigger features that will define the 5.0 release, some of which are starting to show up as initial designs at dotnet/designs.
Here are a couple of the most relevant improvements you may want to verify:
Response.Body.Write
System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.
BenchmarkDotNet v0.10.13 has been released! This release includes:
obj and as). (See #541)
The Tiered Compilation feature changes the premise by allowing .NET to have multiple compilations for the same method that can be hot-swapped at runtime.
Web-based applications run smoother if instead of using the traditional form method, they use JavaScript to post data to the server and to update the user interface after posting data: It also makes it easier to keep POST and GET actions separated. SignalR makes it even slicker; it can even update multiple pages at the same time. Is it time to use JavaScript to post data rather than posting via the browser the traditional way?
public int CalculateElapsedDays(DateTime from)
{
DateTime now = DateTime.Now;
return (now - from).Days;
} public static int CalculateElapsedDays(DateTime from, DateTime now) => (now - from).Days;
public int Divide(int numerator, int denominator)
{
return numerator / denominator;
} var result = Divide(1,0);
public static int Divide(int numerator, NonZeroInt denominator)
{
return numerator / denominator.Value;
} Func<int, bool> isMod2 = x => x % 2 == 0; var list = Enumerable.Range(1, 10); var evenNumbers = list.Where(isMod2);
public static IEnumerable<T> Where<T>(this IEnumerable<T> ts, Func<T, bool> predicate)
{
foreach (T t in ts)
if (predicate(t))
yield return t;
} <h1>News</h1> <div>Welcome to our site!</div> <h2>World</h2> <h3>Title 1</h3> <div>description 1.</div> <h2>Science</h2> <h3>Title 2</h3> <div>description 2.</div>
var headings = document.querySelectorAll('h2, h3');
for (var i = 0; i < headings.length; i++) {
if (headings[i].tagName === 'H2') {
headings[i].style.color = 'blue';
}
else {
headings[i].style.color = 'green';
}
} <h2 style="color: blue">….</h2> <h3 style="color: green">….</h3>
<h2>World</h2>
...
<h2>Science</h2>
<script>
var headings = document.querySelectorAll('h2');
for (var i = 0; i < headings.length; i++) {
headings[i].style.color = 'blue';
headings[i].style.fontWeight = 'bold';
}
</script> headings[i].style['font-weight'] = 'bold';
var headings = document.querySelectorAll('h2');
for (var i = 0; i < headings.length; i++) {
headings[i].style.cssText = 'color: blue; font-weight: bold';
} h2 { color: blue; }
h3 { color: green; } <link href="styles.css" rel="style sheet">
<style>
h2 { color: blue; }
h3 { color: green; }
</style> var sheet = document.styleSheets[0];
sheet.insertRule('h2 { font-style: italic; }', sheet.cssRules.length - 1); // hide an element $element.hide(); // show it again $element.show();
element.setAttribute('hidden', ''); element.removeAttribute('hidden'); 
<style>
.box {
padding: 10px;
margin: 5px;
border: 3px solid;
display: inline-block;
}
</style>
<span class="box">a box</span> // returns 38
var clientHeight = document.querySelector('.box').clientHeight;
// returns 55
var clientWidth = document.querySelector('.box').clientWidth; // returns 44
var offsetHeight = document.querySelector('.box').offsetHeight;
// returns 61
var offsetWidth = document.querySelector('.box').offsetWidth;