.net

问题 When to replace a DataGridViewColumnHeaderCell with a custom HeaderCell (here: CustomDataGridViewColumnHeaderCell ), when the DataSource of a DataGridView is already set to a DataTable object and also preserve the text of the previous HeaderCell, which is set to the name of the corresponding Column of the DataTable? I have a custom header class for a DataGridView : public class CustomDataGridViewColumnHeaderCell : DataGridViewColumnHeaderCell { // adds a button to the header } A DataTable is

问题 I'm trying to download an html document from Amazon but for some reason I get a bad encoded string like "��K��g��g�e". Here's the code I tried: using (var webClient = new System.Net.WebClient()) { var url = "https://www.amazon.com/dp/B07H256MBK/"; webClient.Encoding = Encoding.UTF8; var result = webClient.DownloadString(url); } Same thing happens when using HttpClient: var url = "https://www.amazon.com/dp/B07H256MBK/"; var httpclient = new HttpClient(); var html = await httpclient

问题 I'm trying to download an html document from Amazon but for some reason I get a bad encoded string like "��K��g��g�e". Here's the code I tried: using (var webClient = new System.Net.WebClient()) { var url = "https://www.amazon.com/dp/B07H256MBK/"; webClient.Encoding = Encoding.UTF8; var result = webClient.DownloadString(url); } Same thing happens when using HttpClient: var url = "https://www.amazon.com/dp/B07H256MBK/"; var httpclient = new HttpClient(); var html = await httpclient

问题 If I type the following: public Response GetArticles(string Filter = String.Empty) { //Body } Visual Studio gives me this error: Default parameter value for 'Filter' must be a compile-time constant If I change the String.Empty to the classic "" it is fixed. But I'm still curious about what is wrong with the String.Empty and its behavior. 回答1: Why is String.Empty an invalid default parameter? Because "Default parameter value for 'Filter' must be a compile-time constant". And String.Empty is

问题 Can anyone please explain to me what happens behind the scenes when you use ternary operator? does this line of code: string str = 1 == 1 ? "abc" : "def"; is generated as a simple if / else statement? Consider the following: class A { } class B : A { } class C : A { } Now using ternary expression as follows: A a1 = 1 == 1 ? new B() : new C(); this doesn't even compile with this error: Type of conditional expression cannot be determined because there is no implicit conversion between

问题 Can anyone please explain to me what happens behind the scenes when you use ternary operator? does this line of code: string str = 1 == 1 ? "abc" : "def"; is generated as a simple if / else statement? Consider the following: class A { } class B : A { } class C : A { } Now using ternary expression as follows: A a1 = 1 == 1 ? new B() : new C(); this doesn't even compile with this error: Type of conditional expression cannot be determined because there is no implicit conversion between

问题 We are running some code in both VisualStudio process context (x86 context) and out of VisualStudio context (x64 context). I notice the following code provides a different result in both context (100000000000 in x86 and 99999997952 in x64) float val = 1000f; val = val * val; return (ulong)(val * 100000.0f); We need to obtain a ulong value from a float value in a reliable way, no matter the context and no matter the ulong value, it is just for hashing purpose. I tested this code in both x64

问题 i am trying to develop a class for unlimited size integer values, all i need is to make a new custom constant suffix used with the assign operator. For example: lets assume the class name is BigInt and the Suffix created is B the assign statement will be like this // B character will tell the compiler about the New Data Type BigInt x = 111111111111111111111111111111111111111111111111B; is there any way to achieve this? Special Regards 回答1: No, there isn't any way to do this in C# at this time

问题 I have a service which as it's coming up invokes the Start() method on a TcpListener instance. This listener is using a port that is not common and not known to be used by any other services. Very very rarely for a span of minute or so it experiences an odd error. For a minute the service (which on failure restarts immediately) back to back crashes on the following exception: SocketException at System.Net.Sockets.Socket.DoBind(System.Net.EndPoint, System.Net.SocketAddress) at System.Net

问题 We have an application that Generates a hash code on a string Saves that hash code into a DB along with associated data Later, it queries the DB using the string hash code for retrieving the data This is obviously a bug because the value returned from string.GetHashCode() varies from .NET versions and architectures (32/64 bit). To complicate matters, we're too close to a release to refactor our application to stop serializing hash codes and just query on the strings instead. What we'd like to