.net-4.0

问题 I have a model similar to this: public class SampleModel { public Product Product { get; set; } } And in my controller I get an exception trying to print out @Html.TextBoxFor(p => p.Product.Name) This is the error: Exception: An expression tree may not contain a dynamic operation If anyone can give me some clues on how to fix this I would really appreciate it! 回答1: It seems to me that you have an untyped view. By default, Razor views in MVC3 RC are typed as dynamic . However, lambdas do not

问题 I have a model similar to this: public class SampleModel { public Product Product { get; set; } } And in my controller I get an exception trying to print out @Html.TextBoxFor(p => p.Product.Name) This is the error: Exception: An expression tree may not contain a dynamic operation If anyone can give me some clues on how to fix this I would really appreciate it! 回答1: It seems to me that you have an untyped view. By default, Razor views in MVC3 RC are typed as dynamic . However, lambdas do not

问题 I'm a bit perplexed on how to manage SmtpClient now that it is disposable, especially if I make calls using SendAsync. Presumably I should not call Dispose until SendAsync completes. But should I ever call it (e.g., using "using"). The scenario is a WCF service which mails out email periodically when calls are made. Most of the computation is fast, but the sending of email can take a second or so, so Async would be preferable. Should I create a new SmtpClient each time I send mail? Should I

问题 I'm a bit perplexed on how to manage SmtpClient now that it is disposable, especially if I make calls using SendAsync. Presumably I should not call Dispose until SendAsync completes. But should I ever call it (e.g., using "using"). The scenario is a WCF service which mails out email periodically when calls are made. Most of the computation is fast, but the sending of email can take a second or so, so Async would be preferable. Should I create a new SmtpClient each time I send mail? Should I

问题 I am using Parallel.ForEach and I am doing some database updates, now without setting MaxDegreeOfParallelism , a dual core processor machine results in sql client timeouts, where else quad core processor machine somehow does not timeout. Now I have no control over what kind of processor cores are available where my code runs, but is there some settings I can change with MaxDegreeOfParallelism that will probably run less operations simultaneously and not result in timeouts? I can increase

问题 i've included a directX player in c# .net 4.0 app that is included here ( answer2 ) . The problem is that when i try to initialize the object ( i.e. Player mPlayer=new Player()) this error occurs : Mixed mode assembly is built against version 'v1.1.4322' of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information. Anyone knows what it can be? 回答1: You need to add an app.Config file and set useLegacyV2RuntimeActivationPolicy to true. This is required to

问题 First, I have read the following: Connect case VS case and especially this channel9 post So, from the last bullet, I really think there is no way around this, but I had to see if I could get a definitive answer as my team would like to upgrade from .NET 4.0 to .NET 4.5. However, we have to support XP. Is there no possibility of going to .NET 4.5 if we want to support XP? The only thing I could think of is creating two separate solutions, but then the codebases would have to diverge if we used

问题 First, I have read the following: Connect case VS case and especially this channel9 post So, from the last bullet, I really think there is no way around this, but I had to see if I could get a definitive answer as my team would like to upgrade from .NET 4.0 to .NET 4.5. However, we have to support XP. Is there no possibility of going to .NET 4.5 if we want to support XP? The only thing I could think of is creating two separate solutions, but then the codebases would have to diverge if we used

问题 I have created a cache using the MemoryCache class. I add some items to it but when I need to reload the cache I want to clear it first. What is the quickest way to do this? Should I loop through all the items and remove them one at a time or is there a better way? 回答1: Dispose the existing MemoryCache and create a new MemoryCache object. 回答2: The problem with enumeration The MemoryCache.GetEnumerator() Remarks section warns: "Retrieving an enumerator for a MemoryCache instance is a resource

问题 Recently when being interviewed, I got this question. Q: Have you written multithreaded applications? A: Yes Q: Care to explain more? A: I used Tasks (Task Parallel library) to carry out some tasks like waiting for some info from internet while loading UI . This improves my application usability. Q: But, just you have used TPL means that you have written an multithreaded application? Me: (Not sure what to say1) So, whats exactly a multi-threaded application? Is it different from using Tasks ?