delegates

问题 I'm trying to make a generic method that returns the string version of an expression: public string GetExpressionString(Expression<Func<T, bool>> expr) where T: class { return exp.Body.ToString(); } Cannot resolve symbol T Works well if I change T to a hard coded type. What did I miss? 回答1: You'll need to declare T as a generic type parameter on the method: public string GetExpressionString<T>(Expression<Func<T, bool>> exp) where T: class { return exp.Body.ToString(); } // call like this

问题 I'm trying to make a generic method that returns the string version of an expression: public string GetExpressionString(Expression<Func<T, bool>> expr) where T: class { return exp.Body.ToString(); } Cannot resolve symbol T Works well if I change T to a hard coded type. What did I miss? 回答1: You'll need to declare T as a generic type parameter on the method: public string GetExpressionString<T>(Expression<Func<T, bool>> exp) where T: class { return exp.Body.ToString(); } // call like this

问题 Question : How can we use Invoke(...) method in a Microsoft Office 2010-2016 VSTO project. Or, are there any work around, alternatives etc for a VSTO project? Background : I am trying to implement a source code of a third party Windows Forms application into my Microsoft Office VSTO add-in project. The third party vendor has provided its users a sample/example as a Windows Form project with source code and has asked its users to mimic that code to their other projects (WPF, Office Solutions

问题 Question : How can we use Invoke(...) method in a Microsoft Office 2010-2016 VSTO project. Or, are there any work around, alternatives etc for a VSTO project? Background : I am trying to implement a source code of a third party Windows Forms application into my Microsoft Office VSTO add-in project. The third party vendor has provided its users a sample/example as a Windows Form project with source code and has asked its users to mimic that code to their other projects (WPF, Office Solutions

问题 I'm using PowerDNS authoritative server and pdns-mysql-backend. And I 'm trying to create a subdomain and delegate the external NS to it. But I can't find a proper doc or example for it. I just need to create NS records for subdomain? 1. existing domain is "example.com" 2. sub-domain that I want to create is "test.example.com" 3. external NS is "ns1.book.com" and I have created records to mysql like below. "domains table" id |name |master |last_check | type |notified_serial | account --------

问题 I'm using PowerDNS authoritative server and pdns-mysql-backend. And I 'm trying to create a subdomain and delegate the external NS to it. But I can't find a proper doc or example for it. I just need to create NS records for subdomain? 1. existing domain is "example.com" 2. sub-domain that I want to create is "test.example.com" 3. external NS is "ns1.book.com" and I have created records to mysql like below. "domains table" id |name |master |last_check | type |notified_serial | account --------

问题 I'm using PowerDNS authoritative server and pdns-mysql-backend. And I 'm trying to create a subdomain and delegate the external NS to it. But I can't find a proper doc or example for it. I just need to create NS records for subdomain? 1. existing domain is "example.com" 2. sub-domain that I want to create is "test.example.com" 3. external NS is "ns1.book.com" and I have created records to mysql like below. "domains table" id |name |master |last_check | type |notified_serial | account --------

问题 I have a generic method public delegate void Handler<T>(T val); I enable users to register to events and provide this delegate. I need to save the list of delegate according to their types. I tried saving in a dictionary of Type and object. when adding the method I cast it to a List<Handler<T>> according to the T. but then when an event occurred I do not have the T so cannot cast to the relevant list of generic handlers (I do have the Type but not the T) I solved this by saving methodInfo

问题 I'm having a problem with foreach(var category in categories) { foreach(var word in words) { var waitCallback = new WaitCallback(state => { DoSomething(word, category); }); ThreadPool.QueueUserWorkItem(waitCallback); } } When the DoSomething gets executed, it receives the latest value for each captured variable instead of the value I desired. I can imagine a solution for this, but it imagine you guys can come up with better solutions 回答1: The canonical way to solve this is to copy the values

问题 What I'm looking for is probably not going to be possible without resorting to reflection. If that's the case, I'd still want to know the best way to pull it off. Essentially, this is what I want my code to look like: var instance = new MyClass(); instance.Add<int, string>(x => x.ToString()); instance.Add<string, Warehouse>(x => Warehouse.LookupByName(x)); instance.Add<Warehouse, IList<Supplier>>(x => x.Suppliers()); instance.Chain(3); // should call each lambda expression in turn My question