parameters

问题 I used this guide as a starting point for creating a messaging system from scratch. Everything worked fine. But for some reason, whenever I now try to create a new conversation by clicking in my view the following link <%= link_to 'Message me', conversations_path(sender_id: current_user.id, recipient_id: @user.id), class: 'btn btn-primary', method: :post %> I encounter the error: found unpermitted parameters: _method, authenticity_token Here are the params: {"_method"=>"post", "authenticity

问题 I'm in the middle of creating a button that uses core data to save a name, xCoordinate, and yCoordinate of a point annotation. I can successfully persist the name, but I keep getting this error when I try to save a coordinate. I've logged the correct data, I just can't seem to save it. When I try to setValue for the newPOI, I get an error that reads: Sending 'float' to parameter of incompatible type 'id'. In the data model, the attribute is set to float. self.latitude and self.longitude are

问题 Yes, I know how to create an SDL thread. int myfunc(void* data) { //my code... } SDL_CreateThread* mythread=SDL_CreateThread(myfunc,NULL); But what if i want to do something like: int myfunc(void* data,int myparameter1,char myparameter2) { //my code... } SDL_CreateThread* mythread=SDL_CreateThread(myfunc,NULL,42,'c'); i.e how to create a thread for a function with more than one parameters (parameters excluding the usual 'void* data') If this is not possible can you suggest any method by which

问题 This is my code class MyException extends Exception { public function __construct($message, $code=0, Exception $previous = null) { parent::__construct($message,$code,$previous); } public function __toString() { return __CLASS__. ":[{$this->code}]:{$this->message}\n"; } } Here is the error Fatal error: Wrong parameters for Exception([string $exception [, long $code ]]) on line 5 means on this line parent::__construct($message,$code,$previous); What is going wrong? 回答1: As noted in the comments

问题 The first thing I do in a public method is to validate every single parameter before they get any chance to get used, passed around or referenced, and then throw an exception if any of them violate the contract. I've found this to be a very good practice as it lets you catch the offender the moment the infraction is committed but then, quite often I write a very simple getter/indexer such as this: private List<Item> m_items = ...; public Item GetItemByIdx( int idx ) { if( (idx < 0) || (idx >=

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: C#: What is the use of “ref” for Reference-type variables? Hi, Does it make sense to pass a "reference type" to a method as a parameter with 'ref' key? Or it is just nonsense as it is already a reference type but not a value type? Thanks! 回答1: It lets you change the reference variable itself , in addition to the object it's pointing to . It makes sense if you think you might make the variable point to a

问题 I have a URL in my app.js containing routes. lets say the url is: /api/:opt1/:opt2/:opt3/users I want that my url will work in any case, i should able to ignore the optional parameters (opt1, opt2 or opt3, may be all or few). How can I achieve this. Is there any way that I can call $location.path('/users') , and I can specify also what are the values of the optional parameters? 回答1: Optional route parameters are marked with ? , like this: `/users/:id?` Then this route matches both /users and

问题 When I'm defining a parameter, like: PARAMETER pa_date TYPE d DEFAULT sy-datum. How do I change "pa_date" to something else when the app is launched? I want to change it to something like "choose date". Any Ideas? 回答1: The Correct Menu Path is: Goto (Alt-G) -> Text Elements (T) -> Selection Texts (S) Once there you can Type in the Text you want OR click the "Dictionary Ref." Checkbox. Doing this will keep your report selections a bit more standard, provided that you use the correct dictionary

问题 I have a PowerShell script CSV2JSON.ps1 with the following code: param( [String]$FieldSeparator=",", [String[]]$Header ) $input | ConvertFrom-Csv -Delimiter $FieldSeparator -Header $Header | ConvertTo-JSON If I call it as .\CSV2JSON.ps1 -FieldSeparator "|" -Header "name|age" it works fine. However, if I drop the optional parameter Header , the ConvertFrom-Csv cmdlet complains that Header cannot be null: ConvertFrom-Csv : Cannot validate argument on parameter 'Header'. The argument is null.

问题 My app requires the following parameters of mobile network: MCC (Mobile Country Code) MNC (Mobile Network Code) LAC (Location area code) CID (Cell identifier) cell's signal strength And for Wi-Fi: MAC-adress signal strength Also I need a device IP-adress for both variants. Is there any API to get these parameters on Windows Phone 7? I can't find anything. 回答1: Access to this information is not made provided. Presumably due to possible privacy/security related issues. Additionally, if you