c# - List of Interfaces vs. List of Derived Type - Cannot Convert Expression Type to Return Type -

-

यह क्यों काम करता है: 

  सार्वजनिक IList & lt; ICoupon & gt; GetCouponsForSite (स्ट्रिंग साइटस्लाग) {var कूपन = _db.Coupons.Where (x = & gt; x.Site.slug == siteSlug)। चुनें (x = & gt; नया कूपन (x.id)); Var सूची = नई सूची & lt; ICoupon & gt; (); विदेशी मुद्रा (कूपन में विभिन्न कूपन) {list.Add (कूपन); } वापसी सूची; }

लेकिन यह काम नहीं करता है (त्रुटि - प्रकार वापस जाने के लिए अभिव्यक्ति प्रकार परिवर्तित नहीं कर सकते): 

  सार्वजनिक IList & LT; ICoupon & gt; GetCouponsForSite (स्ट्रिंग साइटस्लाग) {वापसी _db.Coupons.Where (x = & gt; x.Site.slug == siteSlug)। चयन करें (x = & new ;;;;;;;;;; x; नया कूपन (x.id))। ToList (); }

क्योंकि db.Coupons ... ToList () एक लौटता है & lt ; आईआईएलआईटी & lt; ICoupon & gt; के बजाय; कूपन & gt; IList & lt; कूपन & gt; IList & lt; ICoupon & gt; से प्राप्त नहीं करता है क्योंकि C # 3 सामान्य विचरण का समर्थन नहीं करता है यह अभी भी इस मामले में प्राप्त नहीं होगा (सी # 4 सामान्य विचरण का समर्थन करता है, लेकिन विचार करें जो कोई भी एक IList है & lt प्राप्त करता है कि;। ICoupon & gt;। इसे में एक SomeEvilTypeThatImplementsICoupon सामान के लिए कोशिश कर सकते लेकिन एक IList है & lt ; कूपन & gt;।। स्वीकार नहीं कर सका क्योंकि SomeEvilTypeThatImplementsICoupon कूपन से निकाले जाते हैं नहीं है इस परिवर्तनीयता मुद्दे की चर्चा के लिए देखें यद्यपि एक अलग संदर्भ में, और एरिक लिप्‍पर्ट लेख वहाँ से जुड़े)

< ICoupon & gt; है, जो उन्हें <> कुछ भी है कि ICoupon लागू करता हो सकते हैं, और फिर कुछ कूपन उस सूची में वस्तुओं डालता p> (आपका पहला टुकड़ा, इसके विपरीत, स्पष्ट रूप से एक सूची से & lt निर्माण करती है। अब अगर रिसीवर इसे में SomeEvilTypeThatImplementsICoupon प्रहार करने के लिए फैसला करता है, सब कुछ ठीक है, क्योंकि सूची किसी भी ICoupon ही नहीं, वास्तविक कूपन वस्तुओं धारण करने के लिए बनाया गया था।)


Comments

Post a Comment

Popular posts from this blog

c# - How to capture HTTP packet with SharpPcap -

-
I would like to capture all incoming HTTP packets on my machine. To do this, I am using SharpPcap which is a WinPcap The cover is. SharpPcap works very well, but it captures TCP packets and what it wants to do for me is a very low level. Does anyone know how can I easily get full HTTP requests / reactions from all these TCP packets? Thanks SharpPcap is already able to capture the packet in the same way That's what the virus does (just in the code instead of the GUI). And you can either either parse them directly or you can put them in the drive in the common .pcap file format. The steps to parse the capture are: Open a connection at any time Loop a while Or start capturing using an event callback Parsing the raw packet for the type you want If you are reading .PPP dump files In addition to calling you an offline capture reader is almost the same, there is no need to select an interface, and you can set the majority There is no need to do the modes. All st
Read more

jquery - SimpleModal Confirm fails to submit form -

-
I am trying to confirm jQuery to show yes / no confirmation when I submit a form. I had modified (in the last list) to capture and block form submissions. However, it only works with jQuery 1.2.6, a recent upgrade stops 1.3.2, if yes is clicked, then by submitting the form. But I can not understand what is wrong / inconsistent in my code now. Demo (which works in both versions of a simple window.href implementation). $ (document) .ready (function () {$ ('input.delete'). Click (function (e) {e.preventDefault (); var target = $ (e .target); Confirm ("Really delete this event?", Function () {target.click ()});});}); How about something like this? The idea of ​​catching clicks (and fire!) On the submitted event is not click event. $ (document) .ready (function () {$ ('# myForm'). Submit (function () {var f = this; Confirm (" Remove? ", Function () {$ (f). Submit ();}) Return; Return the initial session;}}}}; Hope That this is som
Read more

php - Multiple Select with Explode: only returns the word "Array" -

-
By using Wordpress I have created a multiple selection box so that users can select categories to exclude. When the page is initially loaded, I see my predefined default option. However, when I select a new value and I save ... I only see the word "Array" and have not chosen anything else? & lt; Class = "amultiple" id = "& lt; php echo $ value ['id'] ;? gt;" name = "& gt; php echo $ value ['id'] ;; gt; []" Multiple = "multiple" size = "8" & gt; & Lt ;? Php global option; Foreign currency ($ value as value $) {if (get_settings ($ value ['id']) === FALSE {$$ value ['id'] = $ value ['std']; } And {$$ value ['id'] = get_settings ($ value ['id']); }} $ Ranges = & amp; Amp; Categories ('type = post & orderbiz = name & amp; hide_empty = 1'); If ($ ranges) {$ ex_cat = implode (',', $ tt_cat_exclude); Forex Currency ($ range a
Read more