Where with not equal
<> not equal will include NULL column, so if table has null value, consider to add null check statement.
SELECT empid, firstname, lastname, country, region, city
FROM HR.Employees
WHERE region <> N'WA';
SELECT empid, firstname, lastname, country, region, city
FROM HR.Employees
WHERE region <> N'WA'
OR region IS NULL;
Step 1 search on star menu, type ‘command’
click on ‘Open file location’.
Step 2 right click on command in opened folder
Now in ‘Start in’ field, put path you want.
all unit tests in newly added Unit Test Project are not appeared in ‘Test Explorer’
or those unit tests are marked as “Not Run Tests” and never run it no matter how hard you pressure visual studio to run.
do following two steps to fix:
delete following two framework references
Microsoft.VisualStudio.TestPlatform.TestFramework、
Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions
and add Microsoft.VisualStudio.QualityTools.UnitTestFramework
process.env type define
add following code before `process.env.NODE_ENV`
1 2 3 4 5 6 7 | declare var process : {
env: {
NODE_ENV: string
}
}
process.env.NODE_ENV |
define Array
1 2 3 4 5 6 7 8 9 10 11 | export interface INinjaConfig {
username: string;
password: string;
uris: {
uri: string,
pdfUri: string
},
mapping: {
[key: string]: string;
}
} |
define Array of Array Type
1 2 3 4 5 6 7 8 9 10 11 12 | define [[string, number, number]...]
export interface IInfluxDBInfo {
name: string,
tags: {
hostname: string,
ifAlias: string
},
column: string[],
values: Array<[string, number, number]>
} |
nullable variable declare
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | export interface QueryConfig {
limit?: number;
skip?: number;
sort?: {
[key: string]: string;
};
select?: string;
populate?: any;
state?: string;
lean?: boolean;
handleNotFound?: boolean;
archived?: boolean;
publishEvent?: boolean;
dataType?: string;
all?: boolean;
fields?: string[];
childrens: [{
sys_id: string;
name: string;
company: string;
}];
} |
it is very common to see that C# code use @keyword such as @this to escape ‘this’ as keyword to use it like a local variable.
1 2 3 4 5 6 7 8 9 | class @class { public static void @static(bool @bool) { if (@bool) System.Console.WriteLine("true"); else System.Console.WriteLine("false"); } } |
if %include% is lost, VS could not find header.
add sdk
C:\Program Files (x86)\Windows Kits\10\Include into %include% path to fix issue.
Visual Studio 2015 update 3 could throw this exception.
the way to fix it
1. open vs2015 and don’t open any project.
2. go to menu ‘Tools’ -> Nuget Package Manager -> Package Manager Setting
3. once you see dialog pop up successfully without error, click on ‘OK’ button to confirm.
4. open any project. now you could see that Nuget error is gone.
PriorityQueue is a binary heap. Heap is commonly used algorithm. in some area such Graph shortest path and minimum spanning tree, it is very helpful.
both Java and C++ has PriorityQueue, but C# don’t have.
Here is a version of PriorityQueue
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | /// <summary> /// /// </summary> /// <typeparam name="T"></typeparam> public class PriorityQueue<T> where T : IComparable<T> { private List<T> data; private bool isMaxHeap = false; /// <summary> /// /// </summary> public PriorityQueue() { this.data = new List<T>(); } /// <summary> /// /// </summary> /// <param name="isMaxHeap"></param> public PriorityQueue(bool isMaxHeap) { this.data = new List<T>(); this.isMaxHeap = isMaxHeap; } /// <summary> /// /// </summary> /// <param name="item"></param> public void Enqueue(T item) { data.Add(item); int ci = data.Count - 1; // child index; start at end while (ci > 0) { int pi = (ci - 1) / 2; // parent index if(isMaxHeap) { if (data[ci].CompareTo(data[pi]) <= 0) break; } else if (data[ci].CompareTo(data[pi]) >= 0) break; // child item is larger than (or equal) parent so we're done T tmp = data[ci]; data[ci] = data[pi]; data[pi] = tmp; ci = pi; } } /// <summary> /// /// </summary> /// <returns></returns> public T Dequeue() { // assumes pq is not empty; up to calling code int li = data.Count - 1; // last index (before removal) T frontItem = data[0]; // fetch the front data[0] = data[li]; data.RemoveAt(li); --li; // last index (after removal) int pi = 0; // parent index. start at front of pq while (true) { int ci = pi * 2 + 1; // left child index of parent if (ci > li) break; // no children so done int rc = ci + 1; // right child if (isMaxHeap) { if (rc <= li && data[rc].CompareTo(data[ci]) >= 0) // if there is a rc (ci + 1), and it is smaller than left child, use the rc instead ci = rc; if (data[pi].CompareTo(data[ci]) >= 0) break; // parent is smaller than (or equal to) smallest child so done } else { if (rc <= li && data[rc].CompareTo(data[ci]) < 0) // if there is a rc (ci + 1), and it is smaller than left child, use the rc instead ci = rc; if (data[pi].CompareTo(data[ci]) <= 0) break; // parent is smaller than (or equal to) smallest child so done } T tmp = data[pi]; data[pi] = data[ci]; data[ci] = tmp; // swap parent and child pi = ci; } return frontItem; } /// <summary> /// /// </summary> /// <returns></returns> public T Peek() { T frontItem = data[0]; return frontItem; } /// <summary> /// /// </summary> /// <returns></returns> public int Count() { return data.Count; } public override string ToString() { string s = ""; for (int i = 0; i < data.Count; ++i) s += data[i].ToString() + " "; s += "count = " + data.Count; return s; } public bool IsConsistent() { // is the heap property true for all data? if (data.Count == 0) return true; int li = data.Count - 1; // last index for (int pi = 0; pi < data.Count; ++pi) // each parent index { int lci = 2 * pi + 1; // left child index int rci = 2 * pi + 2; // right child index if (lci <= li && data[pi].CompareTo(data[lci]) > 0) return false; // if lc exists and it's greater than parent then bad. if (rci <= li && data[pi].CompareTo(data[rci]) > 0) return false; // check the right child too. } return true; // passed all checks } // IsConsistent } |
1. copy web.config
2. copy service.svc
3. copy dll and pdb file into bin folder
4. in iis, setup a new web instance, and point physical folder address into published folder
setup .net support version correctly for web instance.
5. try http://ip-address:port/service.svc/js or http://ip-address:port/service.svc/jsdebug
The out keyword in generics is used to denote that the type T in the interface is covariant.
check following code.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
class Fruit { }
class Banana : Fruit { }
interface ICovariantSkinned<out T> { }
interface ISkinned<T> { }
class A<T> : ISkinned<T> { }
class B<T> : ICovariantSkinned<T> { }
public static void Main()
{
ISkinned<Banana> a1 = new A<Banana>();
ISkinned<Fruit> a = a1; // compiling error happens here
ICovariantSkinned<Banana> b1 = new B<Banana>();
ICovariantSkinned<Fruit> b = b1; // compiling passed
} |