C # tips-2

I wrote some tips for summary in normal development last time. I will continue to add some more.

1. simplify writing with multiple using.

We often encounter the need to use multiple using objects, at this time we may writeCode:

  Using(Class1 C1= NewClass1 (someparam1 ))
{
Using(Class2 C2= NewClass2 (someparam2 ))
{
//Todo: Add function code here
}
}
 

In fact, we can simplify writing:

  Using(Class1 C1= NewClass1 (someparam1), class2 C2= NewClass2 (someparam2 ))
{
//Todo: Add function code here
}
 

2. In many cases, we may write the following code to determine whether a string is one of several specified strings:

   code highlighting produced by actipro codehighlighter (freeware) 
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 -->  bool   nameexists (  string   name) {
   return   name  = " zhangsan " ||  name  = " Li Si " ||  name  = " Wang Wu " ||  name  = " Zhao Liu "; 
} 

However, there will actually be a simpler way of writing in the 3.0 s:

 
  BoolNameexists (StringName ){
Return New[] {"Zhang San", "Li Si", "Wang Wu", "Zhao Liu"}. Contains (name );
}
 

Or, if this judgment is frequent, we can also use the extension method:

  Public     Static    Bool  In (  This     String  Name,  Params     String  [] Names)
{
  Foreach  (  String  Specialname  In  Names)
{
  If (Name  ! =  Specialname)  Return     False  ;
}
  Return     True  ;
}

VaR name  =  "  Test  "  ;
Console. Write (name. In (  " Zhang San  "  , "Li Si", "Wang Wu", "Zhao Liu "); 

3. when comparing strings, we sometimes ignore case-sensitivity comparisons. You may write the code as follows: str1.toupper () = str2.toupper (). However, the string object provides many better methods, for example, str1.equals (str2, stringcomparison. ordinalignorecase)

4 .?? This feature is used to specify the default value when the object is null. We can use this feature to bind multiple default values.

String result = var1 ?? Var2 ?? Var3 ?? String. empty;

5. This usage is not recommended, but you can name classes or methods in non-English languages such as Chinese, such:

 
  Public StringMethod 1 (){
Return"Xxxxxxx ";
}
 

In addition, you can even use escape characters to name them:

 
  Public StringTest \ u9999 ha (){
Return "Aaa";
}
 

The actual method called is: Test xiangha ();

6. in C #, we can also create anonymous intra-row functions similar to JS, such:

  VaR var1= NewFunc<String>(()=>{
Return"Test ";
})();
 

I hope these summaries will also help readers.