如何在C＃中的一個類的多個實例之間共享一個值？

Question

我正在編寫一個類庫供我們公司的一些工程軟件使用。該庫用於定義結構鋼形狀的屬性。在我的每個類對象中，我都需要去指定的文件夾並查找一些xml數據。

我怎麼能建立一個共同的變量我可以設置庫類外實例篩選之間共享（如下面的代碼是可能的）

class Program 
{ 
    static void Main(string[] args) 
    { 
     string someCommonVarialble = @"c:\some\path\where\the\xmlData\are\stored"; 

     // create some steel shapes 
     SteelBeamShape myBeam1 = new SteelBeamShape("W6x9"); 
     SteelBeamShape myBeam2 = new SteelBeamShape("W10x22"); 
     SteelPipeShape myPipe1 = new SteelPipeShape("10odx.375wall"); 
     SteelPipeShape myPipe2 = new SteelPipeShape("24odx.750wall"); 

     // do some work with objects here 
    } 
} 

public class SteelBeamShape 
{ 
    // constructor 
    public SteelBeamShape(string SteelBeamNominalValue) 
    { 
     // look up some properties base on nominal value in XML tables 
     this.xmlDataPath = someCommonVariable; 

     // do stuff .... 
    } 
} 

public class SteelPipeShape 
{ 
    // constructor 
    public SteelPipeShape(string SteelPipeNominalValue) 
    { 
     // look up some properties base on nominal value in XML tables 
     this.xmlDataPath = someCommonVariable; 

     // do stuff .... 
    } 
} 

}

Answer 1

要在不同的類之間共享一個共同的值，您需要從共同祖先派生的類。你的情況，你可以定義

public class SteelShape 
{ 
    public static string commonPath {get;set;} 
    ... add other common functionality .... 
    ... for example, how to load the xml file .... 
    public static XDocument LoadData(string fileName) 
    { 
     ...... 
    } 
} 

那麼你的類從這個基類

public class SteelPipeShape : SteelShape 
{ 
    .... 
} 

得到時，你需要使用祖先類指的是你提到它通過你的類的實例共享的公共變量命名

SteelShape.commonPath; 

所以把所有在一起，你有

void Main() 
{ 
    // Set the path once and for all 
    SteelShape.commonPath = @"d:\temp"; 

    SteelBeamShape myBeam1 = new SteelBeamShape("W6x9"); 
    SteelBeamShape myBeam2 = new SteelBeamShape("W10x22"); 
    SteelPipeShape myPipe1 = new SteelPipeShape("10odx.375wall"); 
    SteelPipeShape myPipe2 = new SteelPipeShape("24odx.750wall"); 
} 

public abstract class SteelShape 
{ 
    public static string commonPath {get;set;} 
    public static XDocument LoadData(string fileName) 
    { 
     ...... 
    } 
} 

public class SteelPipeShape : SteelShape 
{ 
    public SteelBeamShape(string SteelBeamNominalValue) 
    { 
     this.xmlDataPath = SteelShape.commonPath; 
     XDocument doc = SteelShape.LoadData("steelbeamshape.xml"); 
     // do stuff .... 
    } 
} 
public class SteelBeamShape : SteelShape 
{ 
    public SteelPipeShape(string SteelPipeNominalValue) 
    { 
     // look up some properties base on nominal value in XML tables 
     this.xmlDataPath = SteelShape.commonPath; 
     XDocument doc = SteelShape.LoadData("steelpipeshape.xml"); 

     // do stuff .... 
    } 
} 

Answer 2

您可以通過這樣做從公共基類繼承所有Shape類，並在基類中將公共變量定義爲protected static或public static。

public abstract class BaseShape 
{ 
    public static string mSomeVar = "SomeValue"; 
} 

public class SteelBeamShape : BaseShape 
{ 
    // constructor 
    public SteelBeamShape(string SteelBeamNominalValue) 
    { 
     // look up some properties base on nominal value in XML tables 
     this.xmlDataPath = this.mSomeVar; 

     // do stuff .... 
    } 
} 

public class SteelPipeShape : BaseShape 
{ 
    // constructor 
    public SteelPipeShape(string SteelPipeNominalValue) 
    { 
     // look up some properties base on nominal value in XML tables 
     this.xmlDataPath = this.mSomeVar; 

     // do stuff .... 
    }  
} 

Answer 3

public class Lib 
{ 
    private static string _commonVarialble; 

    public static string CommonVarialble 
    { 
     get { return _commonVarialble; } 
     set { _commonVarialble = value; } 
    } 

    public class SteelBeamShape 
    { 
     // constructor 
     public SteelBeamShape(string steelBeamNominalValue) 
     { 
      // look up some properties base on nominal value in XML tables 
      this.xmlDataPath = CommonVarialble; 

      // do stuff .... 
     } 
    } 
} 

現在，您可以設置CommonVarialble您的類庫外

Answer 4

我會考慮先加載XML數據，然後既可以通過構造函數或類中的方法進行實際發送數據工作。

否則，你可能在你的類中做了基本相同的事情（加載數據，查找XML數據等）中的代碼重複。