使用其他類的類字段

Question

我對C＃和OOP相當陌生，請耐心等待。

我有兩個班，不同的命名空間：

namespace Class1 

public class class1 
{ 
public double x; 
public double y; 
} 

... 

namespace Class2 

public class class2 
{ 
public double z = x + 5; 
} 

我創建了一個項目，稱爲插件，並有一個按鈕的形式。該按鈕將添加x，y和z。我的問題是：

如何在class2中使用字段x以及如何在按鈕單擊事件下使用字段x，y和z？

Answer 1

你不使用類字段（除非它們是靜態的，但在你的情況下它們不是），但是對象字段。這裏有一個如何實現你想要的例子。

public class1 { 
    public double Radius; 

    // Function to calculate the area 
    public double Area(double Rad) { 
    this.Radius = Rad; 
    return Math.PI * Math.Pow(this.Radius, 2); 
    } 

} 

public class2 { 
    public double Depth; 

    // Function to calculate the volume of a cylinder 
    public double Volume(double Rad, double Dep) { 
    this.Depth = Dep; 

    // Create an instance of Class1 and use it to calculate the Volume 
    var Obj1 = new class1(); 
    return Obj1.Area(Rad) * this.Depth; 
    } 
} 

如何使用上面的按鈕單擊事件

// Let's calculate an Area from a Radius 
double SomeRadius = 1.234; 

MyObj1 = new class1(); 
double Area = MyObj1.Area(SomeRadius); 

double StoredRadius = MyObj1.Radius; // This will give you back the Radius stored by MyObj1, which is the same you passed to Area() function 

// Now let's calculate a Volume, using the Radius we indicated earlier and a Depth 
double SomeDepth = 4.567; 
MyObj2 = new class2(); 
double Volume = MyObj2.Volume(SomeRadius, SomeDepth); 

double StoredDepth = MyObj2.Depth; // This will give you back the Depth stored by MyObj2, which is the same you passed to Volume() function 

Answer 2

你可能會希望有class2採取在其構造class1一個實例：

public class class2 
{ 
private readonly class1 _c1; 
public class2(class1 c1) { _c1 = c1; } 

public double z = _c1.x + 5; 
} 

由於對於如何使用字段x，y和z以及表單中的按鈕單擊事件，您只需訪問class1和class2實例上的公共字段x，y和z：

protected void button_click(){ 
class1 c1 = new class1(); 
c1.x = 10; 
c1.y = 20; 
class2 c2 = new class2(c1); 

//do something with c1 and c2 now... 
Console.WriteLine("{0} {1} {2}", c1.x.ToString(), c1.y.ToString(), c2.z.ToString()); 
} 

讓我知道如果我誤解了你想要做的事情。希望這可以幫助！

Answer 3

在class2你需要一個對象從class1

public class class2 
{ 
class1 class1 = new class1(); 

public double z = class1.x + 5; 
} 

Answer 4

這裏每個人給你正確的答案訪問的領域，但在地區和您在程序上接近問題的體積的情況下，不是OO的方式。這是一個示例，向您展示如何訪問內部字段以及用OO的方式來處理這類問題：

public abstract class Shape 
{ 
    public abstract double Area(); 
    public abstract double Perimeter(); 
} 

public class Circle : Shape 
{ 
    public double Radius; 

    public override double Perimeter() 
    { 
     return 2 * Radius * Math.PI; 
    } 

    public override double Area() 
    { 
     return Radius * Radius * Math.PI; 
    } 
} 

public class Square : Shape 
{ 
    public double Side; 

    public override double Perimeter() 
    { 
     return Side * 4; 
    } 

    public override double Area() 
    { 
     return Side * Side; 
    } 
} 

public abstract class Solid 
{ 
    public abstract double Volume(); 
} 

public abstract class CircleBaseSolid : Solid 
{ 
    protected Circle Base = new Circle(); 

    public double Radius 
    { 
     get { return Base.Radius; } 
     set { Base.Radius = value; } 
    } 

    public double Height; 
} 

public class Cylinder : CircleBaseSolid 
{ 
    public override double Volume() 
    { 
     return Base.Area() * Height; 
    } 
} 

public class Cone : CircleBaseSolid 
{ 
    public override double Volume() 
    { 
     return Base.Area() * Height/3; 
    } 
} 

public abstract class SquareBaseSolid : Solid 
{ 
    protected Square Base = new Square(); 

    public double Side 
    { 
     get { return Base.Side; } 
     set { Base.Side = value; } 
    } 

    public double Height; 
} 

public class SquareParallelepiped : SquareBaseSolid 
{ 
    public override double Volume() 
    { 
     return Base.Area() * Height; 
    } 
} 

public class SquarePyramid : SquareBaseSolid 
{ 
    public override double Volume() 
    { 
     return Base.Area() * Height/3; 
    } 
}