请帮助我理解以下内容:
public sealed class SqlConnection : DbConnection, ICloneable {...}
在上面的课上我有两个疑惑
在 C# 中,多重继承是不可能的(我们可以通过接口(interface)实现)。但是这里的 DBconnection 不是一个接口(interface)那么它是如何支持多重继承的呢?
Iclonable 是一个接口(interface)。它有一个名为 object Clone() 的方法。但是在 Sqlconnection 类中没有实现该方法。怎么可能?
请帮助我理解这一点
最佳答案
这里没有多重继承。您可以继承一个类并实现多个接口(interface)。这里,
DBConnection
是一个类,IClonable
是一个interface
IClonable 声明为
Explicit Interface
,这意味着您不能直接从类实例访问它,而必须显式转换为接口(interface)类型
示例
interface IDimensions
{
float Length();
float Width();
}
class Box : IDimensions
{
float lengthInches;
float widthInches;
public Box(float length, float width)
{
lengthInches = length;
widthInches = width;
}
// Explicit interface member implementation:
float IDimensions.Length()
{
return lengthInches;
}
// Explicit interface member implementation:
float IDimensions.Width()
{
return widthInches;
}
public static void Main()
{
// Declare a class instance "myBox":
Box myBox = new Box(30.0f, 20.0f);
// Declare an interface instance "myDimensions":
IDimensions myDimensions = (IDimensions) myBox;
// Print out the dimensions of the box:
/* The following commented lines would produce compilation
errors because they try to access an explicitly implemented
interface member from a class instance: */
//System.Console.WriteLine("Length: {0}", myBox.Length());
//System.Console.WriteLine("Width: {0}", myBox.Width());
/* Print out the dimensions of the box by calling the methods
from an instance of the interface: */
System.Console.WriteLine("Length: {0}", myDimensions.Length());
System.Console.WriteLine("Width: {0}", myDimensions.Width());
}
}
关于c# - 公共(public)密封类 SqlConnection : DbConnection, ICloneable,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23843786/