UserControl和继承 [英] UserControl and Inheritance

问题描述

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我有一个UserControl，它有一个类如下所示。此Class a方法称为DrawHistogram

Good Day,

Please your help in

I have a UserControl which have a class as shown below. This Class a method Called DrawHistogram

namespace Prog1
{
	/// <summary>
	/// Summary description for HistogramaDesenat.
	/// </summary>
	public class HistogramControlClass : System.Windows.Forms.UserControl
	{ ......// Codes 

        }
        public void DrawHistogram(long[] Values)
         {
            //Doing calculation 
         }
		
}

另一方面，我有一张以下表格

In other hand, I have a Form with the following

namespace Prog1.ImageHistogram
{
    class HistogramEqualization:PNM, HistogramControlClass
    {
//I need to call DrawHistogram here where I used using and multi base class but 
// Still unable to call it

     }
}

简单地说，我需要从中调用DrawHistogram表单，使用使用和Multibase类但仍然无法调用它。

任何帮助表示赞赏

Simply, I need to call DrawHistogram from the Form, using "using" and Multibase class but still unable to call it.
Any help is appreciated

推荐答案

两件事：



首先，在方法名称中放置一个方法：

Two things:

First, you put a method inside a namespace:

namespace Prog1
{
	/// <summary>
	/// Summary description for HistogramaDesenat.
	/// </summary>
	public class HistogramControlClass : System.Windows.Forms.UserControl
	{ ......// Codes 

        }
        public void DrawHistogram(long[] Values)
         {
            //Doing calculation 
         }		
}

你不能把一个方法放在命名空间里，总是必须把它放在一个类中。



其次， HistogramEqualization 派生自两个cla sses：

You can't put a method inside a namespace, you always have to put it inside a class.

Second, HistogramEqualization derives from two classes:

class HistogramEqualization:PNM, HistogramControlClass

这是不可能的，因为C＃只支持接口的多重继承。如果 PNM 是一个接口，那么在这种情况下可以进行多重继承。如果 PNM 是一个类，那么就不可能。

解决方案

，将 DrawHistogram 方法放在 HistogramControlClass 中：

This is impossible, because C# does only support multiple inheritance for interfaces. If PNM is an interface, then multiple inheritance is possible in this case. If PNM is a class, then it is not possible.

Solution

First, put the DrawHistogram method inside the HistogramControlClass:

namespace Prog1
{
	/// <summary>
	/// Summary description for HistogramaDesenat.
	/// </summary>
	public class HistogramControlClass : System.Windows.Forms.UserControl
	{ ......// Codes 
             public void DrawHistogram(long[] Values)
             {
                //Doing calculation 
             }
        }		
}

然后，解决多重继承问题。仅当 PNM 不 界面时，才需要这样做。一种可能的解决方案是将 PNM 的属性/字段/方法移动到 HistogramControlClass 。



解决这些问题后，您将能够在 HistogramEqualization 中调用 DrawHistogram 。

Then, solve the multiple inheritance problem. This is only necessary if PNM is not an interface. A possible solution is to move the properties/fields/methods of PNM to HistogramControlClass.

After solving these problems, you'll be able to call DrawHistogram in HistogramEqualization.

您的代码片段显示D​​rawHistogram方法不是HistogramControlClass的一部分 - 它在类定义之外。因此，如果您的HistogramControlClass嵌套在不同的类中，那么DrawHistogram是该类的方法，而不是HistogramControlClass。



快速检查说这一切都有效：

Your code fragment shows the DrawHistogram method as not a part of the HistogramControlClass - it is outside the class definition. So if your HistogramControlClass is nested in a different class, then DrawHistogram is a method of that class, not HistogramControlClass.

A quick check says this all works:

public partial class Form1 : Form
    {
    ...
    private void MyMethod()
        {
        HistogramControlClass hcc = new HistogramControlClass();
        hcc.DrawHistogram(new long[10]);
        }
    }
public class HistogramControlClass : UserControl
    {
    public void DrawHistogram(long[] values)
        {
        }
    }
public class HistogramEqualization : HistogramControlClass
    {
    public void MyMethod()
        {
        DrawHistogram(new long[100]);
        }
    }

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