Recommendations For Abstract Class Vs Interfaces?
Dec 21, 2010
From the following URL i got some doubts about the Recommendations for using Abstract class vs interfaces
[URL]
1. If you anticipate creating multiple versions of your component, create an abstract class. Abstract classes provide a simple and easy way to version your components. By updating the base class, all inheriting classes are automatically updated with the change. Interfaces, on the other hand, cannot be changed once created. If a new version of an interface is required, you must create a whole new interface. { Is there any example for this t ounderstand throughly ?} If you are designing small, concise bits of functionality, use interfaces. If you are designing large functional units, use an abstract class. If you want to provide common, implemented functionality among all implementations of your component, use an abstract class. Abstract classes allow you to partially implement your class, whereas interfaces contain no implementation for any members. { Is there any example for this t ounderstand throughly?
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I am trying to compile the following code and i am getting the error:
Cannot create instance of abstract class .
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for(int r=0;r<100;r++)
{
objData[r,0] = "ORD" + r.ToString("0000");
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m_objOpt, m_objOpt, m_objOpt, Excel.XlSaveAsAccessMode.xlNoChange,
m_objOpt, m_objOpt, m_objOpt, m_objOpt);
m_objBook.Close(false, m_objOpt, m_objOpt);
m_objExcel.Quit();
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Error 1279 Cannot create an instance of the abstract class or interface 'System.Web.Mvc.FileResult'
[Code]....
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Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser Error Message: Cannot create an abstract class.
Source Error:
Line 150: <providers>
Line 151: <clear/>
Line 152: <add name="NDMSMembershipProvider"
type="CSW.Web.Security.NDMSMemberProvider"/>
Line 153: </providers>
Line 154: </membership>
Source File: C:DevCSW2srcCSW.Webweb.config Line: 152
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