Question

我有方法readExcelFile（），它采用参数和泛型类型，其中泛型类型是类，所以想法是给这个方法需要参数来读取excel文件，我得到具有excel记录的对象列表。

上面的状态正常，但我还需要定义接口

public interface IProcessExcel 
{
    IList<T> ReadExcelFile(string filePath, int readExcelRowFrom, int headerRow);  
}

并在上面的代码中我收到错误

 The Type or namespace T could not be found(missing directive or assembly )

实施代码

 public class ProcessExcel<T>: IProcessExcel where T: class
{
    private static Excel.Application xlApp;
    private static Excel.Workbook xlWorkbook;
    private static Excel.Worksheet xlWorkSheet;
    private static Excel.Range xlRange;
    private string GivenFilePath = string.Empty;        
    private IList<string> ExcelFileExtensionList = new string[] { ".xls", ".xlsx", ".xlsm", ".xltx", ".xltm" };
    private T newObject;
    List<T> ExcelRecordList = new List<T>();

    public ProcessExcel()
    {
    }


    public IList<T> ReadExcelFile(string filePath, int readExcelRowFrom, int headerRow) 
    {
        this.FilePath = filePath;
        this.ReadExcelRowFrom = readExcelRowFrom;
        this.HeaderRow = headerRow;
        this.ReferenceClass = typeof(T);
        this.ValidateExcelFile();
         this.ProcessReadExcelFile();

        return ReadExcelFile;
    }

Answer 1

您还需要定义通用接口

public interface IProcessExcel<T> where T:class
{
    IList<T> ReadExcelFile(string filePath, int readExcelRowFrom, int headerRow);  
}

编译器不知道如何稍后确定T。

然后，这个类将被定义为：

public class ProcessExcel<T>: IProcessExcel<T> where T: class

Answer 2

您需要在接口和类中正确实现通用方法像这样：

public interface IProcessExcel { IList<T> ReadExcelFile<T>(string filePath, int readExcelRowFrom, int headerRow); }

请注意＆＃39; T＆＃39;在方法名称之后。

如何在Interface中定义IList <t>

2 个答案: