Question

public abstract class GeneralDB : IEntity
{
    protected DataTable table;
    protected int currentRow;
    protected string primaryKey;

    public GeneralDB(string tableName, string primaryKey)
    {
        DAL.GetInstance().AddTable(tableName);//bring data from database
        table = DAL.GetInstance().GetTable(tableName);
        this.primaryKey = primaryKey;
        if (IsEmpty())
            currentRow = -1;
        else
            currentRow = 0;
    }
    #region NAVIGATION
    /// <summary>
    /// going first line
    /// </summary>
    public void GoToFirst()
    {
        if (IsEmpty())
            throw new Exception("navigate on empty table");
        currentRow = 0;
    }
    /// <summary>
    /// going to last line
    /// </summary>
    public void GoToLast()
    {
        if (IsEmpty())
            throw new Exception("navigate on empty table");
        currentRow = table.Rows.Count - 1;
    }
    /// <summary>
    /// go next line if in the end go back to first
    /// </summary>
    public void MoveNext()
    {
        if (IsEmpty())
            throw new Exception("navigate on empty table");
        currentRow = (currentRow + 1) % table.Rows.Count;
    }
    /// <summary>
    /// moves to the previous object. If reaches the beginning, goes back
    /// to the end
    /// </summary>
    public void MovePrev()
    {
        if (IsEmpty())
            throw new Exception("navigate on empty table");
        if (this.currentRow == 0)
            currentRow = table.Rows.Count - 1;
        else
            --currentRow;
    }
    /// <summary>
    /// search obj by its key
    /// </summary>
    /// <param name="key">the key being looked for</param>
    /// <returns>true if found and false if no such row  exists</returns>
    public bool Find(object key)
    {
        int r = 0;
        foreach (DataRow dr in table.Rows)
        {
            if (dr[primaryKey].Equals(key))
            {
                currentRow = r;
                return true;
            }
            else
                r++;
        }
        return false;
    }
    /// <summary>
    /// return current row
    /// </summary>
    /// <returns>Data Row of current row</returns>
    protected DataRow GetThisRow()
    {
        return table.Rows[currentRow];
    }
    #endregion
    #region GENERAL OPERATIONS
    /// <summary>
    /// return num of lines
    /// </summary>
    /// <returns>number of rows</returns>
    public int Size()
    {
        return table.Rows.Count;
    }
    /// <summary>
    /// check if table is empty
    /// </summary>
    /// <returns> true if empty, false if not empty</returns>
    public bool IsEmpty()
    {
        return table.Rows.Count == 0;
    }
    public virtual void Save()
    {
        DAL.GetInstance().Update(table.TableName);
    }
    #endregion
    public DataRow[] Filter(string filterString)
    {
        if (filterString.Trim().Length == 0)
            return table.Select();
        return table.Select(filterString);
    }
    #region CRUD
    public void Add(IEntity obj)
    {
        DataRow dr = table.NewRow();
        obj.Populate(dr);
        table.Rows.Add(dr);
        Find(dr[primaryKey]);
    }
    public void UpdateRow(IEntity obj)
    {
        DataRow dr = GetThisRow();
        obj.Populate(dr);
    }
    public void UpdateRowWithStock(IEntity obj)
    {
        obj.PopulateStock(table.Rows[currentRow]);
    }
    public virtual void DeleteCurrentRow()
    {
        string sqlString = "Delete from " + table.TableName + " where " + primaryKey + " = " + table.Rows[currentRow][primaryKey].ToString();
        DAL.GetInstance().ExecuteNonQuery(sqlString);
        MoveNext();
        object key = table.Rows[currentRow][primaryKey];
        MovePrev();
        table.Rows.Remove(GetThisRow());
        if (!Find(key))
            currentRow = -1;
    }
    #endregion
    public abstract object GetCurrentRow();
    public string GetNameType() { return table.TableName; }
    public abstract void Populate(DataRow dr);
}
}

我想知道如何解决这个错误，因为写这个没有帮助：它告诉我在generaldb中添加这个public void populatestock（datarow dr），我不明白我应该在那里写什么....
它在这一行中给我一个错误：" throw new NotImplementedException(); "
它告诉我："The method or operation is not implemented."

无论如何，任何人都可以帮我处理这个错误：

" Error1 'MatankProj.DB.GeneralDB' does not implement interface  
  member'MatankProj.Entities.IEntity.PopulateStock(System.Data.DataRow)' "

Answer 1

首先，您应该参考接口MatankProj.Entities.IEntity的文档。在那里，您应该能够收集信息，实施PopulateStock(System.Data.Row)的意图。其次，你已经谈过Visual Studio（我假设）给你错误throw new NotImplementedException();。实际上，这不是错误。您似乎试图通过单击从IEntity实施成员之类的内容来尝试自动实现缺少的成员。然后Visual Studio总是做这样的事情：

public void PopulateStock(System.Data.DataRow dataRow)
{
    throw new NotImplementedException();
}

...因为VS希望您用自己的代码替换throw new NotImplementedException();。

既然你说它“告诉你”方法或操作没有实现。，该方法至少执行一次，因此你应该注意这一点。如果您能够找到MatankProj.Entities.IEntity的另一个实现，请查看该实现。

错误1＆＃39; MatankProj.DB.GeneralDB＆＃39;没有实现接口成员＆＃39; MatankProj.Entities.IEntity.PopulateStock（System.Data.DataRow）＆＃39;

1 个答案: