DataTable字符串类型的数字，按照数字类型排序

protected void Page_Load(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Name");
        dt.Columns.Add("Age");//因为是字符串，所以排序不对
        dt.Rows.Add("小明", "21");
        dt.Rows.Add("小张", "10");
        dt.Rows.Add("小红", "9");
        dt.Rows.Add("小伟", "7");
        dt.Rows.Add("小美", "3");
        dt.DefaultView.Sort = "Age ASC";
        dt = dt.DefaultView.ToTable();

        foreach (DataRow s in dt.Rows)
        {
            Response.Write(s["Age"].ToString() + "--" + s["Name"].ToString() + "<br/>");
        }
        Response.Write("------------------1----------------<br/>");

 
        #region 方法1:将年龄补齐为2位，然后再进行排序，但是实际不应该有0(仅作参考)
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            dt.Rows[i]["Age"] = dt.Rows[i]["Age"].ToString().PadLeft(2, '0');
        }
        dt.DefaultView.Sort = "Age ASC";

        dt = dt.DefaultView.ToTable();

        foreach (DataRow s in dt.Rows)
        {
            Response.Write(s["Age"].ToString() + "--" + s["Name"].ToString() + "<br/>");
        }
        #endregion

        Response.Write("------------------2----------------<br/>");

        #region 方法2:创建新的DataTable，将Age类型变更为int类型
        DataTable dtNew = dt.Clone();
        dtNew.Columns["Age"].DataType = typeof(int);//指定Age为Int类型
        foreach (DataRow s in dt.Rows)
        {
            dtNew.ImportRow(s);//导入旧数据
        }

        dtNew.DefaultView.Sort = "Age ASC";
        dtNew = dtNew.DefaultView.ToTable();

        foreach (DataRow s in dtNew.Rows)
        {
            Response.Write(s["Age"].ToString() + "--" + s["Name"].ToString() + "<br/>");
        }
        #endregion

        Response.Write("-----------------3-----------------<br/>");

        #region 方法3:添加一列，主要用于排序
        dt.Columns.Add("AgeLength", typeof(int), "len(Age)");//添加该列时，DataTable列数据即生成

        dt.DefaultView.Sort = "AgeLength,Age ASC";
        dt = dt.DefaultView.ToTable();

        foreach (DataRow s in dt.Rows)
        {
            Response.Write(s["Age"].ToString() + "--" + s["Name"].ToString() + "<br/>");
        }
        #endregion

        Response.Write("-----------------4-----------------<br/>");

        #region 方法4:运用LinQ,将DataTable转换为集合，再调用集合自带的排序方法进行排序
        foreach (DataRow s in dt.Rows.Cast<DataRow>().OrderBy(r => int.Parse(r["Age"].ToString())))
        {
            Response.Write(s["Age"].ToString() + "--" + s["Name"].ToString() + "<br/>");
        }
        #endregion
    }