Question

我有一个数据表，其中以月份为最后一列。我需要打印月份= CurrentMonth的所有行。例如，本月为3月，下个月为4月，等等。

使用下面的示例数据-如何在SS = CurrentMonth的所有行上打印CN和SS？

我想打印到控制台...即Console.PrintLine();

static void Main(string[] args) 
{
  DataTable dtData = new DataTable();
  dtData.Columns.Add("CN", typeof(string));
  dtData.Columns.Add("AN", typeof(string));
  dtData.Columns.Add("SN", typeof(string));
  dtData.Columns.Add("CE", typeof(string));
  dtData.Columns.Add("TSD", typeof(DateTime));
  dtData.Columns.Add("TSC", typeof(DateTime));
  dtData.Columns.Add("T1S", typeof(DateTime));
  dtData.Columns.Add("T1C", typeof(DateTime));
  dtData.Columns.Add("T2S", typeof(DateTime));
  dtData.Columns.Add("T2C", typeof(DateTime));
  dtData.Columns.Add("SS", typeof(string));

  dtData.Rows.Add("1111", "TestSN", "email", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "March");
  dtData.Rows.Add("2222", "TestSN1", "email1", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "July");
  dtData.Rows.Add("3333", "TestSN2", "email2", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "January");
  dtData.Rows.Add("4444", "TestSN3", "email3", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "April");
  dtData.Rows.Add("5555", "TestSN4", "email4", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "October");
  dtData.Rows.Add("6666", "TestSN5", "email5", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "December");
  dtData.Rows.Add("7777", "TestSN6", "email6", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "March");
}

Answer 1

您可以使用DataTable的Select方法仅选择SS列等于本月的行。

var allRows = dt.Select($"SS='{DateTime.Now.ToString("MMMM", CultureInfo.InvariantCulture)}'");
            foreach(var r in allRows)
            {
                Console.WriteLine($"{r["CN"].ToString()}, {r["SS"].ToString()}");
            }

输出：

1111, March
7777, March

此外，上面的代码无法编译。看起来应该删除代码中的这一行：

dtData.Columns.Add("CE", typeof(string));

Answer 2

类似这样的东西：

foreach (DataRow r in dtData.Rows)
{
    if (r["SS"].ToString() == DateTime.Now.ToString("MMMM"))
    {
        Console.WriteLine(r["CN"].ToString() + r["SS"].ToString());
    }
}

Answer 3

您需要的是对数据的简单选择查询：

    string expression = $"SS = '{DateTime.Now.ToString("MMMM")}'";
    var filteredData = dtData.Select(expression);
    foreach(var item in filteredData)
    {
        Console.WriteLine($"CN: {item["CN"]}, SS: {item["SS"]}");
    }

顺便说一句，您的示例还有另一个问题，您忘记了字符串列为4，而在行中插入了3个字符串：

    dtData.Rows.Add("1111", "TestSN",  "email",  "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "March");
    dtData.Rows.Add("2222", "TestSN1", "email1", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "July");
    dtData.Rows.Add("3333", "TestSN2", "email2", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "January");
    dtData.Rows.Add("4444", "TestSN3", "email3", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "April");
    dtData.Rows.Add("5555", "TestSN4", "email4", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "October");
    dtData.Rows.Add("6666", "TestSN5", "email5", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "December");
    dtData.Rows.Add("7777", "TestSN6", "email6", "CE", DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, DateTime.MinValue, "March");

C＃控制台应用程序将打印当前月份的数据

3 个答案: