Question

我是c＃的新手，我正在尝试将表数据从sqlite 3数据库导出到csv但是日期时间格式在csv中已经改变，sqlite 3中的格式是：

2013-04-16 21:33:42.000

而csv中的日期时间显示为：

16/04/2013 21:33:42,

这是我的代码：

SQLiteConnection m_dbConnection;
//m_dbConnection = new SQLiteConnection("Data Source= C:/Users/IT-Administrator/Desktop/WebMobility.db; Version=3;");

m_dbConnection = new SQLiteConnection("Data source = F:/Explor/final test/WebMobility.db; Version=3;");
m_dbConnection.Open();

SQLiteCommand myCommand = new SQLiteCommand();
myCommand.Connection = m_dbConnection;


myCommand.CommandText = "select CompanyId,`DateTime`,Serial,ShortDeviceId,MatricolaA,Upper(Targa),CommonRoadDescription,RoadCivicNumber,GpsAddress,VerbaliVehicleTypeDescription,VehicleBrandDescription,VehicleModelDescription,CommonColorVehicleDescription,VerbaliRuleOneCode,VerbaliRuleOneDescription,VerbaliClosedNoteDescription,VerbaliRuleOnePoints,VerbaliMissedNotificationDescription  from  VerbaliData";
//myCommand.Connection = myConn;
DataTable data = new DataTable();
SQLiteDataAdapter myAdapter = new SQLiteDataAdapter(myCommand);
//myAdapter.SelectCommand = myCommand;
myAdapter.Fill(data);
dataGridView1.DataSource = data;
this.dataGridView1.Refresh();
if (dataGridView1.RowCount > 0)
{
    string value = "";
    DataGridViewRow dr = new DataGridViewRow();
    StreamWriter swOut = new StreamWriter("F:/Explor/final test/finaltest12.csv");

    //write header rows to csv
    for (int i = 0; i <= dataGridView1.Columns.Count - 1; i++)
    {
        if (i > 0)
        {
            swOut.Write(",");
        }
        swOut.Write(dataGridView1.Columns[i].HeaderText);
    }

    swOut.WriteLine();

    //write DataGridView rows to csv
    for (int j = 0; j <= dataGridView1.Rows.Count - 1; j++)
    {
        if (j > 0)
        {
            swOut.WriteLine();
        }

        dr = dataGridView1.Rows[j];

        for (int i = 0; i <= dataGridView1.Columns.Count - 1; i++)
        {
            if (i > 0)
            {
                swOut.Write(",");
            }

            value = dr.Cells[i].Value.ToString();
            //replace comma's with spaces
            value = value.Replace(',', ' ');
            //replace embedded newlines with spaces
            value = value.Replace(Environment.NewLine, " ");

            swOut.Write(value);
        }
    }
    swOut.Close();
}

m_dbConnection.Close();

Answer 1

DateTime列没有格式。它只是用于显示以特定格式格式化列值的列内容的工具说很明显你需要做同样的事情来在CSV文件上打印你的值。

在内部循环中，检查列是否为日期时间，然后将其值格式化为您的喜欢。

for (int i = 0; i <= dataGridView1.Columns.Count - 1; i++)
{
    if (i > 0)
    {
         swOut.Write(",");
    }
    // Datetime column content transformed  in a formatted string....
    if(i == 1)
       value = Convert.ToDateTime(dr.Cells[i].Value).ToString("yyyy-MM-dd hh:mm:ss.fff");
    else
       ....

编辑如果你的单元格中有空值或空值，那么你需要在尝试转换之前检查它

    // Datetime column content transformed in a formatted string....
    if(i == 1)
    {
       object cellValue = dr.Cells[i].Value;
       value = (cellValue == DBNull.Value ? 
             string.Empty : Convert.ToDateTime(cellValue).ToString("yyyy-MM-dd hh:mm:ss.fff");
    }

这将写一个空列，其中包含日期。这可能是正确与否，具体取决于CSV文件的使用方式。您可以保存预定义值，而不是空字符串。

Answer 2

if (i==1)
   {
    value = dr.Cells[i].Value.ToString();
    if (value!null)
    {
    string dt=DateTime.Parse(value).ToString("yyyy/MM/dd hh:mm:ss");
    swOut.Write(dt);
    }
    ......
    }

导出到csv时日期格式不正确

2 个答案: