c# - 如何从 Datagrid 中的选择列创建 CSV？

Question

 if (!Directory.Exists("C:\\VIES"))
        {
            Directory.CreateDirectory("C:\\VIES");
        }
        dgRecords1.SelectAllCells();
        dgRecords1.ClipboardCopyMode = DataGridClipboardCopyMode.IncludeHeader;

        ApplicationCommands.Copy.Execute(null, dgRecords1);
        dgRecords1.UnselectAllCells();
        String result = (string)Clipboard.GetData(DataFormats.CommaSeparatedValue);
        try
        {
            StreamWriter sw = new StreamWriter("C:\\VIES\\VIESReport.CSV", false);
            sw.WriteLine(result);
            sw.Close();
            Process.Start("C:\\VIES\\VIESReport.CSV");
        }

在上面的代码中，我选择了数据网格中的所有记录以及标题并将其写入 csv 文件。我需要做的是我只需要两列在 csv 中。有没有办法做到这一点？

Answer 1

您可以使用以下代码将数据表转换为 csv。该代码非常灵活，您可以更改列名并选择列数。

要导出到 csv，您需要调用它

ExportFile.ExportCSV(dt, "id,name", "Product ID,Name","order.csv");

类文件如下

public class ExporFile
{
    /// <summary>
    /// Export to CSV
    /// </summary>
    /// <param name="exportTable">Export table</param>
    /// <param name="showColumns">Columns needs to show in CSV</param>
    /// <param name="changedColumnName">Changed Column Names in CSV</param>
    /// <param name="fileName">File Name</param>
    public static void ExportCSV(DataTable exportTable, string showColumns, string changedColumnName, string fileName)
    {
        DataTable filterTable = FilterColumn(exportTable, showColumns, changedColumnName);
        string dataCSV = DataTable2CSV(filterTable, "\t", "\"");
        dataCSV = System.Web.HttpContext.Current.Server.HtmlDecode(dataCSV);
        System.Web.HttpContext.Current.Response.Charset = "";
        System.Web.HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Unicode;
        System.Web.HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
        System.Web.HttpContext.Current.Response.Write(dataCSV);
        System.Web.HttpContext.Current.Response.Flush();
        try
        {
            System.Web.HttpContext.Current.Response.End();
        }
        catch { };
    }

    /// <summary>
    /// Filter Columns
    /// </summary>
    /// <param name="exportTable"></param>
    /// <param name="showColumns"></param>
    /// <param name="changedColumnName"></param>
    /// <returns></returns>
    private static DataTable FilterColumn(DataTable exportTable, string showColumns, string changedColumnName)
    {
        DataView filterDataView = exportTable.DefaultView;
        //filterDataView.Sort = "AutoID";
        DataTable filterTable = filterDataView.ToTable(false, showColumns.Split(','));
        return ChangedExportDataColumnName(filterTable, changedColumnName);
    }

    /// <summary>
    /// Changed Column Datatable
    /// </summary>
    /// <param name="filterTable"></param>
    /// <param name="changedColumnName"></param>
    /// <returns></returns>
    private static DataTable ChangedExportDataColumnName(DataTable filterTable, string changedColumnName)
    {
        string[] changedNames = changedColumnName.Split(',');

        for (int i = 0; i < changedNames.Length; i++)
        {
            if (!String.IsNullOrEmpty(changedNames[i]))
            {
                filterTable.Columns[i].ColumnName = changedNames[i];
            }
        }
        return filterTable;
    }

    /// <summary>
    /// Returns a CSV string corresponding to a datatable. However the separator can be defined and hence it can be any string separated value and not only csv.
    /// </summary>
    /// <param name="table">The Datatable</param>
    /// <param name="separator">The value separator</param>
    /// <param name="circumfix">The circumfix to be used to enclose values</param>
    /// <returns></returns>
    private static String DataTable2CSV(DataTable table, string separator, string circumfix)
    {

        StringBuilder builder = new StringBuilder(Convert.ToString((char)65279));
        foreach (DataColumn col in table.Columns)
        {
            builder.Append(col.ColumnName).Append(separator);
        }
        builder.Remove((builder.Length - separator.Length), separator.Length);
        builder.Append(Environment.NewLine);

        foreach (DataRow row in table.Rows)
        {
            foreach (DataColumn col in table.Columns)
            {
                builder.Append(circumfix).Append(row[col.ColumnName].ToString().Replace("\"", "\"\"")).Append(circumfix).Append(separator);
            }
            builder.Remove((builder.Length - separator.Length), separator.Length);
            builder.Append(Environment.NewLine);
        }
        return builder.ToString();
    }
}