如何将DataSet转换为DataTable

Question

我正在从SQL表中检索数据,因此我可以在页面上将结果显示为HTML表.稍后我需要能够将该表保存为CSV文件.

到目前为止,我已经找到了如何检索数据并将其填充到数据集中以供显示目的(这完美地工作)......

        string selectQuery = "SELECT Name, ProductNumber, ListPrice FROM Poduction.Product";

        // Establish the connection to the SQL database 
        SqlConnection conn = ConnectionManager.GetConnection();
        conn.Open();

        // Connect to the SQL database using the above query to get all the data from table.
        SqlDataAdapter myCommand = new SqlDataAdapter(selectQuery, conn);

        // Create and fill a DataSet.
        DataSet ds = new DataSet();
        myCommand.Fill(ds);

以及如何使用以下代码将其保存在CSV文件中:http://www.evontech.com/login/topic/1983.html

    private void exportDataTableToCsv(DataTable formattedDataTable, string filename)
    {
       DataTable toExcel = formattedDataTable.Copy();
       HttpContext context = HttpContext.Current;
       context.Response.Clear();

       foreach (DataColumn column in toExcel.Columns)
       {
          context.Response.Write(column.ColumnName + ",");
       }

       context.Response.Write(Environment.NewLine);
       foreach (DataRow row in toExcel.Rows)
       {
          for (int i = 0; i < toExcel.Columns.Count; i++)
          {
             context.Response.Write(row.ToString().Replace(",", string.Empty) + ",");
          }

          context.Response.Write(Environment.NewLine);
       }

       context.Response.ContentType = "text/csv";
       context.Response.AppendHeader("Content-Disposition", "attachment; filename=" + filename + ".csv");
       context.Response.End();
    }

现在我的问题是如何将其转换DataSet为DataTable？我试过这里所描述的方式没有运气:http://www.ezineasp.net/post/ASP-Net-C-sharp-Convert-DataSet-toANNTable.aspx

谁能帮我？

Answer 1

一个DataSet已经包含 DataTables.你可以使用:

DataTable firstTable = dataSet.Tables[0];

或按名称:

DataTable customerTable = dataSet.Tables["Customer"];

请注意,您应该拥有usingSQL代码的语句,以确保正确处理连接:

using (SqlConnection conn = ...)
{
    // Code here...
}

Answer 2

DataSet是DataTables的集合。...您可以从DataSet中获取数据表，如下所示。

//here ds is dataset
DatTable dt = ds.Table[0]; /// table of dataset