How to add a column to a datatble based on for loop value RSS

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  anilr499

  Member

  94 Points

  389 Posts

  How to add a column to a datatble based on for loop value

  Jan 08, 2013 12:42 AM|LINK

  i have 2 for loops in my code....

  for the first for loop when m = 0....i'll get a new column called "COL"
  in my datatable...

  now my problem is when m = 1.... i need another column called "feb" in my datatable

  when my "m" changes my "da" also changes,,,so i get different calculation....

  similarly for m=2...one more column
  similarly for m=3...one more column......till m = 6

  ArrayList projects = new ArrayList();
  DataColumn dc1 = new DataColumn("cal");
  _table.Columns.Add(dc1);

  for (int m = 0; m < _table1.Rows.Count; m++)
  {

  
  int da = (Convert.ToInt16(_table1.Rows[m]["days"]));

  
  for (int i = 0; i < _table.Rows.Count; i++)
  {
  int g;

  
  {
  g = (Convert.ToInt16(_table.Rows[i]["RE"]) * 100) / ((Convert.ToInt16(_table.Rows[i]["HC"]) * da));
  
  }

  projects.Add(g);

  }

  
  for (int k = 0; k < _table.Rows.Count; k++)
  {
  _table.Rows[k][dc1] = projects[k];
  
  }

  
  gvresmgt.DataSource = _table;
  gvresmgt.PageSize = Int16.Parse(ConfigurationManager.AppSettings["GridPageSize"]);
  gvresmgt.DataBind();

  }
  }

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  sarathi125

  Star

  13599 Points

  2691 Posts

  Re: How to add a column to a datatble based on for loop value

  Jan 08, 2013 05:25 AM|LINK

  Hi,

  You can try like the following if you have the column names in a list

  private void button1_Click(object sender, EventArgs e)
          {
              DataTable dt = new DataTable();
              List<String> dtColumns = new List<string>();
              dtColumns.Add("Column1");
              dtColumns.Add("Column2");
              dtColumns.Add("Column3");
              dtColumns.Add("Column4");
              dtColumns.Add("Column5");
              dtColumns.Add("Column6");

              for (int m = 0; m < 6; m++)
              {
                  dt.Columns.Add(dtColumns[m].ToString());
              }
              dt.AcceptChanges();
          }

  Hi,

  Try like the following,

   

  Parthasarathi,
  Remember to click Mark as Answer on the post that helps to others.
  
  My Blog :MyAspSnippets
  • Marked as answer by decker dong - msft on Jan 14, 2013 05:44 AM
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  DonIzzBack

  Member

  39 Points

  70 Posts

  Re: How to add a column to a datatble based on for loop value

  Jan 08, 2013 05:39 AM|LINK

  try by writing new connection string

  Dim str As String = Select '' As column, continue ur further string here.....

  Eg 

  Dim str As String ="Select '' AS column, date_time FROM Calendar

  this will automatically generates new column with name "column" in ut dt.

• • Reply
  

  Decker Dong ...

  All-Star

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  18779 Posts

  Re: How to add a column to a datatble based on for loop value

  Jan 10, 2013 12:56 AM|LINK

  anilr499

  anilr499

  Hi,

  I'm afraid you have to:

  1) Use something like DataTable.Columns.Add(……) to dyanmically add columns.

  2) Then keep your DataTable in memory (because Html is of non-memory), into a ViewState. If necessary, take it out for futher use.