Modifying DataTables C#

Question

I have a list of data in a data table, I also have a button that when clicked Will Show the Rows that have been completed in the last week.

However, I cant get the table to update after the modifications for some reason

I get the date of 7 days ago, and for every row that has a completed date greater than it in the source DataTable, I delete that row. That should leave me with only rows completed in the last week, but for some reason every row remains after my method is done. Can anyone spot a problem here?

Thanks in advance for any help!

protected void btnShowLastWeek_OnClick(Object sender, EventArgs e)
    {
        DateTime current = DateTime.Today;
        DateTime lastWeek = current.AddDays(-7);

        DataTable temp = compDV.Table;

        for(int i = 0; i < temp.Rows.Count; i ++)
        {
            DateTime completed = (DateTime)temp.Rows[i]["DateCompleted"];

            if (completed.CompareTo(lastWeek.Date) <= 0)
            {
                temp.Rows.RemoveAt(i);
            }
        }

        dgCompletedRequests.DataSource = temp;
        dgCompletedRequests.DataBind();
    }

You need to loop over the table backwards, or you'll end up skipping some indices. — SLaks
– SLaks, Commented May 11, 2011 at 20:49
What happens if you step through the method in the debugger? — SLaks
– SLaks, Commented May 11, 2011 at 20:50

SLaks · Accepted Answer · 2011-05-11 20:58:22Z

4

You should bind to a DataView instead:

dgCompletedRequests.DataSource =
    new DataView(compDV.Table, "DateCompleted > #" + lastWeek + "#");

answered May 11, 2011 at 20:58

SLaks

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Anthony Pegram · Accepted Answer · 2011-05-11 21:02:55Z

2

I would follow SLaks' advice from the comments, but when it comes down to it, I would also consider punting and just rewrite the code to query the datatable without modifying the original.

dgCompletedRequests.DataSource = 
      temp.AsEnumerable()
          .Where(row => row.Field<Datetime>("DateCompleted") >= lastWeek)
          .AsDataView(); // or .CopyToDataTable(); if you need it

edited May 11, 2011 at 21:02

answered May 11, 2011 at 20:52

Anthony Pegram

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4 Comments

SLaks Over a year ago

Except that that won't bind correctly. blog.slaks.net/2011/01/binding-to-lists-of-datarows.html

Anthony Pegram Over a year ago

@SLaks, interesting, and it makes sense.

SLaks Over a year ago

AsDataView() would be faster.

korymiller Over a year ago

Thank you Anthony and SLaks! You both have been very helpful!

Rockdocta · Accepted Answer · 2011-05-11 20:50:52Z

0

Was dgCompletedRequests.DataSource already set before this code executes? I'm not sure if this will work for you but it has for me in the past, you might give this a try. Set your dgCompletedRequests.DataSource = null; then set it to temp after. Somehow I think this will "reset" the databinding.

answered May 11, 2011 at 20:50

Rockdocta

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