I'm engaged in a C# learning process and it is going well so far. I however just now hit my first "say what?" moment.
The DataTable offers random row access to its Rows collection, not only through typical collections behavior, but also through DataTable.Select. However I cannot seem to be able to tie this ability to DataRow.Delete. So far this is what it seems I need to do in order to conditionally delete one or more rows from a table.
int max = someDataTable.Rows.Count - 1;
for(int i = max; i >= 0; --i)
{
if((int)someDataTable.Rows[i].ItemArray[0] == someValue)
{
someDataTable.Rows[i].BeginEdit();
someDataTable.Rows[i].Delete();
}
else
break;
}
someDataTable.AcceptChanges();
But I'm not happy with this code. Neither I'm convinced. I must be missing something. Am I really forced to hit the Rows collection sequentially if I need to delete one or more rows conditionally?
(don't mind the inverted for. I'm deleting from the end of the datatable. So it's ok)
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delete-row
I don't have a windows box handy to try this but I think you can use a DataView and do something like so:
DataView view = new DataView(ds.Tables["MyTable"]);
view.RowFilter = "MyValue = 42"; // MyValue here is a column name
// Delete these rows.
foreach (DataRowView row in view)
{
row.Delete();
}
I haven't tested this, though. You might give it a try.
Here's a one-liner using LINQ and avoiding any run-time evaluation of select strings:
someDataTable.Rows.Cast<DataRow>().Where(
r => r.ItemArray[0] == someValue).ToList().ForEach(r => r.Delete());
Extension method based on Linq
public static void DeleteRows(this DataTable dt, Func<DataRow, bool> predicate)
{
foreach (var row in dt.Rows.Cast<DataRow>().Where(predicate).ToList())
row.Delete();
}
Then use:
DataTable dt = GetSomeData();
dt.DeleteRows(r => r.Field<double>("Amount") > 123.12 && r.Field<string>("ABC") == "XYZ");
Source: Stackoverflow.com