In my case i am passing a sql query and getting data in dataset, but problem occurs when i try to get the rows where ParentId column contain NULL.This is the piece of code.
DataSet ds = GetDataSet("Select ProductId,ProductName,ParentId from ProductTable");
//ds is not blank and it has 2 rows in which ParentId is NULL
DataRow[] Rows = ds.Tables[0].Select("ParentId IS NULL");
But still i am not getting any rows. Need help. Thanx.
Use the strongly typed DataRow extension method Field which also supports nullable types:
IEnumerable<DataRow> rows = ds.Tables[0].AsEnumerable()
.Where(r => !r.Field<int?>("ParentId").HasValue);
Note that i've used Enumerable.Where which is a Linq extension method to filter the table.
If you want an array use ToArray, if you want a new DataTable use CopyToDataTable. If you simply want to enumerate the result use foreach.
foreach(DataRow row in rows)
{
// ...
}
DataColumn is string instead of int(as i've presumed). You have to use .Where(r => r.Field<string>("ParentId")==null) instead.var rowsWithoutParent = dt.AsEnumerable().Where(r => r["ParentId"] == null);
var rowsWithParent = dt.AsEnumerable().Where(r => r["ParentId"] != null);
var rows = ds.Tables[0].AsEnumerable()
.Where(r => r.IsNull("ParentId"));
work for me:
DataTable newDt = dt.AsEnumerable().Where(r => r["column name"] == DBNull.Value).CopyToDataTable();
if equal to null is not work because is return DBNull
Check
ds.Tables.Count
then
ds.Tables[0].Rows.Count
You can access the items like this:
String value = ds.Tables[0].Rows[RowNum][ColNum].ToString();
