Reverse a Dataset

[Paez]

Hi there.

Anybody knows if is it possible to reverse a dataset? Lets say, if the
dataSet has 10 rows, row 1 will row 10 and row 10 will be 1 and so on...

Thanks in advance.

Paez

 

[Mark Rae]

Anybody knows if is it possible to reverse a dataset? Lets say, if the
dataSet has 10 rows, row 1 will row 10 and row 10 will be 1 and so on...

I don't think there's anything built-in which would do this...

However, you could certainly walk through the rows in reverse order:

for (int intRow = MyDataSet.Tables[0].Rows.Count - 1; intRow >= 0; intRow--)
{
// do something with MyDataSet.Tables[0].Rows[intRow]
}

 

[Dave Sexton]

Hi Paez,

If you need to sort the DataRows just to display them on a DataGridView via
binding, for example, then just bind to a DataView instead and set the Sort
property. It's much easier and certainly more practical then reordering the
actual DataRows within the DataTable.

// dataTable is an instance of your DataTable
dataTable.DefaultView.Sort = "FirstName DESC";

dataGridView.DataSource = dataTable.DefaultView;

DataView Class
http://msdn2.microsoft.com/en-us/library/system.data.dataview.aspx

You'll need a column to sort on, of course. If you simply need to reverse
the records as they exist in the DataTable then add a new AutoNumber column
to the DataTable and sort by that column.

Data Access in Client and Middle-Tier Programming
How to: Create an Autonumber DataColumn
http://msdn2.microsoft.com/en-gb/library/yctw654b(VS.80).aspx

 

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

Most probably you mean a DataTable, a dataset is mainly a set of Datatables
that are the one that contain the data.

There is nothing like that I'm afraid, the internal structure to hold the
DataRow is "unknow" how it store the elements.

What do you want to do anyway?

You can use a DataView and sort the rows in the order you want pretty
easily.