How do you Sort a DataTable given column and direction?

I need to resort, in memory, a DataTable based on a column and direction that are coming from a GridView. The function needs to look like this:

public static DataTable resort(DataTable dt, string colName, string direction)
{
    DataTable dtOut = null;

    ....
}

I need help filling in this function. I think I can use a Select statement but I am not sure how. I can't click on Comments because of this browser but you can show me an in-place or new DataTable solution, either one. For the people showing me pointers, please, I need a coded function similar to the one prototyped.

How about:

// ds.Tables[0].DefaultView.Sort="au_fname DESC";
   public static void Resort(ref DataTable dt, string colName, string direction)
   {
        string sortExpression = string.Format("{0} {1}", colName, direction);
        dt.DefaultView.Sort = sortExpression;
   }

I assume "direction" is "ASC" or "DESC" and dt contains a column named "colName"

public static DataTable resort(DataTable dt, string colName, string direction)
{
    DataTable dtOut = null;
    dt.DefaultView.Sort = colName + " " + direction;
    dtOut = dt.DefaultView.ToTable();
    return dtOut;
}

OR without creating dtOut

public static DataTable resort(DataTable dt, string colName, string direction)
{
    dt.DefaultView.Sort = colName + " " + direction;
    dt = dt.DefaultView.ToTable();
    return dt;
}

If you've only got one DataView, you can sort using that instead:

table.DefaultView.Sort = "columnName asc";

Haven't tried it, but I guess you can do this with any number of DataViews, as long as you reference the right one.

Actually got the same problem. For me worked this easy way:

Adding the data to a Datatable and sort it:

dt.DefaultView.Sort = "columnname";
dt = dt.DefaultView.ToTable();

DataTables have an overloaded Select method that you can you to do this. See here: http://msdn.microsoft.com/en-us/library/way3dy9w.aspx

But the return val of the Select call is not a DataTable but an array of RowData objects. If you want to return a DataTable from your function you will have to build it from scratch based on that data array. Here is a post that addresses and provides a sample for both issues: http://social.msdn.microsoft.com/Forums/en-US/winformsdatacontrols/thread/157a4a0f-1324-4301-9725-3def95de2bf2/

Create a DataView. You cannot sort a DataTable directly, but you can create a DataView from the DataTable and sort that.

Creating: http://msdn.microsoft.com/en-us/library/hy5b8exc.aspx

Sorting: http://msdn.microsoft.com/en-us/library/13wb36xf.aspx

> The following code example creates a view that shows all the products > where the number of units in stock is less than or equal to the > reorder level, sorted first by supplier ID and then by product name.

DataView prodView = new DataView(prodDS.Tables["Products"], "UnitsInStock <= ReorderLevel", "SupplierID, ProductName", DataViewRowState.CurrentRows);

In case you want to sort in more than one direction

  public static void sortOutputTable(ref DataTable output)
        {
            DataView dv = output.DefaultView;
            dv.Sort = "specialCode ASC, otherCode DESC";
            DataTable sortedDT = dv.ToTable();
            output = sortedDT;
        }