Hello Norman,

This column is actually a column that displays arrow buttons which open a new NDataGridView in a popup to display some additional detailed data for each data row in the main NDataGridView. If you bind a DataSet with two tables which have relation this column will display automatically to be able to display the data from the child DataTable.

Here is an example:

DataSet dataSet = new DataSet();

DataTable mainTable = new DataTable("mainTable");

DataColumn dataColumn1 = new DataColumn();
DataColumn dataColumn2 = new DataColumn();

mainTable.Columns.Add(dataColumn1);
mainTable.Columns.Add(dataColumn2);

for (int i = 0; i < 10; i++)
{
    DataRow row = mainTable.NewRow();
    row[0] = i;
    row[1] = "Row " + i.ToString();
    mainTable.Rows.Add(row);
}

DataTable childTable = new DataTable("childTable");

DataColumn dataColumn3 = new DataColumn();
DataColumn dataColumn4 = new DataColumn();

childTable.Columns.Add(dataColumn3);
childTable.Columns.Add(dataColumn4);

for (int i = 0; i < 10; i++)
{
    for (int j = 0; j < 5; j++)
    {
        DataRow row = childTable.NewRow();
        row[0] = i;
        row[1] = "Child Row " + j.ToString();
        childTable.Rows.Add(row);
    }
}

dataSet.Tables.Add(mainTable);
dataSet.Tables.Add(childTable);

DataRelation dataRelation = new DataRelation("Relation1", mainTable.Columns[0], childTable.Columns[0]);

dataSet.Relations.Add(dataRelation);

nDataGridView1.DataMember = "mainTable";
nDataGridView1.DataSource = dataSet;

I hope this helps.