Question

I have a bunch of data tables (In a list), all with 50 columns.

Say I want to build a new data table with columns 20-29 and 40-49.
and then copy all rows from each data table into the new one. but only those selected columns.

DataTable.Merge() will not work since I only want a subset of the columns.

What’s the best way to achieve this goal?

Answer 1

I think simple plain old for loops should do the trick under these conditions

DataTable table = new DataTable();
DataTable existing = listOfTables[0];

for(int i = 20; i < 30; i ++)
{
    table.Columns.Add(existing.Column[i].Name;
    table.Columns.Add(existing.Column[i + 20].Name;
}

foreach(DataTable table in listOfTables)
{
    foreach(DataRow row in table.Rows)
    {
        DataRow newRow = table.NewRecord();
        foreach(Column column in table.Columns)
        {
           newRow[column.Name] = row[column.Name];
        }
        table.Rows.Add(row);
    }
}

Note
I haven’t compiled the code.