如何在此C#程序中打印列名？

你需要循环loadDT.Columns,像这样:

foreach (DataColumn column in loadDT.Columns)
{
    Console.Write("Item: ");
    Console.Write(column.ColumnName);
    Console.Write(" ");
    Console.WriteLine(row[column]);
}

foreach (DataRow row in dt.Rows)
{
    foreach (DataColumn column in dt.Columns)
    {
        ColumnName = column.ColumnName;
        ColumnData = row[column].ToString();
    }
}