c# dataTable 合并两个列到一个新列中的简单实例

public static datatable unitedatatablecolumns(datatable dt, string newcolumnname, string columnname1, string columnname2)
        {
            //汇总的表达式
            string expression = "";                            
            expression = string.format("{0}+'('+{1}+')'", columnname1, columnname2);          
            //增加汇总列
            system.type mydatatype = system.type.gettype("system.string");
            datacolumn dccol = new datacolumn(newcolumnname, mydatatype, expression, mappingtype.attribute);
            //增加合并列
            dt.columns.add(dccol);
            return dt;
        }