DataTable转数组和数组转字符串
DataTable转数组：
string[] array=Array.ConvertAll<DataRow, string>(ds.Tables[0].Rows.Cast<DataRow>().ToArray(), r => r["ID"].ToString());
数组转字符串：
string[] array=["1","2","3","4"];
string arrayStr=string.join(',',array);
结果："1,2,3,4"
DataTable转数组：
string[] array=Array.ConvertAll<DataRow, string>(ds.Tables[0].Rows.Cast<DataRow>().ToArray(), r => r["ID"].ToString());
数组转字符串：
string[] array=["1","2","3","4"];
string arrayStr=string.join(',',array);
结果："1,2,3,4"