c# 如何返回某张表的所有字段名哦～～～～

// 定义必要的变量
private SqlConnection sqlConn;
private SqlDataAdapter sqlDA1;
private SqlDataAdapter sqlDA2;
private SqlCommand sqlComm;
private System.Data.SqlClient.SqlDataReader dr;

//初始化变量
sqlConn.ConnectionString="字符串"
sqlConn.Open();
sqlComm.CommandText="select * from 表名";
sqlComm.CommandType=CommandType.Text;
sqlComm.Connection=sqlConn;
dr=sqlComm1.ExecuteReader();

//取字段
string s;
for(int i=0;i<=dr.FieldCount-1;i++)
{
s+=dr.GetName(i);//此方法返回字段名；
}

SqlConnection con=new SqlConnection("server=.;uid=sa;pwd=sasa;database=pubs");
con.Open();
SqlCommand cmd=new SqlCommand("select * from jobs",con);
SqlDataReader sdr=cmd.ExecuteReader();
for(int i=0;i<sdr.FieldCount;i++)