请教关于asp.net自动生成编号问题
我做了个留言板,添加记录时想让程序自动生成一个编号,用的datareader,也实现了。不足之处是当数据表里没有记录时会出错。哪位大哥能出个主意怎么解决出错问题?非常感谢
我的代码如下:
//编号自动累加================
//连接数据库
OleDbConnection myconn = Class1.getconn();
myconn.Open();
varneirong = HtmlEncode(varneirong);
//编号自动累加================
OleDbCommand cmm0 = new OleDbCommand("select bianhao from biao order by bianhao desc", myconn);
OleDbDataReader dr = cmm0.ExecuteReader();
if (dr.Read())
{
int mybianhao = Convert.ToInt16(dr["bianhao"])+1;
string varbianhao = mybianhao.ToString();
OleDbCommand cmm = new OleDbCommand("insert into biao(username,bianhao,neirong) values('" + varname + "','" + varbianhao + "','" + varneirong + "')", myconn);
cmm.ExecuteNonQuery();
Response.Write("<script>window.location='edit.aspx'</script>");
}