Question

asp.net(C#)的DropDownList控件怎么数据绑定

求解这段代码的意思，在线等

string ff = "SELECT id=SUBSTRING(a.teaclass,number,CHARINDEX(',',a.teaclass+',',number)-number) FROM tb_Teacher a,master..spt_values WHERE number<=LEN(a.teaclass) AND SUBSTRING(','+a.teaclass,number,1)=',' and a.id='" + zid + "' GROUP BY SUBSTRING(a.teaclass,number,CHARINDEX(',',a.teaclass+',',number)-number) ";
DataTable df = DBUtility.DbHelperSQL.Query(ff).Tables[0];
DataTable dt1 = new DataTable();
dt1.Columns.Add("id");
dt1.Columns.Add("name");
for (int i = 0; i < df.Rows.Count; i++)
{
string sa2 = "select * from tb_Classag where id=" + Convert.ToInt32(df.Rows[i]["id"]);
DataTable ds = DBUtility.DbHelperSQL.Query(sa2).Tables[0];
if (ds.Rows.Count > 0)
{

dt1.Rows.Add(Int32.Parse(ds.Rows[0]["id"].ToString()), ds.Rows[0]["name"]);

}

}
DropDownList3.DataSource = dt1;
DropDownList3.DataTextField = "name"; //文本内容字段
DropDownList3.DataValueField = "id"; //值字段
DropDownList3.DataBind();
string ff = "SELECT
id=SUBSTRING(a.teaclass,number,CHARINDEX(',',a.teaclass+',',number)-number)
FROM tb_Teacher a,master..spt_values WHERE number<=LEN(a.teaclass)
AND SUBSTRING(','+a.teaclass,number,1)=',' and a.id='" + zid + "' GROUP
BY
SUBSTRING(a.teaclass,number,CHARINDEX(',',a.teaclass+',',number)-number)
";

我自己想做的东西是绑定通过personal_customer表里的endcationid字段查找出education表的学历字段，然后显示在DropDownList
控件上，还可以把用户选择的下拉选项内容改变personal_customer表里的endcationid字段值同时改变education表的学历字段值

Answer 1

DataTable df = DBUtility.DbHelperSQL.Query(ff).Tables[0]; //查表tb_Teacher
DataTable dt1 = new DataTable();
dt1.Columns.Add("id");
dt1.Columns.Add("name");
for (int i = 0; i < df.Rows.Count; i++)//遍历所有行，查tb_Classag表中 id＝id

{
string sa2 = "select * from tb_Classag where id=" + Convert.ToInt32(df.Rows[i]["id"]);
DataTable ds = DBUtility.DbHelperSQL.Query(sa2).Tables[0];
if (ds.Rows.Count > 0)//如果查到，添加到dt1
{

dt1.Rows.Add(Int32.Parse(ds.Rows[0]["id"].ToString()), ds.Rows[0]["name"]);

}

}
DropDownList3.DataSource = dt1; //DropDownList3 绑带数据，显示 DropDownList3.DataTextField = "name"; //文本内容字段
DropDownList3.DataValueField = "id"; //值字段
DropDownList3.DataBind();

Answer 2

你这样写绑定不上吗？
查询出来dt 而后循环dt foreach（Datarow dr in dt）
｛
this.ddl.itmes.add(new listitem(dr[].tostring(),dr[].tostring()));// 文本和值
｝

追问

这是公司的师傅给我的例子让我学习，数据库里有很多字段看不懂，这一句，补充在问题上了