Question

dropdownlist后台代码 和数据表编写C#.net

if (!IsPostBack)
{
string cnnstr = "server=(local);database=DK;uid=anqingsong;pwd=897577";
SqlConnection conn = new SqlConnection(cnnstr);
conn.Open();
string sql = "select LareaID,LareaName from larea ";
SqlDataAdapter da = new SqlDataAdapter(sql, conn);
DataSet ds = new DataSet();
da.Fill(ds, "larea");
conn.Close();
DropDownList7.DataSource = ds;

DropDownList7.DataValueField = "LareaID";
DropDownList7.DataTextField = "LareaName";
DropDownList7.DataBind();
}

}
protected void DropDownList7_SelectedIndexChanged(object sender, EventArgs e)
{

string cnnstr = "server=(local);database=DK;uid=anqingsong;pwd=897577";
SqlConnection conn = new SqlConnection(cnnstr);
conn.Open();
string sql = "select AreaID,AreaName from area ";
SqlDataAdapter da = new SqlDataAdapter(sql, conn);
DataSet ds = new DataSet();
da.Fill(ds, "area");
conn.Close();

DropDownList8.DataSource = ds;
DropDownList8.DataValueField = "AreaID";
DropDownList8.DataTextField = "AreaName";
DropDownList8.DataBind();
}

你们看看我这个后台代码有错吗 为什么我选择dropdownlist7中的某个值的时候dropdownlist8把所有的值都列出来，而不是对应的值 如果不是 还有可能是哪出错 数据表会不会有错
DropDownList8.DataSource = ds;

这句上面少打一句string LareaID=DropdownList7.SelectedValue;

Answer 1

change事件的查询sql没有按ddl7的值过滤
string sql = "select AreaID,AreaName from area "; // 这个是不是少了个where