Question

C#至少一个参数没有被指定值

出错在oda.Fill(ds);

protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
string sqlp = "select * from province";
this.ddlProv.DataSource = DB.GetDS(sqlp);
this.ddlProv.DataTextField = "province";
this.ddlProv.DataValueField = "provinceID";
this.ddlProv.DataBind();
string sqlc = "select * from city where father=" + this.ddlProv.DataValueField;
this.ddlCity.DataSource = DB.GetDS(sqlc);
this.ddlCity.DataTextField = "city";
this.ddlCity.DataValueField = "cityID";
this.ddlCity.DataBind();
string sqla = "select * from area where father=" + this.ddlCity.DataValueField;
this.ddlArea.DataSource = DB.GetDS(sqla);
this.ddlArea.DataTextField = "area";
this.ddlArea.DataValueField = "areaID";
this.ddlArea.DataBind();
}
}
public static DataSet GetDS(string sql)
{
OleDbConnection con = DB.CreateCon();
con.Open();
OleDbDataAdapter oda = new OleDbDataAdapter(sql, con);
DataSet ds = new DataSet();
oda.Fill(ds);
return ds;
}
ddlCity的值(市)是由ddlProv的值(省)所对应的ID确定下来,所以应该是SQL语句错了,不过要怎么改写呢?

Answer 1

sql查询语句，字符型参数需要加单引号限定！
WHERE P.[Ltype]='" + text + "' AND P.[DepID] ='" + u +"' ORDER BY InputTime DESC"
结尾的双引号不要丢！

Answer 2

是你某个方法的实参不对，少了实参或者是类型有问题
出错在oda.Fill(ds);如果ds是个dataset类，你就少加个名称
可以改成oda.Fill(ds, "表名");

Answer 3

是SQL语句有列名或表名写错了，检查下。

Answer 4

有空值，搂主在赋值前作一下检验就行了