至少一个参数没有被指定值
public class DataAccess
{
static OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.Oledb.4.0;Data Source=" + System.Web.HttpContext.Current.Server.MapPath(@"~/App_Data/B2C.mdb"));
public static DataSet getOleServerData(string sqlstring)
{
OleDbDataAdapter adapter = null;
DataSet ds = new DataSet();
try
{
conn.Open();
adapter = new OleDbDataAdapter();
adapter.SelectCommand = new OleDbCommand(sqlstring, conn);
adapter.Fill(ds);
}
finally
{
conn.Close();
}
return ds;
}
}
protected void btLogon1_Click(object sender, EventArgs e)
{
DataSet ds = DataAccess.getOleServerData(@"SELECT C-Password, C-Name FROM CUSTOMER WHERE C-Email LIKE '" + TextBox2.Text + "'");
GridView1.DataSource = ds.Tables[0];
GridView1.DataBind();
}
运行后出错:至少一个参数没有被指定值。是怎么回事?