Question

C#datagridview绑定access，传参失败

string strPath = @"Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=False;Data Source=|DataDirectory|\教务管理.accdb";
OleDbConnection con = new OleDbConnection(strPath);
con.Open();
string sql = "select 课程名,课程号,学分,课程属性,考试类型,替代课程号,成绩 from 成绩 where 学号=@username";
OleDbCommand cmd = new OleDbCommand(sql,con); //cmd.CommandText = sql;//cmd = con.CreateCommand();
cmd.Parameters.AddWithValue("@username", uname);
OleDbDataAdapter ad = new OleDbDataAdapter(sql, con);
DataTable dt = new DataTable();
ad.Fill(dt);
dataGridView1.DataSource = dt.DefaultView;
con.Close();
其他都对的，把Where去掉就可以，应该是@username没赋值成功，求解，不知道怎么弄

Answer 1

string sql =string.Format("select 课程名,课程号,学分,课程属性,考试类型,替代课程号,成绩 from 成绩 where 学号='{0}'",uname); 
//cmd.Parameters.AddWithValue("@username", uname); 注释掉这行