简单问题，解决给分

[siyuan6689]

我在进行用户信息修改的时候出现错误提示“已有打开的与此命令相关联的 DataReader，必须首先将它关闭。”请问如何解决
protected void Submit_Click(object sender, EventArgs e)
{

string strconn = ConfigurationSettings.AppSettings["ConnectionString"];
SqlConnection conn = new SqlConnection(strconn);
conn.Open();
string strsql = "update client set client_name='" + client_name.Text + "',client_pwd='" + client_pwd.Text + "',client_email='" + client_email.Text + "',client_tell='" + client_tell.Text + "',client_company='" + client_company.Text + "',client_vocation='" + client_vocation.Text + "' where client_id='" + Session["client_id"].ToString() + "' ";
SqlCommand cm = new SqlCommand(strsql, conn);
SqlDataReader dr = cm.ExecuteReader();

if (dr.Read())
{
//保存用户权限
Session["client_id"] = dr["client_id"];
}
try
{
cm.ExecuteNonQuery();
Response.Redirect("client_index.aspx?client_id='" + Session["client_id"] + "'");
}
catch (Exception ex)
{

Lbl_note.Text = ex.Message;
Lbl_note.Style["color"] = "red";
}
finally
{
cm.Dispose();
conn.Close();
dr.Close();
}
}

[zzyhuian06142]

你的是update 语句,又不是Select语句,DataReader能得到值吗?

[zzyhuian06142]

针对你的问题
你在if(dr.Read())上面加个
if(!dr.IsClosed)
{
dr.Close();
}

[金欧]

try
{
cm.ExecuteNonQuery();
//释放资源.......

Response.Redirect("client_index.aspx?client_id='" + Session["client_id"] + "'");
}
这里先释放资源，再redirect应该就可以了

[kkun_3yue3]

string strconn = ConfigurationSettings.AppSettings["ConnectionString"];
            SqlConnection conn = new SqlConnection(strconn);
            conn.Open();
            string strsql = "update client set client_name='" + client_name.Text + "',client_pwd='" + client_pwd.Text + "',client_email='" + client_email.Text + "',client_tell='" + client_tell.Text + "',client_company='" + client_company.Text + "',client_vocation='" + client_vocation.Text + "' where client_id='" + Session["client_id"].ToString() + "' ";
            SqlCommand cm = new SqlCommand(strsql, conn);
            SqlDataReader dr = cm.ExecuteReader();

            if (dr.Read())
            {
                //保存用户权限
                Session["client_id"] = dr["client_id"];
            }
            try
            {
                dr.Close();
                cm.ExecuteNonQuery();
                Response.Redirect("client_index.aspx?client_id='" + Session["client_id"] + "'");
            }
            catch (Exception ex)
            {

                Lbl_note.Text = ex.Message;
                Lbl_note.Style["color"] = "red";
            }
            finally
            {
                cm.Dispose();
                conn.Close();
                dr.Close();
            }

DR用完就关闭,再用再打开,

[GT7466]

主要原因是 DataReader 在打开使用时，一个 SqlConnection 只允许打开一个 DataReader，在开启另一个 DataReader 时，必须将前面一个先 Close 掉。

在ExecuteNonQuery() 后，内部会生成一个空的 DataReader 对象，并当当前的数据库连接关闭掉后，该 DataReader 才会释放