更新并在gridview中显示（ASP c＃）

Question

can someone tell me where is the error in this code :

 protected void btnValiderModifier_Click(object sender, EventArgs e)
        {
            try
            {
                string myid;
                for (int i = 0; i < gv_enfant.Rows.Count; i++)
                {
                    CheckBox chbox = (CheckBox)gv_enfant.Rows[i].Cells[0].FindControl("CheckBoxenfant");
                    if (chbox.Checked)
                    {
                        myid = ((HiddenField)gv_enfant.Rows[i].Cells[0].FindControl("codeenfant")).Value;

                }
            }

            c.cmd = c.cn.CreateCommand();
            c.cmd.CommandText = "update Enfants set prenom ='" + TextBox_NPmodif.Text + "',DateNaissance='" + TextBox_DNmodif.Text + "', Scolarise='" + TextBox_Scolarisemodif.Text + "',Activite= '" + TextBox_Activitemodif.Text +"' where codeEnfants =" + myid;
            if (c.cn.State == ConnectionState.Closed)
            {
                c.cn.Open();
            }
            c.cmd.ExecuteNonQuery();
            Response.Write("<script>alert('Opération reussie')</script>");
            gv_enfant.DataBind();

        }
        catch(Exception ex)
        {
            Response.Write("<script>alert ('Erreur lors de la modif!')</script>");
        }
        finally
        {
            if (c.cn.State == ConnectionState.Open)
            {
                c.cn.Close();
            }
        }
    }

this code make an update in table "Enfants" then it display iu gridview , when i debug i have this error = " Incorrect syntax near '=' " thank you

Answer 1

My reputation isn't high enough to add a comment, but I have to ask: is "myid" definitely an integer/double? If not, you'll have to enclose it in single quotes as well.

Answer 2

You decalre myid as a string then you forgot to quote it where codeEnfants =" + myid;

You should not add the parameters this way anyway, try like this:

protected void btnValiderModifier_Click(object sender, EventArgs e)
{
    using(SqlConnection conn = new SqlConnection(connString))
    {
            string myid;
            for (int i = 0; i < gv_enfant.Rows.Count; i++)
            {
                CheckBox chbox = (CheckBox)gv_enfant.Rows[i].Cells[0].FindControl("CheckBoxenfant");
                if (chbox.Checked)
                {
                    myid = ((HiddenField)gv_enfant.Rows[i].Cells[0].FindControl("codeenfant")).Value;

                }
            }
        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand("update Enfants set prenom =@prenom,  DateNaissance=@dateNaissance, Scolarise=@scolarise, Activite=@activite where codeEnfants=@codeEnfants", conn);
            cmd.Parameters.AddWithValue("@prenom", TextBox_NPmodif.Text);
            cmd.Parameters.AddWithValue("@DateNaissance", TextBox_DNmodif.Text);
            cmd.Parameters.AddWithValue("@Scolarise", TextBox_Scolarisemodif.Text);
            cmd.Parameters.AddWithValue("@Activite", TextBox_Activitemodif.Text);
            cmd.Parameters.AddWithValue("@codeEnfants", myid);
            cmd.ExecuteNonQuery();

            //success!
            Response.Write("<script>alert('Opération reussie')</script>");
            gv_enfant.DataBind();
        }
        catch(SqlException sqlEx)
        {
            //fail!
            //what is the point of cacthing if you do use the exception?
            Response.Write("error" + sqlEx.Message);
            Response.Write("<script>alert ('Erreur lors de la modif!')</script>");
        }
    }
}