使用下拉列表從數據庫中刪除

Question

嗨即時通訊使用下拉列表從表中獲取id，然後刪除行刪除buton當我運行頁面時dropdownlist獲取表中所有的id都好，但當我刪除它始終刪除最後一個ID，即使我選擇另一

List<classe_cv_langues> li6 = new List<classe_cv_langues>(); 
    SqlConnection con4 = new SqlConnection(@"Data Source=p5-pc\sqlexpress;Initial Catalog=recrutement_online_3;Integrated Security=True"); 
    SqlCommand cmd4 = new SqlCommand(); 
    cmd4.Connection = con4; 
    con4.Open(); 
    cmd4.CommandText = "select id from cv_langues as cl inner join cv as c on cl.id_cv = c.id_cv where id_candidat= " + Session["Id_candidat"]; 
    SqlDataReader dr4 = cmd4.ExecuteReader(); 
    while (dr4.Read()) 
    { 
     classe_cv_langues p6 = new classe_cv_langues(); 
     p6.Id = int.Parse(dr4[0].ToString()); 
     li6.Add(p6); 


    } 
    dr4.Close(); 
    con4.Close(); 


    DropDownList7.DataSource = li6; 
    DropDownList7.DataTextField = "id"; 
    DropDownList7.DataValueField ="id"; 

    DropDownList7.DataBind() 

刪除布敦：

SqlConnection con = new SqlConnection(@"Data Source=p5-pc\sqlexpress;Initial Catalog=recrutement_online_3;Integrated Security=True"); 
    SqlCommand cmd = new SqlCommand(); 
    cmd.Connection = con; 
    con.Open(); 
    cmd.CommandText = "delete from cv_langues where id='"+DropDownList7.SelectedValue+"'"; 
    cmd.ExecuteNonQuery(); 
    con.Close(); 

    Server.Transfer("gestion_cv.aspx"); 

Answer 1

假設你的綁定邏輯是Page_Load方法。嘗試測試的Page.IsPostBack

if (!Page.IsPostBack) 
{ 
    List<classe_cv_langues> li6 = new List<classe_cv_langues>(); 
    SqlConnection con4 = new SqlConnection(@"Data Source=p5-pc\sqlexpress;Initial Catalog=recrutement_online_3;Integrated Security=True"); 
    SqlCommand cmd4 = new SqlCommand(); 
    cmd4.Connection = con4; 
    con4.Open(); 
    cmd4.CommandText = "select id from cv_langues as cl inner join cv as c on cl.id_cv = c.id_cv where id_candidat= " + Session["Id_candidat"]; 
    SqlDataReader dr4 = cmd4.ExecuteReader(); 
    while (dr4.Read()) 
    { 
     classe_cv_langues p6 = new classe_cv_langues(); 
     p6.Id = int.Parse(dr4[0].ToString()); 
     li6.Add(p6); 


    } 
    dr4.Close(); 
    con4.Close(); 


    DropDownList7.DataSource = li6; 
    DropDownList7.DataTextField = "id"; 
    DropDownList7.DataValueField ="id"; 

    DropDownList7.DataBind() 
}