Makinkg動態的DropDownList

Question

我嘗試進行動態DropDownList這樣：

<form id="form1" runat="server"> 
<asp:DropDownList ID="ddlCategory" runat="server" AutoPostBack="True" 
    onselectedindexchanged="CategoryDropList_SelectedIndexChanged" /> 
</form> 

void DropListInit() 
{ 
    Dictionary<string, string> dic = new Dictionary<string, string>(); 
    dic.Add("1","apple"); 
    dic.Add("2","banana"); 
    ddlCategory.DataSource = dic; 
    ddlCategory.DataTextField = "value"; 
    ddlCategory.DataValueField = "key"; 
    ddlCategory.DataBind(); 
} 

protected void Page_LoadComplete(object sender, EventArgs e) 
{ 
    DropListInit(); 
} 

protected void CategoryDropList_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    ddlCategory.SelectedValue = ddlCategory.SelectedValue; 
} 

而且我發現，在沒有沒有這種奇怪的表情ddlCategory.SelectedValue = ddlCategory.SelectedValue;所以工作時，這是什麼表現手法？或者我做錯了什麼？

Answer 1

將DropListInit移動到Page_load，如下所示;

protected void Page_LoadComplete(object sender, EventArgs e) 
{ 
    if (!IsPostBack)  
    { 
     DropListInit(); 
    } 
} 

刪除此;

ddlCategory.SelectedValue = ddlCategory.SelectedValue; 

應該沒問題。