Gridview控件綁定DropDownlist

Question

請幫我這個。我在我的頁面上有一個包含2個下拉列表（大學和學院）的GridView控件。大學約在page_load事件，而大學取決於Uninversity.selectedValue。我有一個添加按鈕，將新行添加到網格中。

問題是有超過1行時。我無法確定哪個大學在onselectedIndexChanged賽事上具有約束力。它不斷綁定第一排學院。

這是我在我的SelectedIndexChanged方法

protected void drpUniversityName_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     GridViewRowEventArgs e1 = (GridViewRowEventArgs)e; // Gives me a casting error on this line 
     DropDownList drpUniversityName = (DropDownList)(e1.Row.FindControl("drpUniversityName")); 
     DropDownList drpCollegeName = (DropDownList)(e1.Row.FindControl("drpCollegeName")); 
     bindColleges(drpUniversityName,drpCollegeName); 
    } 

迄今所做的，我需要一些方法來獲取當前行的大學和學院。

Answer 1

<asp:GridView ID="GridView1" runat="server" > 
      <Columns> 
       <asp:TemplateField> 
        <ItemTemplate> 
         <asp:DropDownList ID="ddlUniversity" runat="server" AutoPostBack="True" 
          onselectedindexchanged="ddlUniversity_SelectedIndexChanged"> 
          <asp:ListItem>1</asp:ListItem> 
          <asp:ListItem>2</asp:ListItem> 
          <asp:ListItem>3</asp:ListItem> 
         </asp:DropDownList> 
        </ItemTemplate> 
       </asp:TemplateField> 
       <asp:TemplateField> 
        <ItemTemplate> 
         <asp:DropDownList ID="ddlCollege" runat="server"> 
         </asp:DropDownList> 
        </ItemTemplate> 
       </asp:TemplateField> 
      </Columns> 
     </asp:GridView> 

，這裏是C＃代碼：

protected void Page_Load(object sender, EventArgs e) 
    { 
     if (!IsPostBack) 
      GridView_DataBind(); 
    } 

    private void GridView_DataBind() 
    { 
     string[] datasource = { "1", "2", "3" }; 

     GridView1.DataSource = datasource; 
     GridView1.DataBind(); 
    } 

    protected void ddlUniversity_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     GridViewRow currentRow = (GridViewRow)((Control)sender).NamingContainer; 

     //your code here 
    }