更新的GridView有DropDownList控件

Question

我在下面的一行代碼：

cmd.Parameters.Add("@priority", SqlDbType.VarChar).Value = ((DropDownList)GridView1.Rows[e.RowIndex].Cells[4].Controls[0]).SelectedValue; 

但是當我運行它，我得到以下錯誤：

Unable to cast object of type 'System.Web.UI.LiteralControl' to type 'System.Web.UI.WebControls.DropDownList'. 

任何想法，這可能是爲什麼？

---

在GridView的

相關部分將是這樣的：

<asp:TemplateField HeaderText="Priority"> 
    <ItemTemplate> 
     <asp:Label ID="Label1" runat="server" Text='<%# Bind("priority") %>'></asp:Label> 
    </ItemTemplate> 
    <EditItemTemplate> 
     <asp:DropDownList ID="DropDownList1" runat="server" 
      SelectedValue='<%# Bind("priority") %>'> 
      <asp:ListItem Value="0">Low</asp:ListItem> 
      <asp:ListItem Value="1">Normal</asp:ListItem> 
      <asp:ListItem Value="2">High</asp:ListItem> 
     </asp:DropDownList> 
    </EditItemTemplate> 
</asp:TemplateField> 

Answer 1

由於您DropDownList最有可能是在TemplateField你可以得到它的參考通過FindControl("ID")：

public void gv_RowUpdating(object sender, GridViewUpdateEventArgs e) 
{ 
    GridView gv = (GridView)sender; 
    GridViewRow row = gv.Rows[e.RowIndex]; 
    // assuming its ID is "DropDownList1" 
    DropDownList ddl = (DropDownList)row.FindControl("DropDownList1"); 
    String selectedValue = ddl.SelectedValue; 

Answer 2

您必須的RowDataBound

使用 e.Item.FindControl

var ddl = (DropDownList) e.Item.FindControl("YourId"); 
var value = ddl.SelectedValue; 

Answer 3

這將這樣的伎倆

public void gv_RowUpdating(object sender, GridViewUpdateEventArgs e) 
{ 
    string spacediv3 = ((DropDownList)gridviewname.Rows[e.RowIndex].Cells[location].FindControl("dropdownlit1")).SelectedItem.ToString(); 
}