在RowCommand上填充DDL

Question

我有一个带有rowcommand和linkbutton的网格视图。但是，当我按下“链接”按钮时，行将被编辑，但是DDL应该将数据绑定到我的数据库中的值，但这是行不通的。

我不知道这是否是正确的方法，但当按链接按钮“对象引用未设置为对象的实例”时，确实会出现错误。但我不认为这是主要问题。

在编辑Rowcommand时，我应该绑定我的DDL行，还是有人可以看到我做错了什么？

DDL列的ASPX标记：

<asp:TemplateField HeaderText="Status">
                 <EditItemTemplate>
                     <asp:DropDownList ID="ddlStatusRow" AppendDataBoundItems="True" runat="server" > 
                       <asp:ListItem>Status</asp:ListItem>  

                     </asp:DropDownList>
                     <asp:RequiredFieldValidator ID="rfEditStatus" runat="server" ErrorMessage ="Status is a required field"
                         ControlToValidate="ddlStatusRow" Text="*" ForColor="Red" InitialValue="Status">
                     </asp:RequiredFieldValidator>
                 </EditItemTemplate>
                 <ItemTemplate>
                     <asp:Label ID="Label1" runat="server" Text='<%# Bind("Status") %>'></asp:Label>
                 </ItemTemplate>
                 <HeaderStyle BackColor="#E6E6E6" Font-Bold="False" Font-Names="Arial" Font-Size="14px" ForeColor="Black" />
                 <ItemStyle Font-Size="12px" HorizontalAlign="Center" Width="4%" />
             </asp:TemplateField>

CodeBehind：

protected void gwUnplannedActivities_RowCommand(object sender, GridViewCommandEventArgs e)
{

    if (e.CommandName == "EditRow")
    {
        int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;
        gwUnplannedActivities.EditIndex = rowIndex;
        BindGridViewUnplannedActivities();

        GridViewRow row = ((e.CommandSource as Control).NamingContainer as GridViewRow);
        DropDownList ddlStatusRow = (DropDownList)row.Cells[3].FindControl("ddlStatusRow");  


        string CS = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;


        using (SqlConnection con = new SqlConnection(CS))
        {
            SqlCommand cmd = new SqlCommand("SELECT * FROM ....", con);
            con.Open();
            ddlStatusRow.DataSource = cmd.ExecuteReader();
            ddlStatusRow.DataTextField = "Status";
            ddlStatusRow.DataBind();
        }

    }
    else if (e.CommandName == "CancelUpdate")
    {
       //somecode....
    }
    else if (e.CommandName == "UpdateRow")
    {
        //somecode....
    }


}

Answer 1

使用这个

GridView gv = (GridView)sender;
DropDownList ddlStatusRow = (DropDownList)gv.Rows[rowIndex].FindControl("ddlStatusRow");

而不是

GridViewRow row = ((e.CommandSource as Control).NamingContainer as GridViewRow);
DropDownList ddlStatusRow = (DropDownList)row.Cells[3].FindControl("ddlStatusRow");

问题是编辑索引已经设置好了，所以row不再存在了，因为它已经被可编辑行取代了。