[英]FindControl of a Formview which is inside an user control
我的aspx页面内有一个Multiformview,例如:
<data:MultiFormView ID="mFormView1" DataKeyNames="Id" runat="server" DataSourceID="DataSource">
<EditItemTemplate>
<ucl:myControl ID="myControl1" runat="server" />
</EditItemTemplate>
在用户控件“ mycontrol”中,我有一个下拉列表,如下所示:
<asp:FormView ID="FormView1" runat="server" OnItemCreated="FormView1_ItemCreated">
<ItemTemplate>
<table border="0" cellpadding="3" cellspacing="1">
<tr>
<td>
<asp:DropDownList ID="ddlType" runat="server" Width="154px" />
</td>
</tr>
因此,当我尝试访问ascx.cs文件中的该dropdownlist时,它给了我null引用错误。
我尝试了以下操作:
protected void FormView1_ItemCreated(Object sender, EventArgs e)
{
DropDownList ddlType= FormView1.FindControl("ddlType") as DropDownList;
}
和
DropDownList ddlType= (DropDownList)FormView1.FindControl("ddlType");
AND:也在Databound内部。 什么都没用。
编辑:
我没有检查Formview1.Row是否为null。 解决方法如下:
protected void FormView1_DataBound(object sender, EventArgs e)
{
DropDownList ddlType = null;
if (FormView1.Row != null)
{
ddlType = (DropDownList)FormView1.Row.FindControl("ddlType");
}
}
这是一个扩展方法,它允许搜索递归。 它使用FindControlRecursive方法扩展了当前的控制。
using System;
using System.Web;
using System.Web.UI;
public static class PageExtensionMethods
{
public static Control FindControlRecursive(this Control ctrl, string controlID)
{
if (ctrl == null || ctrl.Controls == null)
return null;
if (String.Equals(ctrl.ID, controlID, StringComparison.OrdinalIgnoreCase))
{
// We found the control!
return ctrl;
}
// Recurse through ctrl's Controls collections
foreach (Control child in ctrl.Controls)
{
Control lookFor = FindControlRecursive(child, controlID);
if (lookFor != null)
return lookFor;
// We found the control
}
// If we reach here, control was not found
return null;
}
}
我没有检查Formview1.Row是否为null。 解决方法如下:
protected void FormView1_DataBound(object sender, EventArgs e)
{
DropDownList ddlType = null;
if (FormView1.Row != null)
{
ddlType = (DropDownList)FormView1.Row.FindControl("ddlType");
}
}
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