[英]Can I call page_load event of usercontrol before page_load event of aspx page?
The question is straight forward.Can I call page_load of usercontrol before page_load of aspx page? 问题很简单,我可以在aspx页面的page_load之前调用usercontrol的page_load吗?
EDIT 编辑
Its not possible to call the child's page_load event before parent's page_load. 无法在父级的page_load之前调用子级的page_load事件。
I have this aspx class called just4test for testing puropse. 我有一个名为just4test的aspx类,用于测试钱包。 Its aspx code is:
其aspx代码为:
<body>
<form id="form1" runat="server">
<uc1:lcont ID="lcont1" runat="server" />
<div>
</div>
</form>
As you can see it is using a usercontrol file. 如您所见,它正在使用一个usercontrol文件。
And its code behind is : 其背后的代码是:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
lcont1.my_tv_SelectedNodeChanged(sender, e);
}
}
Now the usercontrol is: 现在,用户控件为:
public partial class lcont : System.Web.UI.UserControl
{
sql_con sq = new sql_con();
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
bind_data();
}
}
public void mytry()
{
Console.WriteLine("helo");
}
public void bind_data()
{
main_cat mcobj = new main_cat();
List<main_cat> mclist = new List<main_cat>();
mclist = mcobj.get_mcatlist();
populatetree(mclist);
}
public void populatetree(List<main_cat> mytnode)
{
TreeNode parentnode = null;
foreach (main_cat mc in mytnode)
{
parentnode = new TreeNode(mc.Cname, mc.Cid.ToString());
foreach (sub_cat sc in mc.scl)
{
TreeNode cnode = new TreeNode(sc.PRODUCT, sc.SID.ToString());
parentnode.ChildNodes.Add(cnode);
}
parentnode.Collapse();
my_tv.Nodes.Add(parentnode);
}
}
public void my_tv_SelectedNodeChanged(object sender, EventArgs e)
{
TreeView tv = sender as TreeView;
//TreeView tv = new TreeView();
var selectedN = tv.SelectedNode;
if (selectedN.Parent != null)
{
var id = tv.SelectedNode.Value;
var name = tv.SelectedNode.Text;
//Session["mySvar"] = id;
ScriptManager.RegisterStartupScript(this, this.GetType(), "nething", "show("+id+")", true);
}
else
{
//Response.Redirect("test.aspx");
}
}
} }
I need to call the function my_tv_SelectedNodeChanged(sender, e); 我需要调用函数my_tv_SelectedNodeChanged(sender,e); of usercontrol before the page_load of just4test page and i have done so.But when i run the program it says
在just4test页面的page_load之前的usercontrol控件,我这样做了。但是当我运行程序时,它说
Object reference not set to an instance of an object.
你调用的对象是空的。
What should i do? 我该怎么办?
Page_Load no, but OnInit occures before. Page_Load否,但之前发生过OnInit。 Depends on your actual problem, you can move your logic there.
根据您的实际问题,可以将逻辑移到那里。
Or call a public method of the User control before you do anything else in the Parent Page Page_Load event 或在执行父页面Page_Load事件中的任何其他操作之前,先调用User控件的公共方法。
See Page Life Cycle 参见页面生命周期
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