How to find label control from content page which

I have one page:Abc.aspx

On this Abc.aspx page i have used one master page that is Master1.Master.

Now on this master page i have rendered 1 usercontrol name as Usercontrol1.ascx.

On this User control i have put 1 label named as lbl1.

 <asp:Label runat="server" ID="lbl1"></asp:Label>

So now on page load event of Abc.aspx page i want to find this control and i have tried but getting null:

 protected void Page_Load(object sender, EventArgs e)
        {
            var lbl = ((Label)this.Master.FindControl("lbl1")); // null here
            ((Label)this.Page.Master.FindControl("lbl1")).Text = "Hello"; //error here:object reference not set to instance of object
        }

This is my master page:

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Master1.Master.cs" Inherits="" %>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<asp:ContentPlaceHolder ID="head" runat="server"></asp:ContentPlaceHolder>
</head>

<body>
    <form runat="server">
   <div id="Load">
                    <uc2:UserControl1 ID="UserControl1 " runat="server" />
                    <asp:ContentPlaceHolder ID="cphMain" runat="server">
                    </asp:ContentPlaceHolder>
                </div>
 </form>
</body>
</html>

标签： c# asp.net user-controls master-pages findcontrol

3条回答

Luminary・发光体

2楼-- · 2019-07-07 12:27

Have you tried to first find the parent container of the user control (e.g. #ParentContainer) and then use FindControl on this object to find the desired user control?

See: Find a control on a page with a master page

Like this:

UserControl control = this.Master.FindControl("ParentContainer").FindControl("lbl1") as UserControl;

0人赞添加讨论(0) 举报

The star\"

3楼-- · 2019-07-07 12:34

The best approach is to provide a property in your MasterPage with a meaningful name and type string. This property gets/sets the text of the label in the UserControl.

In order to meet this objective provide also a property in your UserControl with the same meaningful name and type string. This property gets/sets the text of the label.

You have to cast this.Master to the actual type of your MasterPage which is Master1. Then you can access this custom property.

So here is your UserControl:

public partial class UserControl1 : System.Web.UI.UserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    public string MeaningfulNameForLabelText
    {
        get { return this.lbl1.Text; }
        set { this.lbl1.Text = value; }
    } 
}

This is your MasterPage

public partial class Master1 : System.Web.UI.MasterPage
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    public string MeaningfulNameForLabelText
    {
        get { return this.UserControl1.MeaningfulNameForLabelText; }
        set { this.UserControl1.MeaningfulNameForLabelText = value; }
    } 
}

and this is your page:

protected void Page_Load(object sender, EventArgs e)
{
    var master = this.Master as Master1;
    if (master != null)
    {
        master.MeaningfulNameForLabelText = "Hello";
    }
}

0人赞添加讨论(0) 举报

再贱就再见

4楼-- · 2019-07-07 12:39

Ok after some research i have found he answer:

First i have find that user control like below:

UserControl uch = Page.Master.FindControl("UserControl1 ") as UserControl;

After this i am finding my label from this user control like this:

if(uch!=null)
            {
                var data = (Label)uch.FindControl("lbl1");
                var d = data.Text; //getting text successfully
            }

0人赞添加讨论(0) 举报

How to find label control from content page which

采纳回答

编辑标签

举报内容

检举类型

检举原因

检举说明(必填)

打开微信“扫一扫”，打开网页后点击屏幕右上角分享按钮

付费偷看金额在0.1-10元之间