如何在页面上找到我的用户控件。 [英] how to find my user control on a page.
问题描述
我制作了一个显示消息框的公共用户控件（messagecontrol.ascx）。我已将此usercontrol放在我的母版页中。
在我的母版页中还有一个名为header.ascx的usercontrol，当用户单击header.ascx控件的按钮时，它也会调用此usercontrol。它的工作正常。
但是当制作一个带有相同主页的新cart.aspx页面时。并放置一个按钮和调用按钮单击我在header.ascx按钮中写入的同一事件，它给出了null referece错误。
Messagecontrol.ascx中的代码
public void Page_Load（object sender，EventArgs e）
{
lblMessage。 Text = Message;
lblMessage1.Text = Message1;
if（Message！= string.Empty&& Message！= null）
SendErrorModelPopupExtender.Show（）;
}
public string Message {get;组; }
公共字符串Message1 {get;组; }
Header.ascx中的代码（此处正常工作）
protected void btnCheckOut_Click（object sender，EventArgs e）
{
if（ShoppingCart.Instance.Items。计数== 0）
{
CustomMessageControls uc1 =（CustomMessageControls）this.Parent.Parent.FindControl（MessageControl1）;
uc1 .Message =购物车中没有找到商品。请在购物车中添加商品以结帐;
uc1.Message1 =找不到商品;
uc1.Page_Load（uc1 ，EventArgs.Empty）;
}
else
Response.Redirect（checkout.aspx）;
}
我在cart.aspx页面中调用相同的代码，但是它给出了错误
cart.aspx中的代码
protected void btnCheckOut_Click（object sender，EventArgs e ）
{
if（ShoppingCart.Instance.Items.Count == 0）
{
CustomMessageControls uc1 =（CustomMessageControls）this.FindControl（MessageControl1）;
uc1.Message =购物车中找不到商品。请在购物车中添加商品以结帐;
uc1.Message1 =找不到商品;
uc1.Page_Load（uc1，EventArgs.Empty）;
}
其他
Response.Redirect（checkout.aspx）;
}
当我点击cart.aspx页面按钮时出现错误
我还添加了<％@ Reference VirtualPath =〜/ Controls / CustomMessageControls.ascx％>
异常详情：System.NullReferenceException ：对象引用未设置为对象的实例。
源错误：
第39行：{
第40行：CustomMessageControls uc1 =（CustomMessageControls）this.FindControl（MessageControl1）;
第41行：uc1.Message = 购物车中没有找到物品。请在购物车中添加商品以结帐;
第42行：uc1.Message1 =找不到商品;
第43行：uc1.Page_Load（uc1，EventArgs.Empty ）;
请帮帮我
谢谢
Ram Kumar
我不确定你是如何放置控件的，但你可能需要通过使用Parent属性找到控件，如下所示
CustomMessageControls uc1 =（CustomMessageControls） this .Parent.FindControl（ MessageControl1）;
或
CustomMessageControls uc1 =（CustomMessageControls） this .Parent.Parent.FindControl（ MessageControl1\" ）;
I have make a common usercontrol (messagecontrol.ascx) which display message box. and I have place this usercontrol in my masterpage.
In my master page also a usercontrol named header.ascx which also call this usercontrol when user click on button of a header.ascx control. its working properly.
But when make a new cart.aspx page with same masterpage. and place a button and call button click same event which i write in header.ascx button its give null referece error.
code in Messagecontrol.ascx
public void Page_Load(object sender, EventArgs e)
{
lblMessage.Text = Message;
lblMessage1.Text = Message1;
if (Message != string.Empty && Message !=null)
SendErrorModelPopupExtender.Show();
}
public string Message { get; set; }
public string Message1 { get; set; }
code in Header.ascx (Here working Properly)
protected void btnCheckOut_Click(object sender, EventArgs e)
{
if (ShoppingCart.Instance.Items.Count == 0)
{
CustomMessageControls uc1 = (CustomMessageControls)this.Parent.Parent.FindControl("MessageControl1");
uc1.Message = "No Item Found in cart. Please add item in cart to checkout";
uc1.Message1 = "No Item Found";
uc1.Page_Load(uc1, EventArgs.Empty);
}
else
Response.Redirect("checkout.aspx");
}
Same code i call in cart.aspx page but its give error
code in cart.aspx
protected void btnCheckOut_Click(object sender, EventArgs e)
{
if (ShoppingCart.Instance.Items.Count == 0)
{
CustomMessageControls uc1 = (CustomMessageControls)this.FindControl("MessageControl1");
uc1.Message = "No Item Found in cart. Please add item in cart to checkout";
uc1.Message1 = "No Item Found";
uc1.Page_Load(uc1, EventArgs.Empty);
}
else
Response.Redirect("checkout.aspx");
}
When I click on cart.aspx page button it's error
I have also add the <%@ Reference VirtualPath="~/Controls/CustomMessageControls.ascx" %>
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 39: {
Line 40: CustomMessageControls uc1 = (CustomMessageControls)this.FindControl("MessageControl1");
Line 41: uc1.Message = "No Item Found in cart. Please add item in cart to checkout";
Line 42: uc1.Message1 = "No Item Found";
Line 43: uc1.Page_Load(uc1, EventArgs.Empty);
Please help me
Thanks
Ram Kumar
I'm not sure how you placed your controls, but you may need to find controls by using Parent property as below
CustomMessageControls uc1 = (CustomMessageControls)this.Parent.FindControl("MessageControl1");
or
CustomMessageControls uc1 = (CustomMessageControls)this.Parent.Parent.FindControl("MessageControl1");
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