以编程方式将用户控件添加到页面，同时保留已存在的控件

发布于 2024-10-25 22:13:05 字数 535 浏览 2 评论 0原文

我正在尝试在运行时将用户控件添加到 div 中。我可以毫无问题地添加控件，但它会覆盖以前添加的控件。

基本上，我正在尝试将乘客添加到旅行系统中 - 乘客详细信息位于用户控件中，我事先不知道会有多少人。我有一个添加新乘客按钮，该按钮应将新用户控件附加到 div 中，而不会覆盖以前的乘客。

代码是 c#/.net 4。

我尝试将控制数据保存到视图状态中，然后将其重新添加到新的视图状态中，但这也不起作用。这是我正在使用的代码片段

foreach (Control uc in p_passengers.Controls) {
        Passenger p = uc as Passenger;
        if (p != null) {
            p.SaveValues();            
        }
    }

，但是，p.SaveAs()（仅将控制值写入 ViewState）永远不会被命中。

我确定这只是一些愚蠢的事情，但有什么想法吗？

干杯，伙计们。

原文

I am trying to add a user control into a div at runtime. I can add the control no probelem but it overwrites the previous control added.

Basically, I am trying to add passengers to a travel system - the passenger details are in the user control and I don't know in advance how many there will be. I have an add new passenger button which should append the new user control into the div without overwriting the previous passenger.

The code is c#/.net 4.

I have tried to save the control data into viewstate and re add it with the new one but that also doesn't work. Here is a snippet of the code I'm using

foreach (Control uc in p_passengers.Controls) {
        Passenger p = uc as Passenger;
        if (p != null) {
            p.SaveValues();            
        }
    }

however, p.SaveAs() (just writes the control values into ViewState) is never hit.

Im sure its just something stupid but any ideas??

Cheers guys.

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樱花细雨 2024-11-01 22:13:06

您是否为每次回发重新创建所有动态控件？

请记住，每个回发都是 Page 类的一个新实例，并且您之前创建的任何控件都需要显式地重新创建。

更新

如果您在视图状态中有一个添加项目的列表，类似这样..

    private List<string> Items
    {
         get
         {
              return ViewState["Items"] = (ViewState["Items"] ?? new List<string>());
         }
    }

然后在您的点击处理程序中，您可以简单地添加到此列表：

   private void btn_Click(object sender, EventArgs e)
   {
        this.Items.Add("Another Item");
   }

然后覆盖 CreateChildControls

  protected overrides CreateChildControls()
  {
       foreach (string item in this.Items)
       {
            Passanger p = new Passenger();
            p.Something = item;
            this.p_passengers.Controls.Add(p);
       }
  }

Are you re-creating all of your dynamic controls for every postback?

Remember each postback is a new instance of the Page class and any controls you previously created will need to be explicitly re-created.

Update

If you had a list of added items in viewstate, something like this..

    private List<string> Items
    {
         get
         {
              return ViewState["Items"] = (ViewState["Items"] ?? new List<string>());
         }
    }

Then in your click handler you could simply add to this list :

   private void btn_Click(object sender, EventArgs e)
   {
        this.Items.Add("Another Item");
   }

Then override CreateChildControls

  protected overrides CreateChildControls()
  {
       foreach (string item in this.Items)
       {
            Passanger p = new Passenger();
            p.Something = item;
            this.p_passengers.Controls.Add(p);
       }
  }

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