Asp.net 从添加到回发占位符的复合控件中获取数据

我试图创建一个基于CompositeControl类的工厂模式

一切正常。除非据我所知，我必须将该控件添加回实际页面上的占位符控件。我到处寻找例子，找到了一个几乎可以工作的例子，希望它只在第一次回发时起作用

我在这里创建了一个示例，我将在这里发布所有代码

我的网页上的代码，这里最重要的是我想在OnInit上，我试图将控件添加回占位符，我想这可能是我做错的地方

using SampleControls;

public partial class Test : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            //Setup First Control
            Session.Clear();
            BaseCompositeControl ltb = new LabelTextBox();
            PlaceHolder1.Controls.Add(ltb);
            Session.Add("Control", ltb);
        }
    }

    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        // Check if the post back and recreate the control
        if (IsPostBack)
        {
            int c = this.Form.Controls.Count;
            for (int i = 0; i < Session.Count; i++)
            {
                if (Session[i].ToString().Contains("Control"))
                {
                    this.PlaceHolder1.Controls.Add((BaseCompositeControl)(Session[i]));
                }
            }
        }
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        //Get Postback Date
        BaseCompositeControl oltb = (BaseCompositeControl)this.PlaceHolder1.Controls[0];
        lblPstBck.Text = oltb.Text;

        this.PlaceHolder1.Controls.Clear();
        Session.Clear();

        //Load next Control
        BaseCompositeControl ltb = new LabelCheckBox();
        PlaceHolder1.Controls.Add(ltb);
        Session.Add("Control", ltb);

    }
}

文本框控件

public class LabelCheckBox : BaseCompositeControl
{
    protected CheckBox _CheckBox;

    public override string Text
    {
        get
        {
            EnsureChildControls();
            return _CheckBox.Checked.ToString(); ;
        }
        set
        {
            EnsureChildControls();
            _CheckBox.Checked = Convert.ToBoolean(value);
        }
    }
    protected override void CreateControlHierarchy()
    {
        _CheckBox = new CheckBox();
        Label l = new Label();
        // Configure controls
        l.Text = "Second Control";
        // Connect to the parent
        Controls.Add(l);
        Controls.Add(_CheckBox);
    }
}

    public class LabelTextBox : BaseCompositeControl
{
    protected TextBox _Text;
    public override string Text
    {
        get
        {
            EnsureChildControls();
            return _Text.Text;
        }
        set
        {
            EnsureChildControls();
            _Text.Text = value;
        }
    }
    protected override void CreateControlHierarchy()
    {
        Label l = new Label();
        _Text = new TextBox();
        // Configure controls
        l.Text = "First Control";
        // Connect to the parent
        Controls.Add(l);
        Controls.Add(_Text);
    }
}

复选框控件

public class LabelCheckBox : BaseCompositeControl
{
    protected CheckBox _CheckBox;

    public override string Text
    {
        get
        {
            EnsureChildControls();
            return _CheckBox.Checked.ToString(); ;
        }
        set
        {
            EnsureChildControls();
            _CheckBox.Checked = Convert.ToBoolean(value);
        }
    }
    protected override void CreateControlHierarchy()
    {
        _CheckBox = new CheckBox();
        Label l = new Label();
        // Configure controls
        l.Text = "Second Control";
        // Connect to the parent
        Controls.Add(l);
        Controls.Add(_CheckBox);
    }
}

    public class LabelTextBox : BaseCompositeControl
{
    protected TextBox _Text;
    public override string Text
    {
        get
        {
            EnsureChildControls();
            return _Text.Text;
        }
        set
        {
            EnsureChildControls();
            _Text.Text = value;
        }
    }
    protected override void CreateControlHierarchy()
    {
        Label l = new Label();
        _Text = new TextBox();
        // Configure controls
        l.Text = "First Control";
        // Connect to the parent
        Controls.Add(l);
        Controls.Add(_Text);
    }
}

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我很久以前问过这个问题

但我认为你应该这样做。对用户控件使用factory模式