回发后的多视图控件

Question

我正在尝试使用多视图控件。我首先创建一些视图并在 preinit 事件中添加一些标签。将它们添加到 (!isPostBack) 场景中的多视图中。 我想使用“下一个”和“上一个”按钮在视图之间导航。这就是我所做的：

protected void Page_PreInit(object sender, EventArgs e)
{
    if (IsPostBack)
    {
        MultiView1 = (MultiView)Session["multi"];            
    }
    else
    {
        View view1 = new View();
        View view2 = new View();
        View view3 = new View();
        Label l1 = new Label(); l1.Text = "1";
        Label l2 = new Label(); l2.Text = "2";
        Label l3 = new Label(); l3.Text = "3";
        view1.Controls.Add(l1);
        view2.Controls.Add(l2);
        view3.Controls.Add(l3);
        MultiView1.Views.Add(view1);
        MultiView1.Views.Add(view2);
        MultiView1.Views.Add(view3);
        MultiView1.ActiveViewIndex = 0;
        Session["multi"] = MultiView1;
    }
}    
protected void Page_Load(object sender, EventArgs e)
{        
}
protected void Button2_Click(object sender, EventArgs e)
{
    MultiView1.ActiveViewIndex++;
}
protected void Button1_Click(object sender, EventArgs e)
{
    MultiView1.ActiveViewIndex--;
}

这将不起作用，就好像多视图不保存其内容一样，并且不允许我将 activeviewindex 更改为大于 0 的值。我如何修改它以便我可以更改活动视图索引？

Answer 1

您每次都需要重新创建所有动态控件。如果将代码更改为以下内容，按钮应该可以工作：

    protected override void  OnInit(EventArgs e)
    {
        View view1 = new View();
        View view2 = new View();
        View view3 = new View();
        Label l1 = new Label();
        Label l2 = new Label();
        Label l3 = new Label();

        l1.Text = "1";
        l2.Text = "2";
        l3.Text = "3";

        view1.Controls.Add(l1);
        view2.Controls.Add(l2);
        view3.Controls.Add(l3);
        MultiView1.Views.Add(view1);
        MultiView1.Views.Add(view2);
        MultiView1.Views.Add(view3);
        MultiView1.ActiveViewIndex = 0;

        base.OnInit();
    }


    protected void Page_Load(object sender, EventArgs e)
    {
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        MultiView1.ActiveViewIndex++;
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        MultiView1.ActiveViewIndex--;
    }

我将代码移至 OnInit，因为由于某种原因，MultiView 尚未在 Pre_Init 上初始化。