Listview更改适用于第二次发布后？

Question

我有一个列表视图和按钮列表视图，按钮单击我想要添加InsertItemTemplate中定义的“插入”行。问题是当我点击按钮，这一行被添加（我知道这是因为当做任何回发后此行真的显示），但没有显示/呈现。所以问题是：为什么这个改变不适用于第一次回发 - 按钮点击？这里是我的代码：

编辑：
全代码隐藏：

protected void Page_Load(object sender, EventArgs e) 
    {       
     if (!IsPostBack) 
     { 


      ListItem ByName = new ListItem("By name", "Name"); 
      ListItem ByPhone = new ListItem("By phone", "Phone"); 
      ListItem ByEmail = new ListItem("By email", "Email"); 

      FilterTypeDDL.Items.Add(ByName); 
      FilterTypeDDL.Items.Add(ByPhone); 
      FilterTypeDDL.Items.Add(ByEmail); 
      FilterTypeDDL.DataBind(); 
     } 
    } 

    //protected void ListView_ItemCommand(object sender, ListViewCommandEventArgs e) 
    //{    
     //switch (e.CommandName) 
     //{ 
      //case "EditItem":      
      // break; 

      //case "InsertItem": 
      // if (Page.IsValid) 
      // { 
      //  string NameTxt = ((TextBox)(ListView.InsertItem.FindControl("NameTextBox"))).Text.Trim(); 
      //  string PhoneTxt = ((TextBox)(ListView.InsertItem.FindControl("PhoneTextBox"))).Text.Trim(); 
      //  string EmailTxt = ((TextBox)(ListView.InsertItem.FindControl("EmailTextBox"))).Text.Trim(); 
      //  DAORestaurant.InsertRestaurant(NameTxt, PhoneTxt, EmailTxt); 


      //  ListView.InsertItemPosition = InsertItemPosition.None; 
      //  ListView.DataSource = DAORestaurant.GetRestaurants(); 
      //  ListView.DataBind(); 
      //  break; 
      // } 
      // break; 

      //case "CancelCreation": 
      // ListView.InsertItemPosition = InsertItemPosition.None; 
      // ListView.DataSource = DAORestaurant.GetRestaurants(); 
      // ListView.DataBind(); 
      // break; 

      //case "Articles": 
      // Session["Restaurant"] = e.CommandArgument.ToString(); 
      // Control ArticlesCtrl = LoadControl("~/Controls/Article.ascx"); 
      // ListViewItem Item = (ListViewItem)e.Item; 
      // Item.FindControl("CtrlPlaceHolder").Controls.Add(ArticlesCtrl); 
     //} 

    //} 

    protected void closeButton_Click(object sender, EventArgs e) 
    { 

    } 

    protected void newArticleButton_Click(object sender, EventArgs e) 
    { 

    } 

    protected void NewRestaurantBtn_Click(object sender, EventArgs e) 
    { 
     ListView.InsertItemPosition = InsertItemPosition.LastItem; 
     //SetDataSource(); 
     //ListView.DataBind();   
    } 

    protected void ValidateName(object source, ServerValidateEventArgs args) 
    { 
     string NameTxt = ((TextBox)(ListView.InsertItem.FindControl("NameTextBox"))).Text.Trim(); 
     args.IsValid = (NameTxt.Length > 2 && NameTxt.Length < 51); 
    } 

    protected void ValidateUniqueness(object source, ServerValidateEventArgs args) 
    { 
     string NameTxt = ((TextBox)(ListView.InsertItem.FindControl("NameTextBox"))).Text.Trim(); 
     args.IsValid = DAORestaurant.IsUnique(NameTxt); 
    } 

    protected void ValidatePhone(object source, ServerValidateEventArgs args) 
    { 
     string PhoneTxt = ((TextBox)(ListView.InsertItem.FindControl("PhoneTextBox"))).Text.Trim(); 
     Regex regex = new Regex(@"^\d{3}\s\d{3}\s\d{3}$"); 
     args.IsValid = regex.IsMatch(PhoneTxt); 
    } 

    protected void ValidateEmail(object source, ServerValidateEventArgs args) 
    { 
     string EmailTxt = ((TextBox)(ListView.InsertItem.FindControl("EmailTextBox"))).Text.Trim(); 
     Regex regex = new Regex(@"^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$"); 
     args.IsValid = regex.IsMatch(EmailTxt); 
    } 

    protected void ShowAllBtn_Click(object sender, EventArgs e) 
    {    
     Session["ALL"] = true; 
     ListView.DataSource = DAORestaurant.GetRestaurants(); 
     ListView.DataBind(); 
    } 

    protected void FilterBtn_Click(object sender, EventArgs e) 
    { 
     string filterType = FilterTypeDDL.SelectedValue; 
     string substring = StringTB.Text.Trim().ToUpper(); 
     Session["ALL"] = false; 
     Session["FilterType"] = filterType; 
     Session["Substring"] = substring; 


     ListView.DataSource = DAORestaurant.GetRestaurants(substring, filterType); 
     ListView.DataBind(); 
    } 

    protected void ListView_ItemEditing(object sender, ListViewEditEventArgs e) 
    { 
     ListView.EditIndex = e.NewEditIndex; 

     //SetDataSource(); 
     //ListView.DataBind(); 
    } 

    protected void ListView_ItemInserting(object sender, ListViewInsertEventArgs e) 
    { 

    } 

    protected void ListView_ItemCanceling(object sender, ListViewCancelEventArgs e) 
    { 
     if (e.CancelMode == ListViewCancelMode.CancelingInsert) 
     { 
      ListView.InsertItemPosition = InsertItemPosition.None; 
     } 
     else 
     { 
      ListView.EditIndex = -1;     
     } 

     //SetDataSource(); 
     //ListView.DataBind(); 
    } 

    private void SetDataSource() 
    { 
     if ((bool)Session["ALL"]) 
     { 
      ListView.DataSource = DAORestaurant.GetRestaurants(); 
     } 
     else 
     { 
      ListView.DataSource = DAORestaurant.GetRestaurants((string)Session["Substring"], (string)Session["FilterType"]); 
     }    
    } 

注释掉的代码是什么我之前使用，从来就切换到你现在可以看到的，但问题仍然存在。只有当我在每个事件中取消注释这2条注释行时，这些更改才会立即生效，但我知道我不能多次使用这种方法，而且它甚至不应该存在。

Answer 1

由于执行顺序。尝试在Page_Load事件设置它：

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (IsPostBack && 
     !string.IsNullOrEmpty(Request.Form[NewRestaurantBtn.ClientID])) 
    { 
     ListView.InsertItemPosition = InsertItemPosition.LastItem; 
    } 
}