不能理解FormView1中使用DataSource绑定数据源出现的问题

悬赏园豆：30 [已关闭问题]

使用MS Web控件时总是会碰到这样那样的问题,由于对原理不是很清楚。一下是我在使用DataSource做FormView1数据源遇到的问题。 前提 前台代码：       <div>         <asp:FormView ID="FormView1" runat="server" DataKeyNames="CategoryID"  OnItemCommand="FormView1_ItemCommand" OnItemUpdating="FormView1_ItemUpdating" OnItemUpdated="FormView1_ItemUpdated" OnModeChanging="FormView1_ModeChanging">             <EditItemTemplate>                 CategoryID:                 <asp:Label ID="CategoryIDLabel1" runat="server" Text='<%# Eval("CategoryID") %>'></asp:Label><br />                 CategoryName:                 <asp:TextBox ID="CategoryNameTextBox" runat="server" Text='<%# Bind("CategoryName") %>'></asp:TextBox><br />                 Description:                 <asp:TextBox ID="DescriptionTextBox" runat="server" Text='<%# Bind("Description") %>'></asp:TextBox><br />                 <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update"                     Text="更新"></asp:LinkButton>                 <asp:LinkButton ID="UpdateCancelButton" runat="server" CausesValidation="False" CommandName="Cancel"                     Text="取消"></asp:LinkButton>                 <asp:Button ID="Button2" runat="server" Text="更新" CausesValidation="true" CommandName="Update" />                 <asp:Button ID="Button3" runat="server" Text="取消" CausesValidation="false" CommandName="Cancel" />             </EditItemTemplate>             <ItemTemplate>                 CategoryID:                 <asp:Label ID="CategoryIDLabel" runat="server" Text='<%# Eval("CategoryID") %>'></asp:Label><br />                 CategoryName:                 <asp:Label ID="CategoryNameLabel" runat="server" Text='<%# Bind("CategoryName") %>'></asp:Label><br />                 Description:                 <asp:Label ID="DescriptionLabel" runat="server" Text='<%# Bind("Description") %>'></asp:Label><br />             </ItemTemplate>         </asp:FormView>     </div>         <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="更改成编辑状态" /> 后台代码： public class Category {     string _categoryID = string.Empty;       public string CategoryID     {         get { return _categoryID; }         set { _categoryID = value; }     }     string _categoryName = string.Empty;       public string CategoryName     {         get { return _categoryName; }         set { _categoryName = value; }     }     string _description = string.Empty;       public string Description     {         get { return _description; }         set { _description = value; }     }      public Category()      {            }    }    protected void Page_Load(object sender, EventArgs e)     {         //if (!IsPostBack)         //{             this.FormView1.DataSource = GetDataSourse();             this.FormView1.DataBind();        // }     }     protected void Button1_Click(object sender, EventArgs e)     {         this.FormView1.ChangeMode(FormViewMode.Edit);     }     protected void FormView1_ItemCommand(object sender, FormViewCommandEventArgs e)     {         Response.Write("FormView1_ItemCommand");     }     protected void FormView1_ItemUpdating(object sender, FormViewUpdateEventArgs e)     {         Response.Write("FormView1_ItemUpdating");     }       private IList<Category> GetDataSourse()     {         IList<Category> data = new List<Category>();         Category ct = new Category();         ct.CategoryID = "1";         ct.CategoryName = "PC";         ct.Description = "电脑";         data.Add(ct);         return data;     }     protected void FormView1_ItemUpdated(object sender, FormViewUpdatedEventArgs e)     {         Response.Write("FormView1_ItemUpdated");     }     protected void FormView1_ModeChanging(object sender, FormViewModeEventArgs e)     {         Response.Write("FormView1_ModeChanging"); }   问题： 1.               在编辑状态下同样是设置的CommandName的Button 和LinkButton 如果没有加if(!IsPostBack)判断，LinkButton将会预期触发ItemCommand，ItemUpdating事件，而Button不会。但在加有if(!IsPostBack)的情况下。Button 与LinkButton都会触发ItemCommand，ItemUpdating为什么？ 2.               ItemUpdated事件始终不被触发，为什么？ 3.               为什么每次是在两次点击“更改成编辑状态”按钮才能将FormView改变成编辑状态。 4.               为什么在使用DataSource数据源的情况下ComandName为Cancel是按钮需要处理ModeChanging事件，而在指定DataSourceID是他会自动回到DefaultModel状态。 5.               我如何能在更新和取消后回到DefaultModel状态？

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