c# - ASP.NET 中的两种数据绑定(bind)方式

Question

假设我们有一个对象

class Entity
{
    public string ID {get; set;}
    public string Name {get; set;}
}

我想将属性绑定(bind)到页面上的两个文本框，如下所示:

<asp:FormView ID="FormView" runat="server">
  <ItemTemplate>
    <asp:textbox ID="TextId" Text='<%# Bind("ID") %>'/>
    <asp:textbox ID="TextId" Text='<%# Bind("Name") %>'/>
  </ItemTemplate>
</asp:FormView>

然后在代码后面写这个

public EntityObject
{
    get { return ViewState["Entity"] as Entity; }
    set { ViewState["Entity"] = value; }
}

protected override void OnInit(EventArgs e)
{
    if (EntityObject== null)
        EntityObject= new EntityObject();

    FormView.DataSource = new[] { EntityObject };
    FormView.DataBind();
    base.OnInit(e);
}

当我在文本框中输入值时，我希望 EntityObject 在 PostBack 后重新加载页面时在属性中具有这些值，但属性始终为 null。

Answer 1

遗憾的是，ASP.NET 不支持双向绑定(bind)到 .net 对象...相反，您可以在每次回发时使用“手动绑定(bind)”之类的东西(这里的 AddIncomeSources 是 RepeaterControl)

public List<Income> AdditionalIncomeList 
{
    get { return ViewState["AdditionalIncome"] as List<Income>; }
    set { ViewState["AdditionalIncome"] = value; }
} 

foreach (RepeaterItem item in AddIncomeSources.Items)
{
    var amount = (TextBox)item.Controls.Cast<Control>().First(c => c.ID == "Amount");
    var document = (DropDownList)item.Controls.Cast<Control>().First(c => c.ID == "Document");
    AdditionalIncomeList[item.ItemIndex].Amount = amount.Text.ToDouble();
    AdditionalIncomeList[item.ItemIndex].IncomeDocument = document.SelectedValue;
}

AddIncomeSources.DataSource = AdditionalIncomeList;
AddIncomeSources.DataBind();