了解ASP.NET的eval（）和bind（） [英] Understanding ASP.NET Eval() and Bind()
问题描述
谁能告诉我一些绝对最小的ASP.NET code理解的eval（）和绑定（）？
Can anyone show me some absolutely minimal ASP.NET code to understand Eval() and Bind()?
这是最好的，如果你给我提供两个独立的code-片段，也可以是网络链接。
It is best if you provide me with two separate code-snippets or may be web-links.
推荐答案
有关只读控制它们是相同的。对于2路数据绑定，使用中要更新数据源，插入等具有声明式数据绑定，你需要使用绑定。
For read-only controls they are the same. For 2 way databinding, using a datasource in which you want to update, insert, etc with declarative databinding, you'll need to use Bind.
想象一下，例如一个GridView与的ItemTemplate 和 EditItemTemplate中。如果您在的ItemTemplate ，那里使用绑定或评估将没有差别。如果您在使用评估的 EditItemTemplate中，该值将不能被传递到更新的
Imagine for example a GridView with a ItemTemplate and EditItemTemplate. If you use Bind or Eval in the ItemTemplate, there will be no difference. If you use Eval in the EditItemTemplate, the value will not be able to be passed to the Update method of the DataSource that the grid is bound to.
更新：我想出了这个例子：
UPDATE: I've come up with this example:
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Data binding demo</title>
</head>
<body>
<form id="form1" runat="server">
<asp:GridView
ID="grdTest"
runat="server"
AutoGenerateEditButton="true"
AutoGenerateColumns="false"
DataSourceID="mySource">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<%# Eval("Name") %>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox
ID="edtName"
runat="server"
Text='<%# Bind("Name") %>'
/>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</form>
<asp:ObjectDataSource
ID="mySource"
runat="server"
SelectMethod="Select"
UpdateMethod="Update"
TypeName="MyCompany.CustomDataSource" />
</body>
</html>
和这里是充当目标数据源的自定义类的定义：
And here's the definition of a custom class that serves as object data source:
public class CustomDataSource
{
public class Model
{
public string Name { get; set; }
}
public IEnumerable<Model> Select()
{
return new[]
{
new Model { Name = "some value" }
};
}
public void Update(string Name)
{
// This method will be called if you used Bind for the TextBox
// and you will be able to get the new name and update the
// data source accordingly
}
public void Update()
{
// This method will be called if you used Eval for the TextBox
// and you will not be able to get the new name that the user
// entered
}
}
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