TreeNodeBinding.ValueField 属性
定义
获取或设置数据源中字段的名称,该字段将绑定到 Value 对象将应用到的 TreeNode 对象的 TreeNodeBinding 属性。Gets or sets the name of the field from the data source to bind to the Value property of a TreeNode object to which the TreeNodeBinding object is applied.
public:
property System::String ^ ValueField { System::String ^ get(); void set(System::String ^ value); };
[System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public string ValueField { get; set; }
[System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public string ValueField { get; set; }
[<System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.ValueField : string with get, set
[<System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.ValueField : string with get, set
Public Property ValueField As String
属性值
要绑定到 Value 对象应用到的 TreeNode 对象的 TreeNodeBinding 属性的字段名称。The name of the field to bind to the Value property of a TreeNode object to which the TreeNodeBinding object is applied. 默认值为空字符串 (""),表示尚未设置 ValueField 属性。The default is an empty string (""), which indicates that the ValueField property is not set.
- 属性
示例
本部分包含两个代码示例。This section contains two code examples. 第一个代码示例演示如何使用 ValueField 属性指定要绑定到对象所应用到的对象的属性的 XML 元素的属性 Value TreeNode TreeNodeBinding 。The first code example demonstrates how to use the ValueField property to specify which attribute of an XML element to bind to the Value property of a TreeNode object to which the TreeNodeBinding object is applied. 第二个代码示例提供了第一个代码示例的示例 XML 数据。The second code example provides sample XML data for the first code example.
下面的示例演示如何使用 ValueField 属性指定要绑定到对象所 Value 应用到的对象的属性的 XML 元素的特性 TreeNode TreeNodeBinding 。The following example demonstrates how to use the ValueField property to specify which attribute of an XML element to bind to the Value property of a TreeNode object to which the TreeNodeBinding object is applied. 若要使此示例正常工作,必须将示例 XML 数据(在此代码示例之后提供)复制到名为 Booklist.xml 的文件中。For this example to work correctly, you must copy the sample XML data, provided after this code example, to a file named Booklist.xml.
<%@ 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>TreeViewBinding Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeViewBinding Example</h3>
<!-- Set the TextField, ImageUrlField, NavigateUrlField, -->
<!-- ValueField, and ToolTipField properties of a -->
<!-- TreeNodeBinding object declaratively. -->
<asp:TreeView id="BookTreeView"
DataSourceID="BookXmlDataSource"
Target="_blank"
runat="server">
<DataBindings>
<asp:TreeNodeBinding DataMember="Books"
Depth="0"
TextField="Text"/>
<asp:TreeNodeBinding DataMember="Book"
Depth="1"
TextField="Text"
ImageUrlField="Image"
ImageToolTipField="ImageToolTip"
NavigateUrlField="Nav"
ValueField="Value"
ToolTipField="Tip"/>
<asp:TreeNodeBinding DataMember="Description"
Depth="2"
TextField="Text"/>
<asp:TreeNodeBinding DataMember="Price"
Depth="2"
TextField="Value"/>
</DataBindings>
</asp:TreeView>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Booklist.xml"
runat="server">
</asp:XmlDataSource>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!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>TreeViewBinding Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeViewBinding Example</h3>
<!-- Set the TextField, ImageUrlField, NavigateUrlField, -->
<!-- ValueField, and ToolTipField properties of a -->
<!-- TreeNodeBinding object declaratively. -->
<asp:TreeView id="BookTreeView"
DataSourceID="BookXmlDataSource"
Target="_blank"
runat="server">
<DataBindings>
<asp:TreeNodeBinding DataMember="Books"
Depth="0"
TextField="Text"/>
<asp:TreeNodeBinding DataMember="Book"
Depth="1"
TextField="Text"
ImageUrlField="Image"
ImageToolTipField="ImageToolTip"
NavigateUrlField="Nav"
ValueField="Value"
ToolTipField="Tip"/>
<asp:TreeNodeBinding DataMember="Description"
Depth="2"
TextField="Text"/>
<asp:TreeNodeBinding DataMember="Price"
Depth="2"
TextField="Value"/>
</DataBindings>
</asp:TreeView>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Booklist.xml"
runat="server">
</asp:XmlDataSource>
</form>
</body>
</html>
下面的代码示例提供了前面的代码示例的示例 XML 数据。The following code example provides sample XML data for the preceding code example.
<Books Text="Books List">
<Book Text="Book Title One"
Value="1"
Image="Bookimage1.jpg"
ImageToolTip="Book 1 Photo"
Nav="http://www.microsoft.com"
Tip="Book Title 1">
<Description Text="Book Description">
</Description>
<Price Value="$1.99">
</Price>
<Author Text="Author Name"
Value="LastName"
Image="Authorimage1.jpg"
Nav="http://www.microsoft.com"
Tip="Author Name">
</Author>
</Book>
<Book Text="Book Title Two"
Value="2"
Image="Bookimage2.jpg"
ImageToolTip="Book 2 Photo"
Nav="http://www.microsoft.com"
Tip="Click Me">
<Description Text="Book Description">
</Description>
<Price Value="$2.99">
</Price>
<Author Text="Author Name"
Value="LastName"
Image="Authorimage2.jpg"
Nav="http://www.microsoft.com"
Tip="Author Name">
</Author>
</Book>
</Books>
注解
将 TreeView 控件绑定到数据源时,请使用 ValueField 属性指定要绑定到对象的属性的字段名称 Value TreeNode 。When the TreeView control is bound to a data source, use the ValueField property to specify the field name to bind to the Value property of a TreeNode object. 此绑定关系会影响 TreeNode 应用对象的所有对象 TreeNodeBinding 。This binding relationship affects all TreeNode objects to which the TreeNodeBinding object is applied. Value属性用于对属性进行补充, Text 方法是存储与应用对象的节点关联的任何附加数据 TreeNodeBinding 。The Value property is used to supplement the Text property by storing any additional data associated with the node to which the TreeNodeBinding object is applied. 此值不会显示在控件中,通常用于存储用于处理回发事件的数据。This value is not displayed in the control and is commonly used to store data for handling postback events.
备注
可以 ValueField 通过 Value 直接设置每个节点的属性,来有选择地重写属性。You can selectively override the ValueField property by setting the Value property of each node directly.
ValueField Value TreeNode 您可以通过设置属性,将属性设置 Value 为固定值,而不是使用属性将对象的属性绑定到字段 Value 。Instead of using the ValueField property to bind the Value property of a TreeNode object to an field, you can set the Value property to a fixed value by setting the Value property.
备注
如果数据源包含多个字段,则必须首先设置 Depth 或 DataMember 属性,或同时设置这两个属性,才能绑定到相应的字段。If the data source contains multiple fields, you must first set the Depth or DataMember property, or both properties in order to bind to the appropriate field.
此属性的值存储在视图状态中。The value of this property is stored in view state.