DataKey.Value 属性
定义
重要
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获取 DataKey 对象中索引 0 位置的键字段值。
public:
virtual property System::Object ^ Value { System::Object ^ get(); };public virtual object Value { get; }member this.Value : objPublic Overridable ReadOnly Property Value As Object属性值
DataKey 对象中索引 0 位置的键字段值。
示例
下面的代码示例演示如何使用 Value 属性来确定记录的主键值。
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void CustomerDetailsView_DataBound(Object sender, EventArgs e)
{
// Get the DataKey object for the current record.
DataKey key = CustomerDetailsView.DataKey;
// Display the value of the key field.
MessageLabel.Text = "The key field value for the displayed record is " +
key.Value.ToString() + ".";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DataKey Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataKey Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
datakeynames="CustomerID"
allowpaging="true"
ondatabound="CustomerDetailsView_DataBound"
runat="server">
</asp:detailsview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</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">
<script runat="server">
Sub CustomerDetailsView_DataBound(ByVal sender As Object, ByVal e As EventArgs) Handles CustomerDetailsView.DataBound
' Get the DataKey object for the current record.
Dim key As DataKey = CustomerDetailsView.DataKey
' Display the value of the key field.
MessageLabel.Text = "The key field value for the displayed record is " & _
key.Value.ToString() & "."
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DataKey Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataKey Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
datakeynames="CustomerID"
allowpaging="true"
runat="server">
</asp:detailsview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
注解
可以使用 Value 属性作为快捷方式来确定对象中索引 0 处键字段的值，而不是使用 Item[] 或 Values 属性从 DataKey 对象中DataKey检索键字段值。 当记录只有一个键字段时，此属性通常用于确定记录的键字段值。
注意
DataKey如果 对象不包含任何键字段，null则返回 。
