ListView.SelectedValue 屬性
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
取得 ListView 控制項中選取之項目的資料索引鍵值。
public:
property System::Object ^ SelectedValue { System::Object ^ get(); };
[System.ComponentModel.Browsable(false)]
public object SelectedValue { get; }
[<System.ComponentModel.Browsable(false)>]
member this.SelectedValue : obj
Public ReadOnly Property SelectedValue As Object
屬性值
ListView 控制項中選取之項目的資料索引鍵值。
- 屬性
範例
下列範例示範如何在主要/詳細資料案例中使用第一個索引鍵欄位做為參數。 在 控制項中 ListView 選取專案時, SelectedValue 屬性會做為 PropertyNameControlParameter 物件的 。 這個參數物件會由第二 ListView 個控制項所系結的控制項使用 SqlDataSource 。
<%@ 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">
protected void CategoriesListView_OnItemDeleting(object sender, ListViewDeleteEventArgs e)
{
if (SubCategoriesGridView.Rows.Count > 0)
{
MessageLabel.Text = "You cannot delete a category that has sub-categories.";
e.Cancel = true;
}
}
protected void Page_Load()
{
MessageLabel.Text = String.Empty;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Subcategories List</title>
</head>
<body>
<form id="form1" runat="server">
<b>Categories</b>
<br />
<asp:Label ForeColor="Red" runat="server" ID="MessageLabel" /><br />
<asp:ListView runat="server"
ID="CategoriesListView"
OnItemDeleting="CategoriesListView_OnItemDeleting"
DataSourceID="CategoriesDataSource"
DataKeyNames="ProductCategoryID">
<LayoutTemplate>
<table runat="server" id="tblCategories"
cellspacing="0" cellpadding="1" width="440px" border="1">
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td style="width:40px">
<asp:LinkButton runat="server" ID="SelectCategoryButton"
Text="Select" CommandName="Select" />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr runat="server" style="background-color:#90EE90">
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td style="width:40px">
<asp:LinkButton runat="server" ID="SelectCategoryButton"
Text="Delete" CommandName="Delete" />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br />
<b>Subcategories</b>
<asp:GridView runat="server" ID="SubCategoriesGridView" Width="300px"
DataSourceID="SubCategoriesDataSource" DataKeyNames="ProductSubcategoryID"
AutoGenerateColumns="True" />
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="CategoriesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ProductCategoryID], [Name]
FROM Production.ProductCategory">
</asp:SqlDataSource>
<asp:SqlDataSource ID="SubCategoriesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ProductSubcategoryID], [Name]
FROM Production.ProductSubcategory
WHERE ProductCategoryID = @ProductCategoryID
ORDER BY [Name]">
<SelectParameters>
<asp:ControlParameter Name="ProductCategoryID" DefaultValue="0"
ControlID="CategoriesListView" PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>
</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">
Protected Sub CategoriesListView_OnItemDeleting(sender As Object, e As ListViewDeleteEventArgs)
If SubCategoriesGridView.Rows.Count > 0 Then
MessageLabel.Text = "You cannot delete a category that has sub-categories."
e.Cancel = True
End If
End Sub
Protected Sub Page_Load()
MessageLabel.Text = String.Empty
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Subcategories List</title>
</head>
<body>
<form id="form1" runat="server">
<b>Categories</b>
<br />
<asp:Label ForeColor="Red" runat="server" ID="MessageLabel" /><br />
<asp:ListView runat="server"
ID="CategoriesListView"
OnItemDeleting="CategoriesListView_OnItemDeleting"
DataSourceID="CategoriesDataSource"
DataKeyNames="ProductCategoryID">
<LayoutTemplate>
<table runat="server" id="tblCategories"
cellspacing="0" cellpadding="1" width="440px" border="1">
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr runat="server">
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td style="width:40px">
<asp:LinkButton runat="server" ID="SelectCategoryButton"
Text="Select" CommandName="Select" />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr runat="server" style="background-color:#90EE90">
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td style="width:40px">
<asp:LinkButton runat="server" ID="SelectCategoryButton"
Text="Delete" CommandName="Delete" />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br />
<b>Subcategories</b>
<asp:GridView runat="server" ID="SubCategoriesGridView" Width="300px"
DataSourceID="SubCategoriesDataSource" DataKeyNames="ProductSubcategoryID"
AutoGenerateColumns="True" />
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="CategoriesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ProductCategoryID], [Name]
FROM Production.ProductCategory">
</asp:SqlDataSource>
<asp:SqlDataSource ID="SubCategoriesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT [ProductSubcategoryID], [Name]
FROM Production.ProductSubcategory
WHERE ProductCategoryID = @ProductCategoryID
ORDER BY [Name]">
<SelectParameters>
<asp:ControlParameter Name="ProductCategoryID" DefaultValue="0"
ControlID="CategoriesListView" PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>
</form>
</body>
</html>
下列範例示範如何使用 SelectedValue 屬性來判斷索引鍵欄位的值。
<%@ 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">
protected void DepartmentsListView_SelectedIndexChanged(object sender, EventArgs e)
{
MessageLabel.Text = "The key value is " +
DepartmentsListView.SelectedValue.ToString() + ".";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView SelectedValue Example</title>
<style type="text/css">
.header
{
border: 1px solid #008080;
background-color: #008080;
color: White;
}
.item td { border: 1px solid #008080; }
.selection td
{
border: 1px solid #008080;
background-color: #7FFF00;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView SelectedValue Example</h3>
<asp:ListView runat="server"
ID="DepartmentsListView"
DataSourceID="DepartmentDataSource"
DataKeyNames="DepartmentID"
OnSelectedIndexChanged="DepartmentsListView_SelectedIndexChanged">
<LayoutTemplate>
<b>Department List</b>
<br />
<table width="500px" runat="server" id="tblDepartments">
<tr class="header" runat="server">
<th runat="server"> </th>
<th runat="server">Department Name</th>
<th runat="server">Group Name</th>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
</LayoutTemplate>
<ItemTemplate>
<tr class="item" runat="server">
<td>
<asp:LinkButton runat="server"
ID="SelectButton"
Text="Select"
CommandName="Select" />
</td>
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td>
<asp:Label runat="server" ID="GroupNameLabel" Text='<%#Eval("GroupName") %>' />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr class="selection" runat="server">
<td> </td>
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td>
<asp:Label runat="server" ID="GroupNameLabel" Text='<%#Eval("GroupName") %>' />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br/>
<asp:Label ID="MessageLabel"
ForeColor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="DepartmentDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT DepartmentID, Name, GroupName
FROM HumanResources.Department">
</asp:SqlDataSource>
</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">
Protected Sub DepartmentsListView_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
MessageLabel.Text = "The key value is " & _
DepartmentsListView.SelectedValue.ToString() & "."
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>ListView SelectedValue Example</title>
<style type="text/css">
.header
{
border: 1px solid #008080;
background-color: #008080;
color: White;
}
.item td { border: 1px solid #008080; }
.selection td
{
border: 1px solid #008080;
background-color: #7FFF00;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<h3>ListView SelectedValue Example</h3>
<asp:ListView runat="server"
ID="DepartmentsListView"
DataSourceID="DepartmentDataSource"
DataKeyNames="DepartmentID"
OnSelectedIndexChanged="DepartmentsListView_SelectedIndexChanged">
<LayoutTemplate>
<b>Department List</b>
<br />
<table width="500px" runat="server" id="tblDepartments">
<tr class="header" runat="server">
<th runat="server"> </th>
<th runat="server">Department Name</th>
<th runat="server">Group Name</th>
</tr>
<tr runat="server" id="itemPlaceholder" />
</table>
</LayoutTemplate>
<ItemTemplate>
<tr class="item" runat="server">
<td>
<asp:LinkButton runat="server"
ID="SelectButton"
Text="Select"
CommandName="Select" />
</td>
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td>
<asp:Label runat="server" ID="GroupNameLabel" Text='<%#Eval("GroupName") %>' />
</td>
</tr>
</ItemTemplate>
<SelectedItemTemplate>
<tr class="selection" runat="server">
<td> </td>
<td>
<asp:Label runat="server" ID="NameLabel" Text='<%#Eval("Name") %>' />
</td>
<td>
<asp:Label runat="server" ID="GroupNameLabel" Text='<%#Eval("GroupName") %>' />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<br/>
<asp:Label ID="MessageLabel"
ForeColor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the AdventureWorks sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:SqlDataSource ID="DepartmentDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
SelectCommand="SELECT DepartmentID, Name, GroupName
FROM HumanResources.Department">
</asp:SqlDataSource>
</form>
</body>
</html>
備註
DataKeyNames屬性可以設定為以逗號分隔的功能變數名稱清單,代表資料來源的主鍵。 如果已設定 ListView ,控制項就會使用指定欄位或欄位的值,自動為控制項中的每個專案建立 DataKey 物件。 然後,物件 DataKey 會新增至控制項的 DataKeys 集合。
一般而言, DataKeys 屬性是用來取得 DataKey 控制項中特定資料項目的 ListView 物件。 不過,如果您想要只 DataKey 取得目前選取之專案的物件,您可以使用 SelectedDataKey 屬性做為快捷方式。 您也可以使用 SelectedValue 屬性,直接判斷所選項目第一個索引鍵欄位的資料索引鍵值。
如果您要建立 物件,而且想要存取第一個 ControlParameter 欄位以外的索引鍵欄位,請使用 SelectedDataKey 屬性。 如需範例,請參閱 SelectedDataKey 屬性。
適用於
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