DataKeyArray DataKeyArray DataKeyArray DataKeyArray Class

定义

表示 DataKey 对象集合。Represents a collection of DataKey objects. 此类不能被继承。This class cannot be inherited.

public ref class DataKeyArray sealed : System::Collections::ICollection, System::Web::UI::IStateManager
public sealed class DataKeyArray : System.Collections.ICollection, System.Web.UI.IStateManager
type DataKeyArray = class
    interface ICollection
    interface IEnumerable
    interface IStateManager
Public NotInheritable Class DataKeyArray
Implements ICollection, IStateManager
继承
DataKeyArrayDataKeyArrayDataKeyArrayDataKeyArray
实现

示例

下面的代码示例演示如何使用索引器DataKey DataKeyArray从集合中检索对象。The following code example demonstrates how to use the indexer to retrieve a DataKey object from a DataKeyArray collection.


<%@ 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 CustomerGridView_DataBound(Object sender, EventArgs e)
  {           
    // Use the indexer to retrieve the DataKey object for the 
    // first record.
    DataKey key = CustomerGridView.DataKeys[0];

    // Display the value of the primary key for the first
    // record displayed in the GridView control.
    MessageLabel.Text = "The primary key of the first record displayed is " +
      key.Value.ToString() + ".";
  }

  void CopyArray_Click(Object sender, EventArgs e)
  {
      DataKeyArray theKeys = CustomerGridView.DataKeys;
      DataKey[] myNewArray = new DataKey[theKeys.Count];
      theKeys.CopyTo(myNewArray, 0);
      Label2.Visible = true;

      // Display first page key values from the new array.
      for (int i = 0; i < myNewArray.Length; i++)
      {
          Label2.Text += "<br />" + myNewArray[i].Value;
      }

  }

</script>

<html  >

  <head id="Head1" runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>DataKeyArray Example</h3>

        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          ondatabound="CustomerGridView_DataBound" 
          runat="server">

        </asp:gridview>

        <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="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthwindConnectionString %>" 
          runat="server"/>

        <asp:Button ID="CopyArray" 
            runat="server" 
            Text="Copy DataKeyArray to Array" 
            OnClick="CopyArray_Click" />

        <br />

        <asp:label id="Label2"
          runat="server"
          Visible="false"  
          Text="First page of Copied Array Key Values" />


      </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 CustomerGridView_DataBound(ByVal sender As Object, ByVal e As EventArgs) Handles CustomerGridView.DataBound
          
    ' Use the indexer to retrieve the DataKey object for the 
    ' first record.
    Dim key As DataKey = CustomerGridView.DataKeys(0)

    ' Display the value of the primary key for the first
    ' record displayed in the GridView control.
    MessageLabel.Text = "The primary key of the first record displayed is " & _
      key.Value.ToString() & "."
  
    End Sub
    
    Sub CopyArray_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim theKeys As DataKeyArray = CustomerGridView.DataKeys
        Dim myNewArray(theKeys.Count - 1) As DataKey
        theKeys.CopyTo(myNewArray, 0)
        Label2.Visible = True

        ' Display first page key values from the new array.  
        For i As Integer = 0 To myNewArray.Length - 1
            Label2.Text &= "<br />" & myNewArray(i).Value
        Next i

    End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head id="Head1" runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          runat="server">
            
        </asp:gridview>
        
        <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="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>

        <asp:Button ID="CopyArray" 
            runat="server" 
            Text="Copy DataKeyArray to Array" 
            OnClick="CopyArray_Click" />

        <br />

        <asp:label id="Label2"
          runat="server"
          Visible="false"  
          Text="First page of Copied Array Key Values" />
            
      </form>
  </body>
</html>

下面的代码示例演示如何循环访问DataKeyArray集合。The following code example demonstrates how to iterate through a DataKeyArray collection.


<%@ 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 CustomerGridView_DataBound(Object sender, EventArgs e)
  {    
    // Display the value of the primary key for each
    // record in the GridView control.
    MessageLabel.Text = "The primary key of each record displayed are: <br/><br/>";

    foreach (DataKey key in CustomerGridView.DataKeys)
    {
       MessageLabel.Text += key.Value.ToString() + "<br/>";
    }
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          ondatabound="CustomerGridView_DataBound" 
          runat="server">
            
        </asp:gridview>
        
        <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="CustomerDataSource"
          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 CustomerGridView_DataBound(ByVal sender As Object, ByVal e As EventArgs) Handles CustomerGridView.DataBound
    
    ' Display the value of the primary key for each
    ' record in the GridView control.
    MessageLabel.Text = "The primary key of each record displayed are: <br/><br/>"

    Dim key As DataKey
    For Each key In CustomerGridView.DataKeys
    
      MessageLabel.Text += key.Value.ToString() + "<br/>"
      
    Next
    
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          runat="server">
            
        </asp:gridview>
        
        <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="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

注解

类用于存储和管理DataKey对象集合。 DataKeyArrayThe DataKeyArray class is used to store and manage a collection of DataKey objects. DataKey对象表示数据绑定控件中的记录的主键。A DataKey object represents the primary key of a record in a data-bound control. 通常, 显示多个记录的数据绑定控件 (如GridView控件) DataKeyArray使用对象存储DataKey控件中显示的记录的对象。In general, data-bound controls that display multiple records (such as the GridView control) use a DataKeyArray object to store the DataKey objects for the records displayed in the control.

DataKeyArray类支持多种方法来访问集合中的项:The DataKeyArray class supports several ways to access the items in the collection:

  • 使用索引器直接从集合中DataKey检索特定的从零开始的索引处的对象。 Item[Int32]Use the Item[Int32] indexer to directly retrieve a DataKey object from the collection at a specific zero-based index.

  • GetEnumerator使用方法检索可用于循环访问集合的枚举器。Use the GetEnumerator method to retrieve an enumerator that can be used to iterate through the collection.

  • CopyTo使用方法将集合中的项复制到数组中, 然后可以使用该数组访问集合中的项。Use the CopyTo method to copy the items in the collection into an array, which can then be used to access the items in the collection.

若要确定集合中的总项数, 请使用Count属性。To determine the total number of items in the collection, use the Count property.

构造函数

DataKeyArray(ArrayList) DataKeyArray(ArrayList) DataKeyArray(ArrayList) DataKeyArray(ArrayList)

初始化 DataKeyArray 类的新实例。Initializes a new instance of the DataKeyArray class.

属性

Count Count Count Count

获取集合中的项数。Gets the number of items in the collection.

IsReadOnly IsReadOnly IsReadOnly IsReadOnly

获取一个值,该值指示是否可以修改集合中的项。Gets a value indicating whether the items in the collection can be modified.

IsSynchronized IsSynchronized IsSynchronized IsSynchronized

获取指示 DataKeyArray 集合是否已同步(线程安全)的值。Gets a value indicating whether the DataKeyArray collection is synchronized (thread safe).

Item[Int32] Item[Int32] Item[Int32] Item[Int32]

从集合中获取指定索引处的 DataKey 对象。Gets the DataKey object from the collection at the specified index.

SyncRoot SyncRoot SyncRoot SyncRoot

获取用于同步访问集合的对象。Gets the object used to synchronize access to the collection.

方法

CopyTo(DataKey[], Int32) CopyTo(DataKey[], Int32) CopyTo(DataKey[], Int32) CopyTo(DataKey[], Int32)

将此集合中的所有项复制到 DataKey 对象的指定数组(从数组中的指定索引位置开始)。Copies all the items from this collection to the specified array of DataKey objects, starting at the specified index in the array.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

返回一个包含集合中的所有 DataKey 对象的枚举数。Returns an enumerator that contains all DataKey objects in the collection.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

作为默认哈希函数。Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

获取当前实例的 TypeGets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

返回表示当前对象的字符串。Returns a string that represents the current object.

(Inherited from Object)

显式界面实现

ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32)

将此集合中的所有项复制到指定的 Array(从 Array 中的指定索引位置开始)。Copies all the items from this collection to the specified Array, starting at the specified index in the Array.

IStateManager.IsTrackingViewState IStateManager.IsTrackingViewState IStateManager.IsTrackingViewState IStateManager.IsTrackingViewState

获取一个值,该值指示 DataKeyArray 对象是否跟踪其视图状态更改。Gets a value indicating whether the DataKeyArray object is tracking its view-state changes.

IStateManager.LoadViewState(Object) IStateManager.LoadViewState(Object) IStateManager.LoadViewState(Object) IStateManager.LoadViewState(Object)

加载以前保存的 DataKeyArray 对象的视图状态。Loads the previously saved view state of the DataKeyArray object.

IStateManager.SaveViewState() IStateManager.SaveViewState() IStateManager.SaveViewState() IStateManager.SaveViewState()

保存 DataKeyArray 对象的当前视图状态。Saves the current view state of the DataKeyArray object.

IStateManager.TrackViewState() IStateManager.TrackViewState() IStateManager.TrackViewState() IStateManager.TrackViewState()

标记开始跟踪并将视图状态更改保存到 DataKeyArray 对象的起点。Marks the starting point at which to begin tracking and saving view-state changes to the DataKeyArray object.

扩展方法

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

IEnumerable 的元素强制转换为指定的类型。Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

根据指定类型筛选 IEnumerable 的元素。Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

启用查询的并行化。Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

IEnumerable 转换为 IQueryableConverts an IEnumerable to an IQueryable.

适用于

另请参阅