ControlCollection.SyncRoot 屬性

定義

命名空間:

System.Web.UI

組件:

System.Web.dll

取得可用來對控制項集合進行同步 (Synchronize) 存取的物件。

public:
 property System::Object ^ SyncRoot { System::Object ^ get(); };

public object SyncRoot { get; }

member this.SyncRoot : obj

Public ReadOnly Property SyncRoot As Object

屬性值

Object

用來同步處理集合的 Object。

實作

SyncRoot

範例

下列程式碼範例會建立方法，以列舉 ControlCollection 控制項 myButton 的 Button 集合。 建立列舉值時， IsSynchronized 會檢查 屬性，以查看作業是否為安全線程，如果不是，則會 SyncRoot 使用 屬性來取得物件，讓作業執行緒安全。 當列舉完成時，屬性的值 IsReadOnly 會寫入為 Text 包含頁面上控制項的 Label 屬性。

// Create a method that enuberates through a 
// button//s ControlCollection in a thread-safe manner.  
public void ListControlCollection(object sender, EventArgs e)
{
   IEnumerator myEnumerator = myButton.Controls.GetEnumerator();

   // Check the IsSynchronized property. If False,
   // use the SyncRoot method to get an object that 
   // allows the enumeration of all controls to be 
   // thread safe.
   if (myButton.Controls.IsSynchronized == false)
   {
       lock (myButton.Controls.SyncRoot)
       {
           while (myEnumerator.MoveNext())
           {

               Object myObject = myEnumerator.Current;

               LiteralControl childControl = (LiteralControl)myEnumerator.Current;
               Response.Write("<b><br /> This is the  text of the child Control  </b>: " +
                              childControl.Text);
           }
           msgReadOnly.Text = myButton.Controls.IsReadOnly.ToString();
       }
   }       
}

' Create a method that enuberates through a 
' button's ControlCollection in a thread-safe manner.  
Public Sub ListControlCollection(sender As Object, e As EventArgs)
   Dim myEnumerator As IEnumerator = myButton.Controls.GetEnumerator()

   ' Check the IsSynchronized property. If False,
   ' use the SyncRoot method to get an object that 
   ' allows the enumeration of all controls to be 
   ' thread safe.
   If myButton.Controls.IsSynchronized = False Then
     SyncLock myButton.Controls.SyncRoot
       While (myEnumerator.MoveNext())

       Dim myObject As Object  = myEnumerator.Current
           
         Dim childControl As LiteralControl = CType(myEnumerator.Current, LiteralControl)
         Response.Write("<b><br /> This is the  text of the child Control  </b>: " & _
                        childControl.Text)
       End While
      msgReadOnly.Text = myButton.Controls.IsReadOnly.ToString()
      
      End SyncLock
   End If       
 End Sub

另請參閱

• Controls