VariableDispenser.LockForRead(String) 方法

定义

命名空间:

Microsoft.SqlServer.Dts.Runtime

程序集:

Microsoft.SqlServer.ManagedDTS.dll

将变量添加到要锁定用于只读访问的变量列表。

public:
 void LockForRead(System::String ^ variable);

public void LockForRead (string variable);

member this.LockForRead : string -> unit

Public Sub LockForRead (variable As String)

参数

variable

String

要添加到列表中以锁定用于只读访问的变量的名称。

示例

下面的代码示例创建一个 VariableDispenser 系统变量，并将两个系统变量添加到锁定以供读取的列表，并将一个系统变量添加到锁定以供写入的列表。 然后，调用该 GetVariables 变量来锁定集合中的所有三个变量，并释放列表并可用于新变量。

using System;  
using System.Collections.Generic;  
using System.Text;  
using Microsoft.SqlServer.Dts.Runtime;  

namespace Microsoft.SqlServer.SSIS.Sample  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            Package pkg = new Package();  
            Variables vars = null;  
            VariableDispenser variableDispenser = pkg.VariableDispenser;  
            variableDispenser.LockForRead("System::PackageName");  
            variableDispenser.LockForRead("System::OfflineMode");  
            variableDispenser.GetVariables(ref vars);             
            // Verify that the variable is locked before unlocking.  
            Console.WriteLine("Variables are locked? {0}", vars.Locked);  
            foreach (Variable myVar in vars)  
            {  
                Console.WriteLine("Name        {0}", myVar.Name);  
                Console.WriteLine("Description {0}", myVar.Description);  
                Console.WriteLine();  
            }  
            // Use Contains to determine whether indexing can be used.  
            Boolean pkgName = variableDispenser.Contains("PackageName");  
            String qName = variableDispenser.GetQualifiedName("PackageName");  
            Console.WriteLine("Contains is valid?       {0}", pkgName);  
            Console.WriteLine("Fully qualified name is: {0}", qName);  

            vars.Unlock();  

            Console.WriteLine("Variables are locked? {0}", vars.Locked);  
        }  
    }  
}  

Imports System  
Imports System.Collections.Generic  
Imports System.Text  
Imports Microsoft.SqlServer.Dts.Runtime  

Namespace Microsoft.SqlServer.SSIS.Sample  
    Class Program  
        Shared  Sub Main(ByVal args() As String)  
            Dim pkg As Package =  New Package()   
            Dim vars As Variables =  Nothing   
            Dim variableDispenser As VariableDispenser =  pkg.VariableDispenser   
            variableDispenser.LockForRead("System::PackageName")  
            variableDispenser.LockForRead("System::OfflineMode")  
            variableDispenser.GetVariables( vars)  
            ' Verify that the variable is locked before unlocking.  
            Console.WriteLine("Variables are locked? {0}", vars.Locked)  
            Dim myVar As Variable  
            For Each myVar In vars  
                Console.WriteLine("Name        {0}", myVar.Name)  
                Console.WriteLine("Description {0}", myVar.Description)  
                Console.WriteLine()  
            Next  
            ' Use Contains to determine whether indexing can be used.  
            Dim pkgName As Boolean =  variableDispenser.Contains("PackageName")   
            Dim qName As String =  variableDispenser.GetQualifiedName("PackageName")   
            Console.WriteLine("Contains is valid?       {0}", pkgName)  
            Console.WriteLine("Fully qualified name is: {0}", qName)  

            vars.Unlock()  

            Console.WriteLine("Variables are locked? {0}", vars.Locked)  
        End Sub  
    End Class  
End Namespace  

示例输出：

Variables are locked? True

Name OfflineMode

Description The offline mode currently set for the package

Name PackageName

Description The package name

Contains is valid? True

Fully qualified name is: System::PackageName

Variables are locked? False

注解

此方法在首次调用时创建一个列表，并将给定变量添加到列表中。 在后续调用中，变量将添加到现有列表中。 此方法实际上不会锁定变量。 创建所需变量的列表后，调用 GetVariables 以锁定此列表中找到的变量。 调用之前LockForWriteGetVariables可以进行任意数量的调用LockForRead。

备注

多个客户端可以同时获取变量上的只读锁。

若要在完成后清除成功的锁，请调用 Unlock。