EnvironmentPermission.GetPathList 方法

获取所有具有指定 EnvironmentPermissionAccess 的环境变量。

**命名空间:**System.Security.Permissions
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
Public Function GetPathList ( _
    flag As EnvironmentPermissionAccess _
) As String
用法
Dim instance As EnvironmentPermission
Dim flag As EnvironmentPermissionAccess
Dim returnValue As String

returnValue = instance.GetPathList(flag)

public string GetPathList (
    EnvironmentPermissionAccess flag
)

public:
String^ GetPathList (
    EnvironmentPermissionAccess flag
)

public String GetPathList (
    EnvironmentPermissionAccess flag
)

public function GetPathList (
    flag : EnvironmentPermissionAccess
) : String

参数

• flag
  代表单一的环境变量访问类型的 EnvironmentPermissionAccess 值之一。

返回值

选定标志的环境变量列表（以分号分隔）。

异常

异常类型	条件
ArgumentException	flag 不是有效的 EnvironmentPermissionAccess 值。 - 或 - flag 为 AllAccess（表示多种类型的环境变量访问）或 NoAccess（不表示任何类型的环境变量访问）。

备注

使用此方法获取当前权限的状态。要想同时获取 Read 和 Write 权限状态，需要调用两次此方法。

提示

flag 参数限制为只能是 EnvironmentPermissionAccess 的值，这些值代表单一的环境变量访问类型。这些值为 Read 和 Write。flag 可接受的值不包括 NoAccess 和 AllAccess，它们不代表单一的环境变量访问类型。

示例

下面的代码示例演示 GetPathList 方法的用法。此代码示例摘自一个为 EnvironmentPermission 类提供的更大的示例。

Private Function SetGetPathListDemo() As Boolean 
    Try
        Console.WriteLine("********************************************************" + vbLf)
        Console.WriteLine("Creating an EnvironmentPermission with AllAccess rights for 'TMP'")
        Dim envPerm1 As New EnvironmentPermission(EnvironmentPermissionAccess.AllAccess, "TMP")
        Console.WriteLine("Adding 'TEMP' to the write access list, and 'windir' to the read access list.")
        envPerm1.AddPathList(EnvironmentPermissionAccess.Write, "TEMP")
        envPerm1.AddPathList(EnvironmentPermissionAccess.Read, "windir")
        Console.WriteLine("Read access list before SetPathList = " + envPerm1.GetPathList(EnvironmentPermissionAccess.Read))
        Console.WriteLine("Setting read access to 'TMP'")
        envPerm1.SetPathList(EnvironmentPermissionAccess.Read, "TMP")
        Console.WriteLine("Read access list after SetPathList = " + envPerm1.GetPathList(EnvironmentPermissionAccess.Read))
        Console.WriteLine("Write access list = " + envPerm1.GetPathList(EnvironmentPermissionAccess.Write))
        Console.WriteLine("Write access environment variables = " + envPerm1.GetPathList(EnvironmentPermissionAccess.AllAccess))
    Catch e As ArgumentException
        ' EnvironmentPermissionAccess.AllAccess cannot be used as a parameter for GetPathList.
        Console.WriteLine("An ArgumentException occurred as a result of using AllAccess. " + _
        " This property cannot be used as a parameter in GetPathList, because it represents " + _
        "more than one type of environment variable : " + vbLf + e.Message)
    End Try
    
    Return True

End Function 'SetGetPathListDemo

private bool SetGetPathListDemo()
{
    try
    {
        Console.WriteLine("********************************************************\n");
        Console.WriteLine("Creating an EnvironmentPermission with AllAccess rights for 'TMP'");
        EnvironmentPermission envPerm1 = new EnvironmentPermission(EnvironmentPermissionAccess.AllAccess, "TMP");
        Console.WriteLine("Adding 'TEMP' to the write access list, and 'windir' to the read access list.");
        envPerm1.AddPathList(EnvironmentPermissionAccess.Write, "TEMP");
        envPerm1.AddPathList(EnvironmentPermissionAccess.Read, "windir");
        Console.WriteLine("Read access list before SetPathList = "
            + envPerm1.GetPathList(EnvironmentPermissionAccess.Read));
        Console.WriteLine("Setting read access to 'TMP'");
        envPerm1.SetPathList(EnvironmentPermissionAccess.Read, "TMP");
        Console.WriteLine("Read access list after SetPathList = "
            + envPerm1.GetPathList(EnvironmentPermissionAccess.Read));
        Console.WriteLine("Write access list = " + envPerm1.GetPathList(EnvironmentPermissionAccess.Write));
        Console.WriteLine("Write access environment variables = "
            + envPerm1.GetPathList(EnvironmentPermissionAccess.AllAccess));
    }
    catch (ArgumentException e)
    {
        // EnvironmentPermissionAccess.AllAccess cannot be used as a parameter for GetPathList.
        Console.WriteLine("An ArgumentException occurred as a result of using AllAccess. "
            + " This property cannot be used as a parameter in GetPathList, because it represents "
            + "more than one type of environment variable : \n" + e);
    }

    return true;
}

平台

Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

EnvironmentPermission 类
EnvironmentPermission 成员
System.Security.Permissions 命名空间