FileDialogPermission.Intersect 方法

创建并返回一个权限，该权限是当前权限和指定权限的交集。

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

语法

声明
Public Overrides Function Intersect ( _
    target As IPermission _
) As IPermission
用法
Dim instance As FileDialogPermission
Dim target As IPermission
Dim returnValue As IPermission

returnValue = instance.Intersect(target)

public override IPermission Intersect (
    IPermission target
)

public:
virtual IPermission^ Intersect (
    IPermission^ target
) override

public IPermission Intersect (
    IPermission target
)

public override function Intersect (
    target : IPermission
) : IPermission

参数

• target
  要与当前权限相交的权限。它必须与当前权限属于同一类型。

返回值

一个新权限，它表示当前权限与指定权限的交集。如果交集为空，则此新权限为 空引用（在 Visual Basic 中为 Nothing）。

异常

异常类型	条件
ArgumentException	target 参数不是 空引用（在 Visual Basic 中为 Nothing），而且与当前权限不是同一类型。

备注

两个权限的交集是一个权限，用于描述它们共同描述的一套操作。只有同时通过两个原始权限的请求才能通过该交集。

示例

下面的代码示例旨在演示 Intersect 方法的行为，而不演示其用法。一般情况下，权限类的方法由安全性基础结构使用，而不在应用程序中使用。但是，下面的代码示例将演示在从您的代码执行该方法时，该方法将如何执行。有关完整的代码示例，请参见 FileDialogPermission 类。

Private Function IntersectDemo() As Boolean 
    Dim returnValue As Boolean = True
    
    fileDialogPerm3 = CType(fileDialogPerm1.Intersect(fileDialogPerm2), FileDialogPermission)
    If Not (fileDialogPerm3 Is Nothing) Then
        Console.WriteLine("The intersection of " + fileDialogPerm1.Access.ToString() + " and " _
        + fileDialogPerm2.Access.ToString() + " = " + CType(fileDialogPerm3, _
        FileDialogPermission).Access.ToString())
    Else
        Console.WriteLine("The intersection of " + fileDialogPerm1.Access.ToString() + " and " + _
        fileDialogPerm2.Access + " is null.")
    End If
    
    Return returnValue

End Function 'IntersectDemo

private bool IntersectDemo()
{
    bool returnValue = true;

    fileDialogPerm3 = (FileDialogPermission)fileDialogPerm1.Intersect(fileDialogPerm2);
    if (fileDialogPerm3 != null)
    {
        Console.WriteLine("The intersection of " + fileDialogPerm1.Access + 
            " and " + fileDialogPerm2.Access + " = " +
            ((FileDialogPermission)fileDialogPerm3).Access.ToString());
    }
    else
    {
        Console.WriteLine("The intersection of " + fileDialogPerm1.Access + 
            " and " + fileDialogPerm2.Access + " is null.");
    }
    
    return returnValue;
}

bool IntersectDemo()
{
    bool returnValue = true;
    FileDialogPermission^ fileDialogIdPerm1 = 
        gcnew FileDialogPermission(FileDialogPermissionAccess::Open );
    FileDialogPermission^ fileDialogIdPerm2 = 
        gcnew FileDialogPermission( FileDialogPermissionAccess::OpenSave );

    FileDialogPermission^ fileDialogIdPerm3 = 
        gcnew FileDialogPermission(PermissionState::None);

    //Console.WriteLine("\tfileDialogIdPerm2 = " +fileDialogIdPerm2.ToString());
    fileDialogIdPerm3 = dynamic_cast<FileDialogPermission^>(fileDialogIdPerm1->Intersect( fileDialogIdPerm2 ));
    if ( fileDialogIdPerm3 != nullptr )
    {
        Console::WriteLine( "The intersection of {0} and {1} = {2}", 
            fileDialogIdPerm1->Access, fileDialogIdPerm2->Access, (dynamic_cast<FileDialogPermission^>(fileDialogIdPerm3))->Access );
    }
    else
    {
        Console::WriteLine( "The intersection of {0} and {1} is null.", 
            fileDialogIdPerm1->Access, fileDialogIdPerm2->Access );
    }

    return returnValue;
}

// Intersect creates and returns a new permission that is the 
// intersection of the current
// permission and the permission specified.
private boolean IntersectDemo() 
{
    boolean returnValue = true;
    FileDialogPermissionAccess fileDialog1[] = 
        new FileDialogPermissionAccess[1];
    FileDialogPermissionAccess fileDialog2[] = 
        new FileDialogPermissionAccess[1];
    FileDialogPermission fileDialogIdPerm1[] = 
        new FileDialogPermission[1];
    FileDialogPermission fileDialogIdPerm2[] = 
        new FileDialogPermission[1];
    FileDialogPermission fileDialogIdPerm3 = null;
    FileDialogGenerator fileDialogGen1 =  
        new FileDialogGenerator();
    FileDialogGenerator fileDialogGen2 =  
        new FileDialogGenerator();
    fileDialogGen1.ResetIndex();
    while(fileDialogGen1.CreateFileDialog(
        fileDialogIdPerm1, fileDialog1)) {
        if (fileDialogIdPerm1[0] == null) {
            continue ;
        }
        Console.WriteLine("***************************" 
            + "*******************************\n");
        fileDialogGen2.ResetIndex();
        
        while(fileDialogGen2.CreateFileDialog(
            fileDialogIdPerm2, fileDialog2)) {
            if (fileDialogIdPerm2[0] == null) {
                continue ;
            }
            
            fileDialogIdPerm3 =((FileDialogPermission)
                (fileDialogIdPerm1[0].Intersect
                (fileDialogIdPerm2[0])));
            if (fileDialogIdPerm3  != null) {
                Console.WriteLine(("The intersection of " 
                    + fileDialog1[0] + " and " + fileDialog2[0] 
                    + " = " +((FileDialogPermission)(fileDialogIdPerm3)).
                    get_Access().ToString()));
            }
            else {
                Console.WriteLine(("The intersection of " 
                    + fileDialog1[0] + " and " + fileDialog2[0] 
                    + " is null."));
            }
        }
    }
    return returnValue ;
} //IntersectDemo

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

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