IPermission.Intersect(IPermission) 方法

定义

命名空间:

System.Security

程序集:

System.Runtime.dll

创建并返回一个权限，该权限是当前权限与指定权限的交集。

public:
 System::Security::IPermission ^ Intersect(System::Security::IPermission ^ target);

public System.Security.IPermission? Intersect (System.Security.IPermission? target);

abstract member Intersect : System.Security.IPermission -> System.Security.IPermission

Public Function Intersect (target As IPermission) As IPermission

参数

target

IPermission

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

IPermission

表示当前权限和指定权限的交集的一个新权限。 如果交集为空，则此新权限为 null。

例外

ArgumentException

target 参数不为 null，并且是与当前权限不属于同一类的实例。

示例

下面的代码示例演示如何实现 Intersect 方法。 此代码示例是为 IPermission 类提供的一个更大示例的一部分。

    // Return a new object that contains the intersection 
    // of 'this' and 'target'.
public:
    virtual IPermission^ Intersect(IPermission^ target) override
    {
        // If 'target' is null, return null.
        if (target == nullptr)
        {
            return nullptr;
        }

        // Both objects must be the same type.
        SoundPermission^ soundPerm = VerifyTypeMatch(target);

        // If 'this' and 'target' are unrestricted, 
        // return a new unrestricted permission.
        if (specifiedAsUnrestricted && soundPerm->specifiedAsUnrestricted)
        {
            return Clone(true, SoundPermissionState::PlayAnySound);
        }

        // Calculate the intersected permissions. 
        // If there are none, return null.
        SoundPermissionState minimumPermission = (SoundPermissionState)
            Math::Min((int) stateFlags, (int) soundPerm->stateFlags);
        if ((int)minimumPermission == 0)
        {
            return nullptr;
        }

        // Return a new object with the intersected permission value.
        return Clone(false, minimumPermission);
    }

// Return a new object that contains the intersection of 'this' and 'target'.
public override IPermission Intersect(IPermission target)
{
    // If 'target' is null, return null.
    if (target == null) return null;

    // Both objects must be the same type.
    SoundPermission soundPerm = VerifyTypeMatch(target);

    // If 'this' and 'target' are unrestricted, return a new unrestricted permission.
    if (m_specifiedAsUnrestricted && soundPerm.m_specifiedAsUnrestricted)
        return Clone(true, SoundPermissionState.PlayAnySound);

    // Calculate the intersected permissions. If there are none, return null.
    SoundPermissionState val = (SoundPermissionState)
        Math.Min((Int32)m_flags, (Int32)soundPerm.m_flags);
    if (val == 0) return null;

    // Return a new object with the intersected permission value.
    return Clone(false, val);
}

' Return a new object that contains the intersection of 'this' and 'target'.
Public Overrides Function Intersect(ByVal target As IPermission) As IPermission
    ' If 'target' is null, return null.
    If target Is Nothing Then
        Return Nothing
    End If
    ' Both objects must be the same type.
    Dim soundPerm As SoundPermission = VerifyTypeMatch(target)

    ' If 'this' and 'target' are unrestricted, return a new unrestricted permission.
    If m_specifiedAsUnrestricted AndAlso soundPerm.m_specifiedAsUnrestricted Then
        Return Clone(True, SoundPermissionState.PlayAnySound)
    End If
    ' Calculate the intersected permissions. If there are none, return null.
    Dim val As SoundPermissionState = CType(Math.Min(CType(m_flags, Int32), CType(soundPerm.m_flags, Int32)), SoundPermissionState)
    If val = 0 Then
        Return Nothing
    End If
    ' Return a new object with the intersected permission value.
    Return Clone(False, val)

End Function 'Intersect

注解

两个权限的交集是描述它们共同描述的操作集的权限。 只有传递两个原始权限的要求才会通过交集。

对于 方法的所有实现 Intersect ，以下语句必须为 true。 X 和 Y 表示 IPermission 不是 null的对象引用。

• X.相交 (X) 返回等于 X的值。

• X.相交 (Y) 返回与 相同的值 Y。 (X) 相交。

• X.相交 (null) 返回 null。