IPermission.Intersect Method (IPermission)

 

Creates and returns a permission that is the intersection of the current permission and the specified permission.

Namespace:   System.Security
Assembly:  mscorlib (in mscorlib.dll)

IPermission Intersect(
	IPermission target
)

Parameters

target
Type: System.Security.IPermission

A permission to intersect with the current permission. It must be of the same type as the current permission.

Return Value

Type: System.Security.IPermission

A new permission that represents the intersection of the current permission and the specified permission. This new permission is null if the intersection is empty.

Exception Condition
ArgumentException

The target parameter is not null and is not an instance of the same class as the current permission.

The intersection of two permissions is a permission that describes the set of operations they both describe in common. Only a demand that passes both original permissions will pass the intersection.

The following statements are required to be true for all implementations of the Intersect method. X and Y represent IPermission object references that are not null.

  • X.Intersect(X) returns a value equal to X.

  • X.Intersect(Y) returns the same value as Y.Intersect(X).

  • X.Intersect(null) returns null.

The following code example demonstrates implementing the Intersect method. This code example is part of a larger example provided for the IPermission class.

// 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);
}

.NET Framework
Available since 1.1
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