- None

- None

Specifies the lower and upper limits of an interval, each of which may be infinite or a specific value.

When a condition tree expresses that the value of a property must fall in a certain range, the property can be expressed as a leaf node. The node must be a PROPVARIANT containing a **vt** value type tag of VT_UNKNOWN and an IUnknown* **punkVal** that is a pointer to an object that implements IInterval.

**Syntax**

**Parameters**

pilkLower- [out] Receives a pointer to a value from the INTERVAL_LIMIT_KIND enumeration that indicates whether the lower bound of the interval is inclusive, exclusive, or infinite.
ppropvarLower- [out] Receives a pointer to the value for the lower limit of the interval. If the
pilkLowerparameter is set toILK_NEGATIVE_INFINITYorILK_POSITIVE_INFINITY, this value is set toVT_EMPTY.pilkUpper- [out] Receives a pointer to a value from the
INTERVAL_LIMIT_KINDenumeration that indicates whether the upper bound of the interval is inclusive, exclusive, or infinite.ppropvarUpper- [out] Receives a pointer to the value for the upper limit of the interval. If the
pilkUpperparameter is set toILK_NEGATIVE_INFINITYorILK_POSITIVE_INFINITY, this value will be set toVT_EMPTY.

**Return Value**

Returns S_OK if successful, or an error value otherwise.

**Remarks**

This method retrieves interval limits in two INTERVAL_LIMIT_KIND—PROPVARIANT pairs. The first pair specifies the lower limit of the interval, and the second pari specifies the upper limit of the interval.

The lower limit must be less than the upper limit or the interval will be empty. The only exception is when the lower and upper limits are equal and both are set to

ILK_EXPLICIT_INCLUDED. In this case the range is the single value to which both limits are set. The following table illustrates how the pairs work to define intervals.

pilkLower ppropvarLower pilkLower ppropvarLower Description ILK_EXPLICIT_INCLUDED 3 ILK_EXPLICIT_INCLUDED 3 The lowest value in the range is 3 because the 3 is explicitly included in the range.

The highest value in the range is also 3 (explicitly included), and the interval consists of only the number 3.ILK_EXPLICIT_INCLUDED 3 ILK_EXPLICIT_EXCLUDED 3 The lowest value in the range is 3 (explicitly included), but the upper limit is also 3 and is explicitly excluded. Therefore, the interval being described is an empty interval. ILK_EXPLICIT_INCLUDED 3 ILK_EXPLICIT_EXCLUDED 6 The integer interval begins at and includes 3, and ends at but does not include 6. ILK_NEGATIVE_INFINITY VT_EMPTY ILK_POSITIVE_INFINITY VT_EMPTY All integers are included in the interval.