Class DistanceCounterCollection

A collection of entities for which distances need to be counted. The collection provides methods for mapping from a distance position to an entity and vice versa.

For example, in a scrollable grid control you have rows with different heights. Use this collection to determine the total height for all rows in the grid, quickly detemine the row index for a given point and also quickly determine the point at which a row is displayed. This also allows a mapping between the scrollbars value and the rows or columns associated with that value.

Inheritance

System.Object

DistanceCounterCollection

Implements

IDistanceCounterCollection

Namespace: Syncfusion.Windows.Controls.Scroll

Assembly: Syncfusion.GridCommon.WPF.dll

Syntax

public class DistanceCounterCollection : Object, IDistanceCounterCollection

Remarks

DistanceCounterCollection uses a high-water mark technique for allocating objects up to the modified entry with the highest index. When you modify the size of an entry the collection ensures that that objects are allocated for all entries up to the given index. Entries that are after the modified entry are assumed to have the DefaultSize and will not be allocated.

The best-case scenario is when all lines have the same DefaultSize. In such case the internal collection remains completely empty and will not cause any overhead. This makes DistanceCounterCollection also an attractive solution for the scenario where all entries have the same size (e.g. a databound grid where all rows have same height).

Constructors

DistanceCounterCollection()

Constructs the class and initializes the internal tree.

Declaration

public DistanceCounterCollection()

Properties

Count

The raw number of entities (lines, rows or columns).

Declaration

public int Count { get; set; }

Property Value

Type
System.Int32

DefaultDistance

The default distance (row height or column width) an entity spans

Declaration

public double DefaultDistance { get; set; }

Property Value

Type
System.Double

Item[Int32]

Gets or sets the distance for an entity.

Declaration

public double this[int index] { get; set; }

Parameters

Type	Name	Description
System.Int32	index	The index for the entity

Property Value

Type
System.Double

TotalDistance

The total distance all entities span (e.g. total height of all rows in grid)

Declaration

public double TotalDistance { get; }

Property Value

Type
System.Double

Methods

Clear()

Clears this instance.

Declaration

public void Clear()

ConnectWithParent(ITreeTableCounterSource)

Connects a nested distance collection with a parent.

Declaration

public void ConnectWithParent(ITreeTableCounterSource nestedTreeTableVisibleCounterSource)

Parameters

Type	Name	Description
ITreeTableCounterSource	nestedTreeTableVisibleCounterSource	The nested tree table visible counter source.

GetAlignedScrollValue(Double)

Gets the aligned scroll value which is the starting point of the entity found at the given distance position.

Declaration

public double GetAlignedScrollValue(double point)

Parameters

Type	Name	Description
System.Double	point	The point.

Returns

Type	Description
System.Double	The starting point of the entity.

GetCumulatedDistanceAt(Int32)

Gets the cumulated count of previous distances for the entity at the specifiec index. (e.g. return pixel position for a row index).

Declaration

public double GetCumulatedDistanceAt(int index)

Parameters

Type	Name	Description
System.Int32	index	The entity index.

Returns

Type	Description
System.Double	The cumulated count of previous distances for the entity at the specifiec index.

GetNestedDistances(Int32)

Gets the nested entities at a given index. If the index does not hold a mested distances collection the method returns null.

Declaration

public IDistanceCounterCollection GetNestedDistances(int index)

Parameters

Type	Name	Description
System.Int32	index	The index.

Returns

Type	Description
IDistanceCounterCollection	The nested collection or null.

GetNextScrollValue(Double)

Gets the distance position of the next entity after a given point.

Declaration

public double GetNextScrollValue(double point)

Parameters

Type	Name	Description
System.Double	point	The point.

Returns

Type	Description
System.Double	The distance position.

GetNextVisibleIndex(Int32)

Skip subsequent entities for which the distance is 0.0 and return the next entity.

Declaration

public int GetNextVisibleIndex(int index)

Parameters

Type	Name	Description
System.Int32	index

Returns

Type
System.Int32

GetPreviousScrollValue(Double)

Gets the distance position of the entity preceeding a given point. If the point is in between entities the starting point of the matching entity is returned.

Declaration

public double GetPreviousScrollValue(double point)

Parameters

Type	Name	Description
System.Double	point	The point.

Returns

Type	Description
System.Double	The distance position.

GetPreviousVisibleIndex(Int32)

Skip previous entities for which the distance is 0.0 and return the next entity.

Declaration

public int GetPreviousVisibleIndex(int index)

Parameters

Type	Name	Description
System.Int32	index

Returns

Type
System.Int32

IndexOfCumulatedDistance(Double)

Gets the index of an entity in this collection for which the cumulated count of previous distances is greater or equal the specified cumulatedDistance. (e.g. return row index for pixel position).

Declaration

public int IndexOfCumulatedDistance(double cumulatedDistance)

Parameters

Type	Name	Description
System.Double	cumulatedDistance	The cumulated count of previous distances.

Returns

Type	Description
System.Int32	The entity index.

Insert(Int32, Int32)

Insert entities in the collection.

Declaration

public void Insert(int insertAt, int count)

Parameters

Type	Name	Description
System.Int32	insertAt	Insert position.
System.Int32	count	The number of entities to be inserted.

Remove(Int32, Int32)

Removes enities from the collection.

Declaration

public void Remove(int removeAt, int count)

Parameters

Type	Name	Description
System.Int32	removeAt	Index of the first entity to be removed.
System.Int32	count	The number of entities to be removed.

ResetRange(Int32, Int32)

Resets the range by restoring the default distance for all entries in the specified range.

Declaration

public void ResetRange(int from, int to)

Parameters

Type	Name	Description
System.Int32	from	From.
System.Int32	to	To.

SetNestedDistances(Int32, IDistanceCounterCollection)

Assigns a collection with nested entities to an item.

Declaration

public void SetNestedDistances(int index, IDistanceCounterCollection nestedCollection)

Parameters

Type	Name	Description
System.Int32	index	The index.
IDistanceCounterCollection	nestedCollection	The nested collection.

SetRange(Int32, Int32, Double)

Hides a specified range of entities (lines, rows or colums)

Declaration

public void SetRange(int from, int to, double distance)

Parameters

Type	Name	Description
System.Int32	from	The index for the first entity>
System.Int32	to	The raw index for the last entity
System.Double	distance	The distance.

Test()

Tests this instance.

Declaration

public static void Test()

Implements

IDistanceCounterCollection