/// <summary>
/// Recalculates the control layout.
/// <param name="forceUpdate">true to force an update; otherwise false.</param>
/// </summary>
public void Update(bool forceUpdate)
{
if (mImageListView.ClientRectangle.Width == 0 || mImageListView.ClientRectangle.Height == 0)
return;
// If only item order is changed, just update visible items.
if (!forceUpdate && !UpdateRequired && mImageListView.Items.collectionModified)
{
UpdateGroups();
UpdateVisibleItems();
return;
}
if (!forceUpdate && !UpdateRequired)
return;
// Get the item size from the renderer
mItemSize = mImageListView.mRenderer.MeasureItem(mImageListView.View);
cachedItemMargin = mImageListView.mRenderer.MeasureItemMargin(mImageListView.View);
mItemSizeWithMargin = mItemSize + cachedItemMargin;
// Cache current properties to determine if we will need an update later
bool viewChanged = (cachedView != mImageListView.View);
cachedView = mImageListView.View;
cachedViewOffset = mImageListView.ViewOffset;
cachedSize = mImageListView.ClientSize;
cachedItemCount = mImageListView.Items.Count;
cachedIntegralScroll = mImageListView.IntegralScroll;
cachedItemSize = mItemSize;
cachedGroupHeaderHeight = mImageListView.mRenderer.MeasureGroupHeaderHeight();
cachedColumnHeaderHeight = mImageListView.mRenderer.MeasureColumnHeaderHeight();
cachedPaneWidth = mImageListView.PaneWidth;
cachedScrollBars = mImageListView.ScrollBars;
mImageListView.Items.collectionModified = false;
mImageListView.groups.collectionModified = false;
// Calculate item area bounds
if (!UpdateItemArea())
return;
// Let the calculated bounds modified by the renderer
LayoutEventArgs eLayout = new LayoutEventArgs(mItemAreaBounds);
mImageListView.mRenderer.OnLayout(eLayout);
mItemAreaBounds = eLayout.ItemAreaBounds;
if (mItemAreaBounds.Width <= 0 || mItemAreaBounds.Height <= 0)
return;
// Calculate the number of rows and columns
CalculateGrid();
// Update groups
UpdateGroups();
// Check if we need the scroll bars.
// Recalculate the layout if scroll bar visibility changes.
if (CheckScrollBars())
{
Update(true);
return;
}
// Update scroll range
UpdateScrollBars();
// Cache visible items
UpdateVisibleItems();
// Recalculate the layout if view mode was changed
if (viewChanged)
Update();
}
/// <summary>
/// Recalculates the control layout.
/// </summary>
public void Update(bool forceUpdate)
{
if (mImageListView.ClientRectangle.Width == 0 || mImageListView.ClientRectangle.Height == 0) return;
if (!forceUpdate && !UpdateRequired) return;
// Cache current properties to determine if we will need an update later
cachedView = mImageListView.View;
cachedViewOffset = mImageListView.ViewOffset;
cachedSize = mImageListView.ClientSize;
cachedItemCount = mImageListView.Items.Count;
cachedItemSize = mImageListView.mRenderer.MeasureItem(mImageListView.View);
cachedHeaderHeight = mImageListView.mRenderer.MeasureColumnHeaderHeight();
cachedItemMargin = mImageListView.mRenderer.MeasureItemMargin(mImageListView.View);
cachedPaneWidth = mImageListView.PaneWidth;
cachedScrollBars = mImageListView.ScrollBars;
cachedVisibleItems.Clear();
// Calculate drawing area
mClientArea = mImageListView.ClientRectangle;
mItemAreaBounds = mImageListView.ClientRectangle;
// Item size
mItemSize = cachedItemSize;
mItemSizeWithMargin = mItemSize + cachedItemMargin;
// Allocate space for scrollbars
if (mImageListView.hScrollBar.Visible)
{
mClientArea.Height -= mImageListView.hScrollBar.Height;
mItemAreaBounds.Height -= mImageListView.hScrollBar.Height;
}
if (mImageListView.vScrollBar.Visible)
{
mClientArea.Width -= mImageListView.vScrollBar.Width;
mItemAreaBounds.Width -= mImageListView.vScrollBar.Width;
}
// Allocate space for column headers
if (mImageListView.View == View.Details)
{
int headerHeight = cachedHeaderHeight;
// Location of the column headers
mColumnHeaderBounds.X = mClientArea.Left - mImageListView.ViewOffset.X;
mColumnHeaderBounds.Y = mClientArea.Top;
mColumnHeaderBounds.Height = headerHeight;
mColumnHeaderBounds.Width = mClientArea.Width + mImageListView.ViewOffset.X;
mItemAreaBounds.Y += headerHeight;
mItemAreaBounds.Height -= headerHeight;
}
else
{
mColumnHeaderBounds = Rectangle.Empty;
}
// Modify item area for the gallery view mode
if (mImageListView.View == View.Gallery)
{
mItemAreaBounds.Height = mItemSizeWithMargin.Height;
mItemAreaBounds.Y = mClientArea.Bottom - mItemSizeWithMargin.Height;
}
// Modify item area for the pane view mode
if (mImageListView.View == View.Pane)
{
mItemAreaBounds.Width -= cachedPaneWidth;
mItemAreaBounds.X += cachedPaneWidth;
}
if (mItemAreaBounds.Width < 1 || mItemAreaBounds.Height < 1) return;
// Let the calculated bounds modified by the renderer
LayoutEventArgs eLayout = new LayoutEventArgs(mItemAreaBounds);
mImageListView.mRenderer.OnLayout(eLayout);
mItemAreaBounds = eLayout.ItemAreaBounds;
// Maximum number of rows and columns that can be fully displayed
mCols = (int)System.Math.Floor((float)mItemAreaBounds.Width / (float)mItemSizeWithMargin.Width);
mRows = (int)System.Math.Floor((float)mItemAreaBounds.Height / (float)mItemSizeWithMargin.Height);
if (mImageListView.View == View.Details) mCols = 1;
if (mImageListView.View == View.Gallery) mRows = 1;
if (mCols < 1) mCols = 1;
if (mRows < 1) mRows = 1;
// Check if we need the horizontal scroll bar
bool hScrollRequired = false;
if (mImageListView.ScrollBars)
{
if (mImageListView.View == View.Gallery)
hScrollRequired = (mImageListView.Items.Count > 0) && (mCols * mRows < mImageListView.Items.Count);
else
hScrollRequired = (mImageListView.Items.Count > 0) && (mItemAreaBounds.Width < mCols * mItemSizeWithMargin.Width);
}
if (hScrollRequired != hScrollVisible)
{
hScrollVisible = hScrollRequired;
mImageListView.hScrollBar.Visible = hScrollRequired;
Update(true);
return;
}
// Check if we need the vertical scroll bar
bool vScrollRequired = false;
if (mImageListView.ScrollBars)
{
if (mImageListView.View == View.Gallery)
vScrollRequired = (mImageListView.Items.Count > 0) && (mItemAreaBounds.Height < mRows * mItemSizeWithMargin.Height);
else
vScrollRequired = (mImageListView.Items.Count > 0) && (mCols * mRows < mImageListView.Items.Count);
}
if (vScrollRequired != vScrollVisible)
{
vScrollVisible = vScrollRequired;
mImageListView.vScrollBar.Visible = vScrollRequired;
Update(true);
return;
}
// Horizontal scroll range
if (mImageListView.View == View.Gallery)
{
mImageListView.hScrollBar.SmallChange = mItemSizeWithMargin.Width;
mImageListView.hScrollBar.LargeChange = mItemSizeWithMargin.Width * (mItemAreaBounds.Width / mItemSizeWithMargin.Width);
mImageListView.hScrollBar.Minimum = 0;
mImageListView.hScrollBar.Maximum = Math.Max(0, (int)System.Math.Ceiling((float)mImageListView.Items.Count / (float)mRows) * mItemSizeWithMargin.Width - 1);
}
else
{
mImageListView.hScrollBar.SmallChange = 1;
mImageListView.hScrollBar.LargeChange = mItemAreaBounds.Width;
mImageListView.hScrollBar.Minimum = 0;
mImageListView.hScrollBar.Maximum = mCols * mItemSizeWithMargin.Width;
}
if (mImageListView.ViewOffset.X > mImageListView.hScrollBar.Maximum - mImageListView.hScrollBar.LargeChange + 1)
{
mImageListView.hScrollBar.Value = mImageListView.hScrollBar.Maximum - mImageListView.hScrollBar.LargeChange + 1;
mImageListView.ViewOffset = new Point(mImageListView.hScrollBar.Value, mImageListView.ViewOffset.Y);
}
// Vertical scroll range
if (mImageListView.View == View.Gallery)
{
mImageListView.vScrollBar.SmallChange = 1;
mImageListView.vScrollBar.LargeChange = mItemAreaBounds.Height;
mImageListView.vScrollBar.Minimum = 0;
mImageListView.vScrollBar.Maximum = mRows * mItemSizeWithMargin.Height;
}
else
{
mImageListView.vScrollBar.SmallChange = mItemSizeWithMargin.Height;
mImageListView.vScrollBar.LargeChange = mItemSizeWithMargin.Height * (mItemAreaBounds.Height / mItemSizeWithMargin.Height);
mImageListView.vScrollBar.Minimum = 0;
mImageListView.vScrollBar.Maximum = Math.Max(0, (int)System.Math.Ceiling((float)mImageListView.Items.Count / (float)mCols) * mItemSizeWithMargin.Height - 1);
}
if (mImageListView.ViewOffset.Y > mImageListView.vScrollBar.Maximum - mImageListView.vScrollBar.LargeChange + 1)
{
mImageListView.vScrollBar.Value = mImageListView.vScrollBar.Maximum - mImageListView.vScrollBar.LargeChange + 1;
mImageListView.ViewOffset = new Point(mImageListView.ViewOffset.X, mImageListView.vScrollBar.Value);
}
// Zero out the scrollbars if we don't have any items
if (mImageListView.Items.Count == 0)
{
mImageListView.hScrollBar.Minimum = 0;
mImageListView.hScrollBar.Maximum = 0;
mImageListView.hScrollBar.Value = 0;
mImageListView.vScrollBar.Minimum = 0;
mImageListView.vScrollBar.Maximum = 0;
mImageListView.vScrollBar.Value = 0;
mImageListView.ViewOffset = new Point(0, 0);
}
// Horizontal scrollbar position
mImageListView.hScrollBar.Left = 0;
mImageListView.hScrollBar.Top = mImageListView.ClientRectangle.Bottom - mImageListView.hScrollBar.Height;
mImageListView.hScrollBar.Width = mImageListView.ClientRectangle.Width - (mImageListView.vScrollBar.Visible ? mImageListView.vScrollBar.Width : 0);
// Vertical scrollbar position
mImageListView.vScrollBar.Left = mImageListView.ClientRectangle.Right - mImageListView.vScrollBar.Width;
mImageListView.vScrollBar.Top = 0;
mImageListView.vScrollBar.Height = mImageListView.ClientRectangle.Height - (mImageListView.hScrollBar.Visible ? mImageListView.hScrollBar.Height : 0);
// Find the first and last partially visible items
if (mImageListView.View == View.Gallery)
{
mFirstPartiallyVisible = (int)System.Math.Floor((float)mImageListView.ViewOffset.X / (float)mItemSizeWithMargin.Width) * mRows;
mLastPartiallyVisible = (int)System.Math.Ceiling((float)(mImageListView.ViewOffset.X + mItemAreaBounds.Width) / (float)mItemSizeWithMargin.Width) * mRows - 1;
}
else
{
mFirstPartiallyVisible = (int)System.Math.Floor((float)mImageListView.ViewOffset.Y / (float)mItemSizeWithMargin.Height) * mCols;
mLastPartiallyVisible = (int)System.Math.Ceiling((float)(mImageListView.ViewOffset.Y + mItemAreaBounds.Height) / (float)mItemSizeWithMargin.Height) * mCols - 1;
}
if (mFirstPartiallyVisible < 0) mFirstPartiallyVisible = 0;
if (mFirstPartiallyVisible > mImageListView.Items.Count - 1) mFirstPartiallyVisible = mImageListView.Items.Count - 1;
if (mLastPartiallyVisible < 0) mLastPartiallyVisible = 0;
if (mLastPartiallyVisible > mImageListView.Items.Count - 1) mLastPartiallyVisible = mImageListView.Items.Count - 1;
// Find the first and last visible items
if (mImageListView.View == View.Gallery)
{
mFirstVisible = (int)System.Math.Ceiling((float)mImageListView.ViewOffset.X / (float)mItemSizeWithMargin.Width) * mRows;
mLastVisible = (int)System.Math.Floor((float)(mImageListView.ViewOffset.X + mItemAreaBounds.Width) / (float)mItemSizeWithMargin.Width) * mRows - 1;
}
else
{
mFirstVisible = (int)System.Math.Ceiling((float)mImageListView.ViewOffset.Y / (float)mItemSizeWithMargin.Height) * mCols;
mLastVisible = (int)System.Math.Floor((float)(mImageListView.ViewOffset.Y + mItemAreaBounds.Height) / (float)mItemSizeWithMargin.Height) * mCols - 1;
}
if (mFirstVisible < 0) mFirstVisible = 0;
if (mFirstVisible > mImageListView.Items.Count - 1) mFirstVisible = mImageListView.Items.Count - 1;
if (mLastVisible < 0) mLastVisible = 0;
if (mLastVisible > mImageListView.Items.Count - 1) mLastVisible = mImageListView.Items.Count - 1;
// Cache visible items
if (mFirstPartiallyVisible >= 0 &&
mLastPartiallyVisible >= 0 &&
mFirstPartiallyVisible <= mImageListView.Items.Count - 1 &&
mLastPartiallyVisible <= mImageListView.Items.Count - 1)
{
for (int i = mFirstPartiallyVisible; i <= mLastPartiallyVisible; i++)
cachedVisibleItems.Add(mImageListView.Items[i].Guid, false);
}
}
