/// <summary>
/// Change the width of the given column. This is a helper function to
/// facilitate the final step in updating the header. SetItemWidth does
/// not update the data in the tree control's VirtualTreeColumnHeader
/// structures.
/// </summary>
/// <param name="index">The display column</param>
/// <param name="itemWidth">The new width for the column</param>
public void SetItemWidth(int index, int itemWidth)
{
// The header items can get out of sync here with drag/drop reordering. The
// index requested here will always be the displayed order, not the true index,
// so we need to switch to the true index before moving on.
index = OrderToIndex(index);
var item = new NativeMethods.HDITEM();
item.cxy = itemWidth;
item.mask = NativeMethods.HDITEM.Mask.HDI_WIDTH;
NativeMethods.SendMessage(Handle, NativeMethods.HDM_SETITEMW, index, ref item);
}
/// <summary>
/// Add an item to the control. Always adds in the last position.
/// </summary>
/// <param name="columnHeader">The header information</param>
/// <param name="itemWidth"></param>
public void AddItem(VirtualTreeColumnHeader columnHeader, int itemWidth)
{
var item = new NativeMethods.HDITEM();
item.cxy = itemWidth;
item.mask = NativeMethods.HDITEM.Mask.HDI_WIDTH;
SetAppearanceFields(ref columnHeader, ref item);
NativeMethods.SendMessage(Handle, NativeMethods.HDM_INSERTITEMW, int.MaxValue, ref item);
}
/// <summary>
/// Update the appearance fields (string, glyph, and style) to the new header settings. This
/// cannot be used to update the width or position of the header.
/// </summary>
/// <param name="columnHeader">The header with the current settings</param>
/// <param name="displayColumn">The display column to update</param>
public void UpdateItemAppearance(VirtualTreeColumnHeader columnHeader, int displayColumn)
{
if (IsHandleCreated)
{
var item = new NativeMethods.HDITEM();
SetAppearanceFields(ref columnHeader, ref item);
if (item.mask != 0)
{
NativeMethods.SendMessage(Handle, NativeMethods.HDM_SETITEMW, OrderToIndex(displayColumn), ref item);
}
}
}
/// <summary>
/// Get the current display column for a header index, such as the header
/// index sent with the NMHEADER structure to HDN_* notification messages.
/// </summary>
/// <param name="index">The header index</param>
/// <returns>The column the header is currently displayed at.</returns>
protected int IndexToOrder(int index)
{
if (IsHandleCreated)
{
var item = new NativeMethods.HDITEM();
item.iOrder = index;
item.mask = NativeMethods.HDITEM.Mask.HDI_ORDER;
NativeMethods.SendMessage(Handle, NativeMethods.HDM_GETITEMW, index, ref item);
return item.iOrder;
}
return index;
}
