/// <summary>
/// Callback for getting an <see cref="Image"/> asynchronously.
/// We make this static and pass the <see cref="GrhTreeViewNode"/> as the <paramref name="userState"/> so we can
/// just create a single delegate instance and pass that around, greatly reducing garbage and overhead of async operations.
/// </summary>
/// <param name="sender">The <see cref="GrhImageList"/> the callback came from.</param>
/// <param name="gd">The <see cref="StationaryGrhData"/> that the <paramref name="image"/> is for. May be null if the
/// <paramref name="image"/> is equal to <see cref="GrhImageList.ErrorImage"/> or null.</param>
/// <param name="image">The <see cref="Image"/> that was created.</param>
/// <param name="userState">The optional user state object that was passed to the method.</param>
static void GrhImageListAsyncCallback(GrhImageList sender, StationaryGrhData gd, Image image, object userState)
{
var node = (GrhTreeViewNode)userState;
// If the async callback was run on another thread, we will have to use Control.Invoke() to get it to the correct thread.
// Unfortunately, this will result in a bit of overhead and create some garbage due to the parameter list, but
// its the best we can do (as far as I can see) and GrhImageList avoids running a new thread when possible anyways so
// it only really happens while loading.
if (!node.TreeView.InvokeRequired)
{
SetNodeImage(node, image);
}
else
{
node.TreeView.Invoke(_setNodeImage, node, image);
}
}
/// <summary>
/// Initializes the <see cref="GrhImageList"/> class.
/// </summary>
static GrhImageList()
{
// Load the folder images
_openFolder = Resources.folderopen;
_closedFolder = Resources.folder;
// Create the error image
var bmp = new Bitmap(16, 16, PixelFormat.Format32bppArgb);
using (var g = System.Drawing.Graphics.FromImage(bmp))
{
g.Clear(Color.White);
g.DrawLine(Pens.Red, new Point(0, 0), new Point(bmp.Width, bmp.Height));
g.DrawLine(Pens.Red, new Point(bmp.Width, 0), new Point(0, bmp.Height));
}
_errorImage = bmp;
// Create the placeholder image
_placeholder = ImageHelper.CreateSolid(1, 1, Color.White);
// Load the instance
_instance = new GrhImageList();
}
/// <summary>
/// Initializes the <see cref="GrhImageList"/> class.
/// </summary>
static GrhImageList()
{
// Load the folder images
_openFolder = Resources.folderopen;
_closedFolder = Resources.folder;
// Create the error image
var bmp = new Bitmap(16, 16, PixelFormat.Format32bppArgb);
using (var g = System.Drawing.Graphics.FromImage(bmp))
{
g.Clear(Color.White);
g.DrawLine(Pens.Red, new Point(0, 0), new Point(bmp.Width, bmp.Height));
g.DrawLine(Pens.Red, new Point(bmp.Width, 0), new Point(0, bmp.Height));
}
_errorImage = bmp;
// Create the placeholder image
_placeholder = ImageHelper.CreateSolid(1, 1, Color.White);
// Load the instance
_instance = new GrhImageList();
}
/// <summary>
/// Initializes the <see cref="GrhTreeViewNode"/> class.
/// </summary>
static GrhTreeViewNode()
{
_grhImageList = GrhImageList.Instance;
_asyncCallback = GrhImageListAsyncCallback;
_setNodeImage = SetNodeImage;
}
/// <summary>
/// Callback for getting an <see cref="Image"/> asynchronously.
/// We make this static and pass the <see cref="GrhTreeViewNode"/> as the <paramref name="userState"/> so we can
/// just create a single delegate instance and pass that around, greatly reducing garbage and overhead of async operations.
/// </summary>
/// <param name="sender">The <see cref="GrhImageList"/> the callback came from.</param>
/// <param name="gd">The <see cref="StationaryGrhData"/> that the <paramref name="image"/> is for. May be null if the
/// <paramref name="image"/> is equal to <see cref="GrhImageList.ErrorImage"/> or null.</param>
/// <param name="image">The <see cref="Image"/> that was created.</param>
/// <param name="userState">The optional user state object that was passed to the method.</param>
static void GrhImageListAsyncCallback(GrhImageList sender, StationaryGrhData gd, Image image, object userState)
{
var node = (GrhTreeViewNode)userState;
var treeView = node.TreeView;
if (treeView == null)
return;
// If the async callback was run on another thread, we will have to use Control.Invoke() to get it to the correct thread.
// Unfortunately, this will result in a bit of overhead and create some garbage due to the parameter list, but
// its the best we can do (as far as I can see) and GrhImageList avoids running a new thread when possible anyways so
// it only really happens while loading.
if (!treeView.InvokeRequired)
SetNodeImage(node, image);
else
treeView.Invoke(_setNodeImage, node, image);
}
/// <summary>
/// Initializes the <see cref="GrhTreeViewNode"/> class.
/// </summary>
static GrhTreeViewNode()
{
_grhImageList = GrhImageList.Instance;
_asyncCallback = GrhImageListAsyncCallback;
_setNodeImage = SetNodeImage;
}
