/// <summary>
/// Browses for children of the element at the current node.
/// </summary>
private void Browse(TreeNode node)
{
try
{
// get the server for the current node.
TsCDaServer server = FindServer(node);
// get the current element to use for a browse.
TsCDaBrowseElement parent = null;
OpcItem itemID = null;
if (node.Tag != null && node.Tag.GetType() == typeof(TsCDaBrowseElement))
{
parent = (TsCDaBrowseElement)node.Tag;
itemID = new OpcItem(parent.ItemPath, parent.ItemName);
}
// clear the node children.
node.Nodes.Clear();
// add properties
if (parent != null && parent.Properties != null)
{
foreach (TsCDaItemProperty property in parent.Properties)
{
AddItemProperty(node, property);
}
}
// begin a browse.
OpcClientSdk.Da.TsCDaBrowsePosition position = null;
TsCDaBrowseElement[] elements = server.Browse(itemID, m_filters, out position);
// add children.
if (elements != null)
{
foreach (TsCDaBrowseElement element in elements)
{
AddBrowseElement(node, element);
}
node.Expand();
}
// loop until all elements have been fetched.
while (position != null)
{
DialogResult result = MessageBox.Show(
"More items meeting search criteria exist. Continue browse?",
"Browse Items",
MessageBoxButtons.YesNo);
if (result == DialogResult.No)
{
break;
}
// fetch next batch of elements,.
elements = server.BrowseNext(ref position);
// add children.
if (elements != null)
{
foreach (TsCDaBrowseElement element in elements)
{
AddBrowseElement(node, element);
}
node.Expand();
}
}
// send notification that property list changed.
if (ElementSelected != null)
{
if (node.Tag.GetType() == typeof(TsCDaBrowseElement))
{
ElementSelected((TsCDaBrowseElement)node.Tag);
}
else
{
ElementSelected(null);
}
}
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}