/// <summary>
/// Browses a single branch of the address space and returns zero or more OPCBROWSEELEMENT
/// structures.
/// It is assumed that the underlying server address space is hierarchical. A flat space will always be
/// presented to the client as not having children. A hierarchical space can be presented to the client as
/// either not having children or having children.
/// A hierarchical presentation of the server address space would behave much like a file system, where
/// the directories are the branches or paths, and the files represent the leaves or items. For example, a
/// server could present a control system by showing all the control networks, then all of the devices on a
/// selected network, and then all of the classes of data within a device, then all of the data items of that
/// class. A further breakdown into vendor specific ‘Units’ and ‘Lines’ might be appropriate for a
/// BATCH system.
/// The browse position is initially set to the ‘root’ of the address space. On subsequent calls, the client
/// may choose to browse from the continuation point.
/// This browse can also be filtered by a vendor specific filter string.
/// </summary>
/// <param name="itemId">
/// The name of the branch in the hierarchy to browse. If the root branch is
/// to be browsed then a NUL string is passed.
/// </param>
/// <param name="filter">
/// An enumeration {All, Branch, Item} specifying which subset of browse
/// elements to return. See the table in the comments section below to
/// determine which combination of bits in
/// in dwBrowseFilter.
/// </param>
/// <param name="elementNameFilter">
/// A wildcard string that conforms to the Visual Basic LIKE operator,
/// which will be used to filter Element names. A NUL String implies no
/// filter.
/// </param>
/// <param name="vendorFilter">
/// A server specific filter string. This is entirely free format and may be
/// entered by the user via an EDIT field. A pointer to a NUL string indicates
/// no filtering.
/// </param>
/// <param name="returnAllProperties">
/// Server must return all properties which are available for each of the
/// returned elements. If true, pdwPropertyIDs is ignored.
/// </param>
/// <param name="returnPropertyValues">Server must return the property values in addition to the property names. </param>
/// <param name="propertyIds">
/// An array of Property IDs to be returned with each element. if
/// bReturnAllProperties is true, pdwPropertyIDs is ignored and all
/// properties are returned.
/// </param>
/// <returns></returns>
public OpcDaBrowseElement[] Browse(string itemId = "", OpcDaBrowseFilter filter = OpcDaBrowseFilter.All,
string elementNameFilter = "",
string vendorFilter = "", bool returnAllProperties = false, bool returnPropertyValues = false,
IList <int> propertyIds = null)
{
IntPtr continuationPoint = IntPtr.Zero;
int dwMaxElementsReturned = OpcConfiguration.BatchSize;
var dwBrowseFilter = (OPCBROWSEFILTER)filter;
string szElementNameFilter = elementNameFilter ?? string.Empty;
string szVendorFilter = vendorFilter ?? string.Empty;
int[] pdwPropertyIDs = propertyIds != null?propertyIds.ToArray() : new int[0];
int dwPropertyCount = propertyIds == null ? 0 : pdwPropertyIDs.Length;
var elements = new List <OpcDaBrowseElement>();
try
{
int pbMoreElements = 0;
do
{
try
{
var browseElements = new IntPtr();
int pdwCount = 0;
DoComCall(ComObject, "IOpcBrowse::Browse", () => ComObject.Browse(itemId, ref continuationPoint, dwMaxElementsReturned, dwBrowseFilter,
szElementNameFilter, szVendorFilter, returnAllProperties, returnPropertyValues,
dwPropertyCount, pdwPropertyIDs, out pbMoreElements, out pdwCount, out browseElements), itemId, dwMaxElementsReturned, dwBrowseFilter,
szElementNameFilter, szVendorFilter, returnAllProperties, returnPropertyValues,
dwPropertyCount, pdwPropertyIDs);
ReadBrowseElementsAndDealocate(ref browseElements, pdwCount, elements);
}
catch (Exception ex)
{
break; // stop browsing.
}
} while ((continuationPoint != IntPtr.Zero && pbMoreElements != 0));
}
finally
{
Marshal.FreeCoTaskMem(continuationPoint);
}
return(elements.ToArray());
}
/// <summary>
/// Browses a single branch of the address space and returns zero or more OPCBROWSEELEMENT
/// structures.
/// It is assumed that the underlying server address space is hierarchical. A flat space will always be
/// presented to the client as not having children. A hierarchical space can be presented to the client as
/// either not having children or having children.
/// A hierarchical presentation of the server address space would behave much like a file system, where
/// the directories are the branches or paths, and the files represent the leaves or items. For example, a
/// server could present a control system by showing all the control networks, then all of the devices on a
/// selected network, and then all of the classes of data within a device, then all of the data items of that
/// class. A further breakdown into vendor specific ‘Units’ and ‘Lines’ might be appropriate for a
/// BATCH system.
/// The browse position is initially set to the ‘root’ of the address space. On subsequent calls, the client
/// may choose to browse from the continuation point.
/// This browse can also be filtered by a vendor specific filter string.
/// </summary>
/// <param name="itemId">
/// The name of the branch in the hierarchy to browse. If the root branch is
/// to be browsed then a NUL string is passed.
/// </param>
/// <param name="filter">
/// An enumeration {All, Branch, Item} specifying which subset of browse
/// elements to return. See the table in the comments section below to
/// determine which combination of bits in
/// in dwBrowseFilter.
/// </param>
/// <param name="elementNameFilter">
/// A wildcard string that conforms to the Visual Basic LIKE operator,
/// which will be used to filter Element names. A NUL String implies no
/// filter.
/// </param>
/// <param name="vendorFilter">
/// A server specific filter string. This is entirely free format and may be
/// entered by the user via an EDIT field. A pointer to a NUL string indicates
/// no filtering.
/// </param>
/// <param name="returnAllProperties">
/// Server must return all properties which are available for each of the
/// returned elements. If true, pdwPropertyIDs is ignored.
/// </param>
/// <param name="returnPropertyValues">Server must return the property values in addition to the property names. </param>
/// <param name="propertyIds">
/// An array of Property IDs to be returned with each element. if
/// bReturnAllProperties is true, pdwPropertyIDs is ignored and all
/// properties are returned.
/// </param>
/// <returns></returns>
public OpcDaBrowseElement[] Browse(string itemId = "", OpcDaBrowseFilter filter = OpcDaBrowseFilter.All,
string elementNameFilter = "",
string vendorFilter = "", bool returnAllProperties = false, bool returnPropertyValues = false,
IList<int> propertyIds = null)
{
IntPtr continuationPoint = IntPtr.Zero;
int dwMaxElementsReturned = OpcConfiguration.BatchSize;
var dwBrowseFilter = (OPCBROWSEFILTER) filter;
string szElementNameFilter = elementNameFilter ?? string.Empty;
string szVendorFilter = vendorFilter ?? string.Empty;
int[] pdwPropertyIDs = propertyIds != null ? propertyIds.ToArray() : new int[0];
int dwPropertyCount = propertyIds == null ? 0 : pdwPropertyIDs.Length;
var elements = new List<OpcDaBrowseElement>();
try
{
int pbMoreElements = 0;
do
{
try
{
var browseElements = new IntPtr();
int pdwCount = 0;
DoComCall(ComObject,"IOpcBrowse::Browse", () => ComObject.Browse(itemId, ref continuationPoint, dwMaxElementsReturned, dwBrowseFilter,
szElementNameFilter, szVendorFilter, returnAllProperties, returnPropertyValues,
dwPropertyCount, pdwPropertyIDs, out pbMoreElements, out pdwCount, out browseElements), itemId, dwMaxElementsReturned, dwBrowseFilter,
szElementNameFilter, szVendorFilter, returnAllProperties, returnPropertyValues,
dwPropertyCount, pdwPropertyIDs);
ReadBrowseElementsAndDealocate(ref browseElements, pdwCount, elements);
}
catch (Exception ex)
{
break; // stop browsing.
}
} while ((continuationPoint != IntPtr.Zero && pbMoreElements != 0));
}
finally
{
Marshal.FreeCoTaskMem(continuationPoint);
}
return elements.ToArray();
}
