The point binder (represented by a PointBinder component) provides live binding to generic data points (see further below). It supports just one type of binding – a PointBinding; however, the point binding type is so generic that it can easily describe OPC-DA “Classic” items, properties, OPC-UA nodes (attributes), or just about any other point-based data source.
The point binder makes use of the Connectivity Model, described in a separate section. Please refer to the relevant parts of documentation for information about the Connectivity Model.
Connectivities provide access to data sources.
The developer will usually start the live binding by placing one of these connectivity components from the Visual Studio Toolbox onto the component tray (in Windows Forms, by dragging from the Toolbox to the design surface of the form; in WPF, using the context menu command, and the Component Tray Editor dialog then).
Notice that after placing any of the connectivity components onto an empty component tray, three components will appear below on the component tray: Besides the one for the connectivity itself, there will be one for the PointBinder, and one for BindingExtender.
If, after placing a connectivity component to a component tray, the PointBinder and the BindingExtender components are not placed onto the component tray automatically, make sure that the target framework of the project is set to “.NET Framework 4.7.2” or later.
Points in Connectivity Model identify the pieces of data the Live Binding works with.
Point Editor is the dialog used to select, view or modify points.
Parameters determine how the data will be accessed.
The Arguments and Results are the actual data the binding operation transfers, i.e. the “what”.
The PointBinding has an UpdateOutputOnFailure property (defaults to ‘false’). Normally, when an operation (such as OPC read) fails, and you are binding to an operation output, nothing happens - the binding output is not updated. For example, a text bound to an OPC data value continues to display the last known value. When the UpdateOutputOnFailure property is set to ‘true’, the binding output will always be updated. In our example, the text box will be cleared in case of operation failure.