OPC Data Client includes several controls dedicated to displaying and/or editing values and objects in OPC UA PubSub. They are displayed in this chapter. Note that dedicated controls are only made available for objects where the control provides additional configuration and programmatic features for the developer. For many other objects do not require that, you will use the AutomaticValueControl Class and OPC UA PubSub Control Pages to place the control for a specific object on your form.

All controls described in this section have their corresponding items (icons) in Visual Studio Toolbox. You can therefore drag-and-drop them from the Toolbox to the designer surface of your form.

UAVersionTimeControl

The UAVersionTimeControl Class allows displaying and editing of OPC UA version times, which are dates/times expressed as integers according to specific rules. The OPC UA version time is used e.g. in OPC UA configuration version (UAConfigurationVersion Class), which is a structure that is used to describe version of configuration changes in the information published for an OPC UA PubSub dataset.

Following features of the control are available to you as a developer:

• You can use the Value Property to set the new version time to the control, or retrieve the version time from the control.

An example of the control in action is shown below.

 

The checkbox at the left allows the user to select whether the version is specified or not (an unspecified version time is represented by a zero value). The version time can be displayed or entered in local or UTC time, and the control provides a button that allows the user to select between them.

Sometimes, the version time is treated not as a "meaningful" date and time, but simply as a sequential numerical value. The control has a button that allows to switch the date/time display into a numeric display. When done so, the user can further select whether the value will be represented in decimal or hexadecimal.

UAFieldDataDictionaryControl

The UAFieldDataDictionaryControl displays contents of UAStringDataSetFieldDataDictionary, i.e. a dictionary of OPC UA dataset field data objects, keyed by the field name. This is the actual "data" of OPC UA PubSet dataset. Main part of the control is a list view, where each row represents a field in the dataset. The list view has columns for field names, values, timestamps, and status code associated with the field data. An example of the control in action is shown below.

 

This control is always read-only, i.e. the interactive user cannot modify the data (although he/she can influence how the data is displayed).

Following features of the control are available to you as a developer:

• You can set the new field data dictionary to the Value Property; this will cause the control to display the new data, attempting to prevent flicker as much as possible.
• You can call the RefreshItems Method, if any value in the field data dictionary has changed and you want the control to reflect that change visually.
• By changing the value in the FieldDataColumns Property, you can specify which columns will be displayed in the control.
• Using the PreciseTimeFormat Property, you can choose whether times will be shown in precise format (with fractions of a second).

The interactive user of the control can:

• Use standard features of the list view, such as scroll the dataset field rows, arrange columns order and column sizes, or hover over any incomplete text to display the full text in a tooltip.
• Select which columns are displayed, using the "Columns" drop-down menu at the bottom of the control.
• Choose between General and Precise time formats, using the "Time format:" drop-down menu at the bottom of the control.
• Choose between UTC and Local display of the timestamps, using the "Timestamps:" drop-down menu at the bottom of the control.

The control shows statistics of the fields it displays (sorted by their Good/Uncertain/Bad status) at the bottom. It also colorizes the values and the statistics, using orange color for warnings (Uncertain status) and red color for errors (Bad status).

UADataSetHeaderControl 

The UADataSetHeaderControl Class displays information from the UADataSetHeader Class (header information of an OPC UA PubSub message). An example of the control in action is shown below.

 

This control is always read-only, i.e. the interactive user cannot modify the data.

Following features of the control are available to you as a developer:

• You can set the dataset header value to the Value Property; this will cause the control to display the new data.
• Using the LocalTimestamps Property, you can choose whether timestamps will be primarily shown in local time (as opposed to UTC).
• Using the PreciseTimeFormat Property, you can choose whether times will be shown in precise format (with fractions of a second).

The interactive user of the control can display supplementary information to the displayed fields by hovering over them. For example, hovering over the Publisher Id, Writer group Id or Dataset writer Id shows their values in both decimal and hexadecimal formats. Hovering over timestamps (in configuration version) shows the times in both local and UTC formats, and also shows the numerical value of the configuration version. 

UADataSetDataControl

The UADataSetDataControl Class displays information from the UADataSetData Class (the OPC UA PubSub dataset, consisting of the dataset header, and the dataset fields). The control combines together the UADataSetHeaderControl Class and the UAFieldDataDictionaryControl Class. An example of the control in action is shown below.

 

This control is always read-only, i.e. the interactive user cannot modify the data (although he/she can influence how the data is displayed).

Following features of the control are available to you as a developer:

• You can set the dataset data value to the Value Property; this will cause the control to display the new data.
• Using dedicated properties, you can choose which columns of the dataset fields will be displayed. These properties are: ShowServerTimestampColumn Property, ShowSourceTimestampColumn Property, ShowStatusCodeColumn Property, ShowValueColumn Property.
• Using the SizingGrip Property, you can specify whether a sizing handle (grip) is displayed in the lower-right corner of the control.

The features available to the interactive user are a combination of the features provided by the UADataSetHeaderControl and the UAFieldDataDictionaryControl.