Using a ListView Control to Select Trends to Display

Multiple trends can be viewed on a Trend Tool simultaneously. This functionality can allow the user to dynamically select one or more trends to view, if script is provided to do so. Several list controls could be used in this situation to display the set of values to trend, including a List Box, a set of Check Buttons, or any ActiveX list control.

The following example uses a Microsoft ListView Control (ActiveX) to take advantage of its option to show check boxes next to list items. It is assumed that the Site/Service and Facility are configured at the View level.

Using a ListView Control (ActiveX) to enable Display of Single or Multiple Trends

  1. Create a new Studio screen.
  2. Place a ListView control on the screen.
  1. Click the ActiveX tool ActiveX tool on the Standard Tools palette.
  2. Click and drag the outline of the list box on the screen. When the mouse button is released, an Insert OLE Control dialog box appears.
  3. In the dialog box, select Microsoft ListView Control.  The version number may be included in the name.
  4. Right-click the control to open its properties. In the (ObjectCode) field, type "listControl."
  1. Place a Trend control on the screen.
  1. Click the Trend *Trend button on the Standard Tools palette.
  2. Click and drag the outline of the Trend control on the screen.
  3. Right-click the control to open its properties. In the (ObjectCode) field, type "trendControl."
  1. Add general declarations.
  1. Open the Script Editor and navigate to (General), (Declarations).
  2. Enter the following script. Note that trend series are stored in a two dimensional array, where for each series, the list item, long point ID, and UDC, and axis number are stored in that order.

'(Declarations)

 

'Set up trend colors

Dim trendColors(3)

trendColors(0) = vbRed

trendColors(1) = vbBlue

trendColors(2) = vbGreen

 

'Initialize trend series array

Dim SeriesArray(3,3)

 

'Method to add a series to the array and trend control

Sub AddTrendSeries(longPointID, axisNum, listItem, udc)

SeriesArray(axisNum, 0) = listItem

SeriesArray(axisNum, 1) = longPointID

SeriesArray(axisNum, 2) = udc

SeriesArray(axisNum, 3) = axisNum

 

'Update trend control

With trendControl

.SiteService(axisNum) = TheView.SiteService

.FacilityId(axisNum) = TheView.Facility

.Udc(axisNum) = udc

.AutoScale(axisNum) = True

.OverlayYAxis(axisNum) = False

.PointIdLong(axisNum) = longPointID

.XAxisLabel = "Time"

.SeriesColor(axisNum) = trendColors(axisNum)

.LineType = 9 "Medium Thin Solid

.Restart()

End With

End Sub

 

'End of (Declarations)
  1. Add initialization script to the ListView Control.
  1. In the Script Editor, navigate to the listControl EventInitialize event.
  2. Enter the following script. Successive columns are defined as sub items of the first column. The second column (UDC) is used to store the UDC value for each item, and can be made invisible if desired.

Sub listControl_EventInitialize()

Dim This : Set This = listControl

This.Checkboxes = True

This.View = 3 'Report view

 

'Add columns

This.ColumnHeaders.Add , , "Choose one or more items to trend"

This.ColumnHeaders.Add , , "UDC"

 

'Add descriptions in first column (changes these descriptions to match your application)

With This.ListItems

.Add , , "Vol Gas Today"

.Add , , "Vol Gas Yest"

.Add , , "Gas Rate"

End With

 

'Add UDCs in second column (change to match your application)

With This

.ListItems(1).SubItems(1) = "VGT"

.ListItems(2).SubItems(1) = "VGY"

.ListItems(3).SubItems(1) = "RGAS"

End With

End Sub
  1. Click OK to close the script editor.
  1. Add script to run when a user checks or unchecks an item in the ListView.
  1. Still in the Script Editor, navigate to the listControl EventItemCheck event.
  2. Enter the following script. This event has one parameter, Item, the list item that called the event after being checked or unchecked.

Sub listControl_EventItemCheck(Item)

Dim This : Set This = listControl

If Item.Checked = True Then

longPointID = TheView.Facility & "_" & Item.SubItems

For i = 0 To ubound(SeriesArray)

If SeriesArray(i, 0) = "" Then 'Fill in first empty spot

AddTrendSeries LongPointID, i, Item, Item.SubItems(1)

Exit For

End If

Next

Else 'Remove from series array

For i = 0 To ubound(SeriesArray)

If SeriesArray(i, 0) = Item Then

trendControl.DeleteSeries(SeriesArray(i, 3))

SeriesArray(i, 0) = ""

SeriesArray(i, 1) = ""

SeriesArray(i, 2) = ""

SeriesArray(i, 3) = ""

Exit For

End If

Next

ReIndexSeriesArray

End if

End Sub
  1. Save the screen and switch to Run mode. Assuming that sufficient data values exist for the given UDCs, try turning series trends on and off to see the Trend control updated accordingly.

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