Hello, I' have a problem:
First I tell you what the aim is: I make a visualisation of a machine. On loading the visualisation form, i make new pictureboxes with the picture of (for example) a grey motor. In my main form, I make a connection with a PLC. Every 500ms I get an update from the status of the machine. The main form checks what elements had changed, and if they are used in this visualisation form, update them in this form. Now the problem is to select this exact picturebox, to change its picture to (for example) a green or red motor when the status is on or fault.
Here the code on for making the new pictureboxes:
Public Sub NewPicture(ByVal ID As Integer, ByVal Type As Integer, ByVal PositieX As Integer, ByVal PositieY As Integer, ByVal Tooltip As String) 'Create the picture Dim Pic As New PictureBox 'Specify the location and te sizePic.Location =
New System.Drawing.Point(PositieX, PositieY)Pic.Size =
New System.Drawing.Size(100, 100)Pic.SizeMode = PictureBoxSizeMode.AutoSize
Pic.Name =
"Pic" & Str(ID)Pic.Image = Tekening_Ophalen(Type, 0)
'this function selects the type of picture: small motor/medium motor/Blower, ....Pic.BackColor = Color.Transparent
Pic.BorderStyle = BorderStyle.None
ToolTipVisualisatieElementen.SetToolTip(Pic, Tooltip)
'Add it to the forms control collection Me.Controls.Add(Pic) 'Link the event to the event handler AddHandler Pic.Click, AddressOf Me.VisualisationElementClick End SubThe code for loading the form:
Private Sub FrmVisualisatieBiologie_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim teller As Integer For teller = 0 To aantal_VisualisatieElementen - 1 ' Call NewPicture(VisElBiologie(teller).ID, VisElBiologie(teller).Type, VisElBiologie(teller).Positie.X, VisElBiologie(teller).Positie.Y, VisElBiologie(teller).Tooltiphelp) Next End SubSo far so good, this works...
Now the aim is that the main form gives a list of elements that were the status was changed in the way or an array with 2 colums : (VisElBiologie().ID, Status).
Public Sub Update_Status(ByVal ID() As Integer, ByVal Status() As Integer) Dim Teller As Integer Dim Pic As PictureBoxPic.Name =
"Pic" & Str(ID(Teller)) For Teller = 0 To ID.Length - 1Pic.Image = Tekening_Ophalen(ID(Teller), Status(Teller))
Next End SubHow can I assign this pic to the previous created picturebox (see The fault given is the folowing: "Warning 1 Variable 'Pic' is used before it has been assigned a value. A null reference exception could result at runtime."
Thanks in advance
Paul
Select runtime made controls
Dan L
Solution Found !!!!
Public Sub Update_Status(ByVal ID() As Integer, ByVal Status() As Integer) Dim Teller As Integer Dim Teller1 As Integer Dim Pic As PictureBox Dim lstControls As Control() Dim Naam As String For Teller = 0 To ID.Length - 1 'Counter Teller loops through all the changed elementsNaam =
"Pic" & Format(ID(Teller), "0000") 'Create the name of how the picturebox should be like lstControls = Me.Controls.Find(Naam, True) For Teller1 = 0 To lstControls.Length - 1 'LstControls = List of all the controls with this namePic = lstControls(Teller1) 'Assign picturebox to a control in the list of controls
Pic.Image = Tekening_Ophalen(ID(Teller), Status(Teller))
'this function selects the type of picture: small motor/medium motor/Blower, .... and its state: 0=OFF, 1=ON, 2=Fault, ... Next Next End SubMrBradford
Perhaps you would do it the other way around:
For the visible form, go through all the controls which need updating and grab the appropriate Data Point. You can store information in the TAG of each object which references the data source (This Tag object can reference pretty much anything). In this way, you don't need a reference to the control, and each Data Point can actually update the status of multiple Controls.