unable to draw line

[alaric]

[RESOLVED] unable to draw line

Hi,

I know how to draw a line

[SIZE=2][COLOR=#0000ff]
Dim[/COLOR][/SIZE][SIZE=2] DrawLine [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Drawing.Graphics
DrawLine = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].CreateGraphics[/SIZE]
[SIZE=2][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] PenColor [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] System.Drawing.Pen(System.Drawing.Color.Black)
[/SIZE][/SIZE]

now I want to position this line just above a label (which is in a groupbox)
so I thought:

[SIZE=2][COLOR=#0000ff]
[SIZE=2][COLOR=#008000]'get location X,Y of the groupBox)
[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] posX1 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].grpFactAanmaak.Location.X
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] posY1 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].grpFactAanmaak.Location.Y
[/SIZE][SIZE=2][COLOR=#008000]'get location X,Y of the label)
[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] posX2 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].lblCurTotaal.Location.X
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] posY2 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].lblCurTotaal.Location.Y
[/SIZE][SIZE=2][COLOR=#008000]'Me.lblCurTotaal.Location = New System.Drawing.Point(120, 160)
[/COLOR][/SIZE][SIZE=2][COLOR=#008000]'calc the start X, Y pos of the line
[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] ActposX [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = posX2 + posX1
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] ActposY [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = posY2 + posY1
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] DrawLine [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Drawing.Graphics
DrawLine = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].CreateGraphics
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] PenColor [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] System.Drawing.Pen(System.Drawing.Color.Black)[/SIZE]
[SIZE=2][COLOR=#008000]'draw the line 10 px above the label and length 30 px[/COLOR]
DrawLine.DrawLine(PenColor, ActposX, ActposY - 10, ActposX + 30, ActposY - 10)
[/SIZE][/COLOR][/SIZE]

But there's NO line!

what Im I doing wrong here?

thanks in advance

 

[vis781]

are you doing this in the forms paint event or the groupbox's paint event?

 

[alaric]

thanx for your quick reply and your suggestion

iwas doing this in the form's paint event?

[SIZE=2][COLOR=#0000ff]
Private[/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] frmInschrijven_Paint([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Windows.Forms.PaintEventArgs) [/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]MyBase[/COLOR][/SIZE][SIZE=2].Paint
[/SIZE]

i changed it to

[SIZE=2]
[/SIZE][SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2] grpFactAanmaak_Paint([/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] sender [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] [/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2], [/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2] e [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Windows.Forms.PaintEventArgs) [/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2] grpFactAanmaak.Paint
[/SIZE]

but now my form is not displayed completeley, looks like its rendering or something...

 

[vis781]

sounds a bit odd, what exactly do you mean when you say it's not displaying correctly.

 

[alaric]

sorry for the inconvenience but I changed the code to:

[COLOR=#0000ff]
Dim[/COLOR] L1 [COLOR=#0000ff]As[/COLOR] System.Drawing.Graphics
L1 = [COLOR=#0000ff]Me[/COLOR].CreateGraphics
[COLOR=#008000]'Use a red pen color to draw a line
[/COLOR][COLOR=#0000ff]Dim[/COLOR] PenColor [COLOR=#0000ff]As[/COLOR][COLOR=#0000ff]New[/COLOR] System.Drawing.Pen(System.Drawing.Color.Black, 10)
L1.DrawLine(PenColor, ActposX, ActposY - 10, ActposX + 30, ActposY - 10)

i used drawline instead of L1 for the linevariable. drawline is (offcourse) not valid.

Now the form comes up, but No line in the groupbox.
these are the calculated coordinates (console.writeline)
actposx -> 576
actposy -10 ->586
actposx +30 -> 606
actposy -10 -> 586

 

[vis781]

Sounds like rather big group box to me. Are you using the co-ordinates for the label in relation to the form, or it's co-ordinates relative to it's container i.e the groupbox.

 

[alaric]

you are right.
The first time I didnt see my line, I thought I calculate the coordiantes like start X, Y of the grpBox and add start X,Y of the label inside this groupbox , in order to calc the startingpoint of my line. this was when i used the paintevent of the form

now i use the paint event of the grpbox.

but whats the best/easiest way?
if I change the coordinates rel to the grpbox... still no line

 

[vis781]

This is something that i observe many people do. What you have in the paint event is a graphics object that is ready to draw on so you don't need to create a new graphics object.

ByVal e as system.blah, blah painteventargs

So it should be

e.graphics.drawline(etc.....)

With me?

 

[alaric]

thanks so far,

i think I lost you. Do you mean that I dont need a the sub

[SIZE=2]
[/SIZE][SIZE=2][COLOR=#0000ff][SIZE=2][COLOR=#0000ff]Private[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Sub[/COLOR][/SIZE][SIZE=2][COLOR=#000000] grpFactAanmaak_Paint([/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2][COLOR=#000000] sender [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Object[/COLOR][/SIZE][SIZE=2][COLOR=#000000], [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]ByVal[/COLOR][/SIZE][SIZE=2][COLOR=#000000] e [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#000000] System.Windows.Forms.PaintEventArgs) [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Handles[/COLOR][/SIZE][SIZE=2][COLOR=#000000] grpFactAanmaak.Paint[/COLOR]
[/SIZE][/COLOR][/SIZE]

but just instead
(just somewhere ie load form event)?

i tried (on the form load event):

[SIZE=2][COLOR=#0000ff]
Dim[/COLOR][/SIZE][SIZE=2] posX2 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].lblCurTotaal.Location.X
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] posY2 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Single[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].lblCurTotaal.Location.Y
[/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] L1 [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] System.Drawing.Graphics
L1 = [/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE][SIZE=2].CreateGraphics
[/SIZE][SIZE=2][COLOR=#008000]' 'Use a red pen color to draw a line
[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] PenColor [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] System.Drawing.Pen(System.Drawing.Color.Black)
L1.DrawLine(PenColor, posX2, posY2 - 10, posX2 + 30, posY2 - 10)
[/SIZE]

still no luck
it seems that I just dont understand the techniek

 

[vis781]

Yes you do need your groupbox paint sub. This handles all the painting for the control. So you need to put all your code for painting in there so it will go something like this......

PrivateSub grpFactAanmaak_Paint(ByVal sender AsObject, ByVal e As System.Windows.Forms.PaintEventArgs) Handles grpFactAanmaak.Paint
 
Dim posX2 AsSingle = Me.lblCurTotaal.Location.X
Dim posY2 AsSingle = Me.lblCurTotaal.Location.Y
' 'Use a red pen color to draw a line
Dim PenColor AsNew System.Drawing.Pen(System.Drawing.Color.Black)
e.Graphics.DrawLine(PenColor, posX2, posY2 - 10, posX2 + 30, posY2 - 10)

 

[alaric]

thank!!! that worked