Small Problem...

[dcahrakos]

well im trying to get it so when a persons mouse goes into a picture box, which I have named as prender, a box is drawn around the mouse, and then it follows the mouse, the code I have is this

Private Sub prender_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles prender.MouseMove
Dim p As Pen
Dim g As Graphics
g.DrawRectangle(p, e.X, e.Y, 40, 40)
End Sub

this all builds, and everything, but when i try it in the app, I get a Object reference not set to an instance of an object error...

can someone help me with this I havent used GDI much, so im not firmiliar that much with it.

 

[thenerd]

Youre not initializing G or P.

Try:

Private Sub prender_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles prender.MouseMove
Dim p As Pen
p = new pen(color.black)
Dim g As Graphics
g = new graphics(prender.creategraphics)
g.DrawRectangle(p, e.X, e.Y, 40, 40)
Also, this wont draw the rectangle around the mouse.  to make the rectangle around the mouse, youd want
g.drawrectangle(p,e.x - 20,e.y - 20,40,40)
End Sub

 

[dcahrakos]

doh....I knew I was forgetting something, im still to use to VB6....oh well, thanks alot

edit, it doesnt really work, it gives me an error
System.Drawing.Graphics.Private Sub New(nativeGraphics As System.IntPtr) is not accessible in this context because it is Private.

that happens at g = New Graphics(prender.CreateGraphics)

 

[snarfblam]

The CreateGraphics method, um, creates a graphics object for you. You do not have to use the New keyword.
[VB]
Wrong: You are passing a graphics object to the graphics constructor
(If you look at intellisense or the object browser, you will see that graphics has no
public constructor).
g = New Graphics(prender.CreateGraphics)
Right
g = prender.CreateGraphics()
[/VB]

 

[dcahrakos]

thanks, that works perfectly, although its not the way I thought it would respond, but I got it to work the way I wanted now.

edit: actually, one other quick question while were still on the same subject, say if I wanted to draw the same rectangle when the mouse just stays in one spot, how would I do that, I tried mousehover, but it doesnt have any X,Y coordinates to draw the rectangle at.

 

[Machaira]

The rectangle should stay there until you move the mouse.