Low memmory. What to do?

Hey, I have made app, which repaints and changes wallpaper after some period. But something goes wrong. Every time then function is called ~7 MB of memory are "ate". How to free it after doing job? I tried dispose, but nothing.

VB Code:

Public Function Paint_text(ByVal txt As String) As Bitmap
 
Dim bm_source As New Bitmap(Image.FromFile("C:\piv.bmp"))
Dim bm_dest As New Bitmap(CInt(bm_source.Width), CInt(bm_source.Height)
Dim gr_dest As Graphics = Graphics.FromImage(bm_dest)
gr_dest.DrawImage(bm_source, 0, 0, bm_dest.Width, bm_dest.Height)
 
Dim mybrush As New Drawing2D.LinearGradientBrush(ClientRectangle, FontDialog1.Color, FontDialog1.Color, Drawing2D.LinearGradientMode.Horizontal)
 Dim myFont As New Font("Verdana",  12, FontStyle.Regula)
gr_dest.DrawString(txt, myFont, mybrush, New RectangleF(x1 , y1 , x2 - x1, y2 - y1)
Paint_text = bm_dest
 
        gr_dest.Dispose()
        mybrush.Dispose()
        mypen.Dispose()
        myFont.Dispose()
        bm_source.Dispose()
        bm_source = Nothing
        bm_dest = Nothing
 
    End Function

Then I set returned image to picturebox (~3MB). But it's OK. This is not why after every function call memory isn't cleared.

Hi,

I think your function is holding the buffer. Try to clear the buffer by using "Paint_text=Nothing"after you have transfer the data to somewhere....

try using the "unlockbits" method of your new object

Hi.

This is a no-no and a bad way of doing things, but it works. :rolleyes:

Use GC.Collect.

That will force the garbagecollector to clean up.
I have had a few situations where I used som API BitBlt'ing, and for some reason I couldn't get it to release my memory even though I did release HDC's and Destroy and everything else I could think of to clean up.

The only way I could solve this (on my own, anyway...) was using GC.Collect.

Can you give me an exmaple, how to use it?

Hi.

Just put it in the end of you function.

VB Code:

Public Function Paint_text(ByVal txt As String) As Bitmap
 
Dim bm_source As New Bitmap(Image.FromFile("C:\piv.bmp"))
Dim bm_dest As New Bitmap(CInt(bm_source.Width), CInt(bm_source.Height)
Dim gr_dest As Graphics = Graphics.FromImage(bm_dest)
gr_dest.DrawImage(bm_source, 0, 0, bm_dest.Width, bm_dest.Height)
 
Dim mybrush As New Drawing2D.LinearGradientBrush(ClientRectangle, FontDialog1.Color, FontDialog1.Color, Drawing2D.LinearGradientMode.Horizontal)
 Dim myFont As New Font("Verdana",  12, FontStyle.Regula)
gr_dest.DrawString(txt, myFont, mybrush, New RectangleF(x1 , y1 , x2 - x1, y2 - y1)
 
        gr_dest.Dispose()
        mybrush.Dispose()
        mypen.Dispose()
        myFont.Dispose()
        bm_source.Dispose()
        bm_source = Nothing
 
GC.Collect
 
Paint_text = bm_dest
    End Function

You might have noticed that I have moved Paint_Text=bm_Dest to the bottom and deleted the bm_dest=Nothing.

Usually you would use Return bm_Dest and that would exit the function, and your dispose commands would not be called.
So always dispose everything you can before returning the result.