Hugh Memory Problem using DataGridView

[eblattner]

Hey all. I have a problem displaying a binary file in a DataGridView control. This program is basically a binary editor/mapper for automotive PCM files. Loading the file in to the array is very fast (less than 5 seconds), displaying in the grid is slow (no biggie), but the biggest problem I have is memory usage.

The binary files I'm reading are either 512k or 1024k. I import a file into an array, then display it in the DataGridView. This is where the problem comes, for a 512k file, this program uses about 95 megs (over the memory it used just to run). If I skip loading the datagrid, it's fine.

Here is the code...

        ReDim BinaryFile(FileLength - 1)

        For i = 0 To FileLength - 1

            b += 1
            tmpByte = r.ReadByte
            BinaryFile(i) = tmpByte

            tmp_Str = Hex$(tmpByte)

            If tmp_Str.Length = 1 Then
                tmp_Str = "0" & tmp_Str
            End If

            DataGridView1.Rows(a).Cells(b - 1).Value = tmp_Str
            If b = 16 Then
                a += 1
                MyPosition = Hex$(a)
                If MyPosition.Length < 4 Then
                    Select Case MyPosition.Length
                        Case 1
                            MyPosition = "000" & MyPosition
                        Case 2
                            MyPosition = "00" & MyPosition
                        Case 3
                            MyPosition = "0" & MyPosition
                    End Select
                End If

                b = 0
                DataGridView1.Rows.Add()
                DataGridView1.Rows(a).HeaderCell.Value = MyPosition

            End If


        Next i

If I rem out the DataGridView lines and leave everything else in this routine alone, there is no memory problem.

I am lost as to what I am doing wrong, any help is appreciated. Thanks in advance

 

[chrissie1]

So how many rows do you get?

Use a collection and databind it to the datagridview.

Christiaan Baes
Belgium

"My new site" - Me

 

[eblattner]

The grid is 16 columns by 65535 rows on a 512k file. All I need to do it display and edit the binary file, but the datagrid is the only way I know how to do this. I have seen other binary editors load the file VERY fast, but I assumed it's not loading the whole thing.

I'll try the colectionamd see how that works, it sounds like a good idea. I'm not sure exactly how, but I think I can figure it out.

 

[chiph]

Take a look at some of the 3rd party grids. Most of them have a feature called "virtual mode", where the grid calls you when it's time to display a cell. This way you don't load the entire grid up initially -- you just give it data when it calls your delegate.

Chip H.


____________________________________________________________________
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[eblattner]

As suggested above (thanks Chrissie1), I read the binary file into a dataset with pretty good results. Load time was about 1/10th as long, and the memory used was greatly reduced.

Now the problem I'm having is setting the rows' caption. I need the row header to display the row number in hex (ie. 0000, 0001, 0002, A123 ect.) When I do this, the memory problem comes back 28 megs displaying the data in the datagridview, but it goes up to 112 megs just adding the row header.