Exporting Excel Range as image (VB.NET)

问题:

I have a working excel vba macro that does what I want from here and I am trying to convert it to VB.NET.

The code from VBA:

Sub bah()
''' Set Range you want to export to file
    Dim rgExp As Range: Set rgExp = Range("B2:C6")
    ''' Copy range as picture onto Clipboard
    rgExp.CopyPicture Appearance:=xlScreen, format:=xlBitmap
    ''' Create an empty chart with exact size of range copied
    With ActiveSheet.ChartObjects.Add(Left:=rgExp.Left, Top:=rgExp.Top, _
    Width:=rgExp.Width, Height:=rgExp.Height)
    .Name = "ChartVolumeMetricsDevEXPORT"
    .Activate
    End With
    ''' Paste into chart area, export to file, delete chart.
    ActiveChart.Paste
   ActiveSheet.ChartObjects("ChartVolumeMetricsDevEXPORT").Chart.Export "C:\Users\ajohnson\Desktop\workdamnit.jpg"
ActiveSheet.ChartObjects("ChartVolumeMetricsDevEXPORT").Delete
End Sub

What this does is take an excel range and then put it into a chart that is a copy of the range and save it as a JPG.

Here is my most recent attempt at making it VB.NET:

Dim xlApp As New Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
Dim xlRange As Excel.Range
xlWorkBook = xlApp.Workbooks.Open("C:\test.xlsx")
xlWorkSheet = xlWorkBook.Sheets("Sheet1")


 xlRange = xlWorkSheet.Range("B2:C6")
        With xlWorkSheet.ChartObjects.add(xlRange.Left, xlRange.Top, xlRange.Width, xlRange.Height)
            .name = "Chart1"
            .activate()
        End With
xlWorkSheet.ChartObjects("Chart1").Paste()
        xlWorkSheet.ChartObjects("Chart1").chart.export(Filename:="C:\Users\ajohnson\Desktop\saveit.jpg")
        xlWorkSheet.ChartObjects("Chart1").delete()

I am running into trouble converting the ActiveChart.Paste method. I can't get it to work in VB.NET. It either throws an error or It just leaves an empty box when I do it in VB.NET (if I add .chart before the paste it runs, but doesn't paste any values), but in VBA it fills in the values of interest. I have tried creating a chart object, but that did not seem to work either.

I feel like I am close to having it sorted out, but I can't quite get it. I suppose I could leave it as a VBA macro and call it from VB.NET, but that seems absurd on some level. Any help would be greatly appreciated. I am also open to different approaches, its just this is the thing I came across that worked well in VBA, so I figured it was a good starting point.

Thanks as always!

回答1:

I just had to hit the MSDN up a little harder to get there. Turns out you have to put the chartobject inside a chart, the code I got working looks like:

  xlRange = xlWorkSheet.Range("B2:C6")
    xlRange.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlPicture)
    Dim oChtobj As Excel.ChartObject = xlWorkSheet.ChartObjects.add(xlRange.Left, xlRange.Top, xlRange.Width, xlRange.Height)
    Dim oCht As Excel.Chart
    oCht = oChtobj.Chart
    oCht.Paste()
    oCht.Export(Filename:="C:\saveit.jpg")
    oChtobj.Delete()

I was going to delete the question, since it got solved by me so quickly (this ignores the decent bit of time I spent before I posted it here), but when I search for a problem like mine it comes to this page, so maybe this will help someone in the future. If you are looking to copy a range from excel to a jpg for some reason (perhaps attaching it to the body of an outlook email, because that is what I am doing), this should work for you.

回答2:

And the C# equivalent requires the call to Activate() or COMException will be thrown

Excel.Range xlRange = xlWorkSheet.Range("B2:C6");

range.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlPicture);
Excel.ChartObject chartObj = myWorksheet.ChartObjects().Add(range.Left, range.Top, range.Width, range.Height);

chartObj.Activate();  // Don't Forget!

Excel.Chart chart = chartObj.Chart;
chart.Paste();
chart.Export(@"C:\image.png");

chartObj.Delete();