Infralution Support

[Andrew Rowley]

I am implementing printing for my application which uses Virtual Trees (version 2.7.0) and have run into a couple of problems.

1) If I use the same VirtualTreePrintDocument to print different trees (changing the Tree property) it doesn't work properly. It seems to retain various information from the previous tree. I was trying to use the same printdocument to retain any change that the user might make to the print settings.

2) Printing an empty tree seems to be different to displaying an empty tree.
The tree has an ArrayList as the root row, and ShowRootRow set to false.
I have a GetCellData event to selectively hide information in some rows.
When printing, if the ArrayList has no data GetCellData is called for the root row, and GetCellBinding for the row returns null. If the ArrayList contains data, GetCellData is not called for the root row.
Also, if the ArrayList is empty, 2 pages are printed with identical headers and footers, except for the page number. If there is data, only a single page is printed.

The problems occur for both print and print preview.

[Infralution]

[Andrew Rowley]

According to the .NET documentation, a PrintDocument is reusable. I have seen recommendations to reuse the PrintDocument each time you print, to maintain any settings the user may have changed.

Trying to save the settings is a bit difficult as it seems to be a hall of mirrors - PrintDocument.DefaultPagesettings.PrinterSettings, PrintDocument.PrinterSettings.DefaultPageSettings etc. - hence the recommendation to reuse the PrintDocument.

It is a bit of a limitation if the VirtualTreePrintDocument doesn't support it. Even if you could just save the base PrintDocument and use it to construct a new VirtualTreePrintDocument it would be helpful.

I have created a project that demonstrates the double page problem and sent it to you.

[Infralution]

We'll have a look at the sample project and get back to you sometime next week.
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Infralution Support

[Infralution]

Thanks for the sample project - it helped to track down the issues.

There is indeed a bug when ShowRootRows is false and the tree being printed is empty that causes two pages to be printed (the second with the root row displayed). We will fix this with a release in the next day or two.

We also took a look at the issue of reusing VirtualTreePrintDocument for multiple prints. This seems to be OK as long as you are printing the same tree object. If you print a different tree object then the VirtualTreePrintDocument retains the columns from the previous tree. You can work around this by setting the VirtualTreePrintDocument.Columns = null when you set the Tree property. This forces the print document to get the visible columns from the tree again. We will also change this in the next release so that changing the tree object does this automatically.
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Infralution Support

[Infralution]

We have now released versions 2.7.1 and 3.5.1 of Virtual Tree which fixes these issues.
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Infralution Support

[Andrew Rowley]

Thanks.