C1MultiDocument IndexOutOfRangeException error on WinForms .Net 8+

Posted by: hrvoje.zirdum on 11 March 2026, 9:03 am EST

  • Posted 11 March 2026, 9:03 am EST - Updated 11 March 2026, 9:08 am EST

    Hi all :slight_smile:

    After I upgraded the C# WinForms project from .Net Framework 4.8.1 to .Net 8, then 9 and 10, an error started appearing when using C1MultiDocument. In my project, the error “IndexOutOfRangeException: Index was outside the bounds of the array” occurs. in this part of the code this.c1PrintPreviewControl1.Document = this.multiDoc;

    Attached is the same error that appears on your MultiDocumentFilesprint example that comes with the Mescius controls installation.

    I am using the latest version of Mescius WinForms controls with Visual Studio 2022 and 2026.

    Can you help me solve this problem?

    Regards,

    Hrvoje

  • Posted 12 March 2026, 8:49 am EST

    Hello Hrvoje,

    We were able to reproduce this behavior on our end using the MultiDocumentFilesPrint sample you mentioned.

    We have escalated the behavior to the development team and will get back once we have more information. [Internal Tracking ID: C1WIN-35103]

    Regards,

    Uttkarsh.

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