Add missing FAQS in XlsIO UG

Document-Processing/Excel/Excel-Library/NET/faqs/how-to-prevent-parse-exception-from-undefined-named-ranges.md

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+---
+title: Prevent ParseException when updating formulas | Syncfusion
+description: This page explains how to prevent ParseException when modifying formulas with undefined named ranges in Syncfusion .NET Excel library (XlsIO).
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# How to prevent ParseException from undefined named ranges?  
+
+To prevent a ParseException when modifying formulas that reference undefined named ranges, set the <a href="https://help.syncfusion.com/cr/document-processing/Syncfusion.XlsIO.IWorkbook.html#Syncfusion_XlsIO_IWorkbook_ThrowOnUnknownNames">ThrowOnUnknownNames</a> property to **false** before updating the formula.
+
+{% tabs %}  
+{% highlight c# tabtitle="C# [Cross-platform]" %}
+workbook.ThrowOnUnknownNames = false;
+{% endhighlight %}
+
+{% highlight c# tabtitle="C# [Windows-specific]" %}
+workbook.ThrowOnUnknownNames = false;
+{% endhighlight %}
+
+{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
+workbook.ThrowOnUnknownNames = False
+{% endhighlight %}
+{% endtabs %}
+
+This ensures that formulas with undefined named ranges won't trigger errors during assignment or modification.

Document-Processing/Excel/Excel-Library/NET/faqs/what-is-the-maximum-character-limit-for-an-Excel-cell.md

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+---
+title: Maximum characters allowed in Excel cell | Syncfusion
+description: Learn about the maximum number of characters supported in a single Excel cell using Syncfusion .NET Excel library (XlsIO).
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# What is the maximum character limit for an Excel cell?
+
+A single Excel cell can contain up to **32,767 characters**. 

Document-Processing/Excel/Excel-Library/NET/faqs/what-is-the-maximum-number-of-hyperlinks-in-an-Excel-worksheet.md

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+---
+title: Maximum number of hyperlinks in Excel worksheet | Syncfusion
+description: Learn about the maximum number of hyperlinks supported in an Excel worksheet using Syncfusion .NET Excel library (XlsIO).
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# What is the maximum number of hyperlinks in an Excel worksheet?
+
+An Excel worksheet can contain up to **65,530 hyperlinks**. This limit ensures compatibility with Excel's internal structure and helps maintain performance when working with large datasets.