Added new kb article dpl-resolve-ambiguous-references

Author: KB Bot

knowledge-base/dpl-resolve-ambiguous-references.md

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+---
+title: Resolving Ambiguous references
+description: This article describes how to resolve ambiguous references due to cross-platform project references.
+type: how-to
+page_title: How to Resolve Ambiguous References
+slug: dpl-resolve
+tags: radspreadprocessing, document processing, wpf, ambiguous reference, extern alias
+res_type: kb
+ticketid: 1684241
+---
+
+## Environment
+
+| Version | Product | Author | 
+| ---- | ---- | ---- | 
+| 2025.1.205| Telerik Document Processing|[Desislava Yordanova](https://www.telerik.com/blogs/author/desislava-yordanova)| 
+
+## Description
+
+When developing a WPF application that utilizes RadSpreadProcessing for Document Processing to set a font in a spreadsheet, and the solution includes a cross-platform project referencing `Telerik.Documents.Core`, an ambiguous reference error may occur. The issue arises due to identical namespaces in both assemblies when both platform-specific projects and cross-platform projects are part of the solution. This knowledge base article also answers the following questions:
+- How to resolve ambiguous reference errors in a WPF project using RadSpreadProcessing?
+- How to use RadSpreadProcessing in a WPF application with cross-platform project references?
+- How to set a spreadsheet font in WPF using RadSpreadProcessing without ambiguous references?
+
+## Solution
+
+To resolve the ambiguous reference error in a WPF application using RadSpreadProcessing alongside a cross-platform project, use the `extern alias` directive. This approach allows differentiating between assemblies that have the same namespace but are intended for different platforms. Follow the steps below to apply this solution:
+
+1. **Assign an alias to the conflicting assembly in the WPF project**. Right-click on the referenced assembly (`Telerik.Documents.Core` in the cross-platform project) in the Solution Explorer and select `Properties`. In the `Aliases` field, enter a unique alias (e.g., `NetFramework`).
+
+2. **Use the `extern alias` directive in your WPF project code**. At the top of your C# file where you are facing the ambiguous reference, declare the alias defined in step 1. This explicitly specifies which assembly to use for the conflicting types.
+
+```csharp
+extern alias NetFramework;
+using NetFramework::Telerik.Documents.Common.Model;
+```
+
+3. **Reference the `ThemableFontFamily` using the alias**. After specifying the extern alias, use it to qualify the namespace of the `ThemableFontFamily` class or any other ambiguous type. This disambiguates the reference and allows your code to compile successfully.
+
+```csharp
+namespace YourNamespace
+{
+    public class YourClass
+    {
+        public void YourMethod()
+        {
+            // Use the ThemableFontFamily from the aliased assembly
+            ThemableFontFamily fontFamily = new ThemableFontFamily("Courier New");
+        }
+    }
+}
+```
+
+By following these steps, you can successfully resolve the ambiguous reference error and set the spreadsheet font in a WPF application using RadSpreadProcessing, even when your solution includes cross-platform projects.
+
+## See Also
+
+- [Telerik Document Processing Introduction](https://docs.telerik.com/devtools/document-processing/introduction)
+- [What Versions of Document Processing Libraries are Distributed with the Telerik Products](https://docs.telerik.com/devtools/document-processing/knowledge-base/distribute-telerik-document-processing-libraries-net-versions)
+- [Resolve Compile-Time Error Between RadPdfProcessing and Telerik Reporting](https://docs.telerik.com/devtools/document-processing/knowledge-base/resolve-compile-time-error-radpdfprocessing-telerik-reporting)
+- [C# Extern Alias - Microsoft Documentation](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/extern-alias)