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POArgumentNullException was unhandled - Value cannot be null. Parameter name: first
 

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    <p>I am currently using the DotSpatial library for .NET (GIS Library). I am getting an error within my AppManager class. The AppManager is a Component that manages the loading of extensions (including data providers), and helps with file serialization:</p> <p><strong>Code being flagged at foreach</strong></p> <pre><code>public IEnumerable&lt;string&gt; GetDirectoriesNestedOneLevel() { // Visit each directory in Directories Property (usually set by application) foreach (string directory in Directories.Union(new[] { "Data Extensions", "Tools" })) { string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, directory); if (Directory.Exists(path)) { yield return path; // Add all of the directories in here, nested one level deep. var dirs = Directory.EnumerateDirectories(path, "*", SearchOption.TopDirectoryOnly); foreach (var dir in dirs) { yield return dir; } } } } </code></pre> <p><strong>ParamName</strong> </p> <blockquote> <p>first</p> </blockquote> <p><strong>Source</strong> </p> <blockquote> <p>System.Core</p> </blockquote> <p><strong>StackTrace</strong></p> <blockquote> <p>at System.Linq.Enumerable.Union[TSource](IEnumerable<code>1 first, IEnumerable</code>1 second) at DotSpatial.Controls.AppManager.d__9.MoveNext() in c:\dev\DotSpatial\DotSpatial.Controls\Extensions\AppManager.cs:line 581 at DotSpatial.Controls.AppManager.GetCatalog() in c:\dev\DotSpatial\DotSpatial.Controls\Extensions\AppManager.cs:line 563 at DotSpatial.Controls.AppManager.LoadExtensions() in c:\dev\DotSpatial\DotSpatial.Controls\Extensions\AppManager.cs:line 329 at DemoMap.MainForm..ctor() in C:\Users\Logan B. Lehman\Documents\DemoMap\DemoMap\MainForm.cs:line 230 at DemoMap.Program.Main() in C:\Users\Logan B. Lehman\Documents\DemoMap\DemoMap\Program.cs:line 13 at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()<br> at System.Threading.ThreadHelper.ThreadStart_Context(Object state)<br> at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()</p> </blockquote> <p><strong>Any idea on what is going on here?</strong> *<em>It would be more than appreciated</em>*</p>
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    1. USJohn Saunders
    1. USLogan B. Lehman
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      1. USJohn3136
 

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