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Compiler Error CS0155 

Error Message

The type caught or thrown must be derived from System.Exception

An attempt was made to pass a data type that does not derive from System.Exception into a catch block. Only data types that derive from System.Exception can be passed into a catch block. For more information, see Exception Handling Statements and Exceptions and Exception Handling (C# Programming Guide).

The following sample generates CS0155:

// CS0155.cs
using System;

namespace MyNamespace
{
    public class MyClass2
    // try the following line instead
    // public class MyClass2 : Exception
    {
    }
    public class MyClass
    {
        public static void Main()
        {
            try
            {
            }
            catch (MyClass2)   // CS0155, resolves if you derive MyClass2 from Exception
            {
            }
        }
    }
}
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