DevExpress Error 02: Unable to cast object of type 'myDevices.SmokeMeasurement.Mexa1170.Configuration.Mexa1170ConfigurationUserControl' to type 'DevExpress.XtraEditors.XtraUserControl'

DevExpress Error 02: Unable to cast object of type 'myDevices.SmokeMeasurement.Mexa1170.Configuration.Mexa1170ConfigurationUserControl' to type 'DevExpress.XtraEditors.XtraUserControl' ?

This error message:

Unable to cast object of type 'myDevices.Devices.SmokeMeasurement.Mexa1170.Configuration.Mexa1170ConfigurationUserControl' to type 'DevExpress.XtraEditors.XtraUserControl'.

…usually means that the class Mexa1170ConfigurationUserControl does not inherit from DevExpress.XtraEditors.XtraUserControl — or there’s an issue with assembly references. Let’s troubleshoot step by step.

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1. Confirm inheritance
Check if the Mexa1170ConfigurationUserControl class properly inherits from XtraUserControl.

In Mexa1170ConfigurationUserControl.cs:

using DevExpress.XtraEditors;

namespace myDevices.SmokeMeasurement.Mexa1170.Configuration
{
    public class Mexa1170ConfigurationUserControl : XtraUserControl
    {
        public Mexa1170ConfigurationUserControl()
        {
            InitializeComponent();
        }
    }
}

If it does not inherit, you’ll see this error when you try to cast.

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2. Check for assembly mismatches
Sometimes the DevExpress assembly versions differ across projects, which can lead to casting issues. Make sure:

• All projects reference the same version of DevExpress.XtraEditors.dll.
• Use NuGet Package Manager or Reference Properties in Visual Studio to confirm this.

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3. Clean and rebuild the solution
Sometimes the issue comes from stale builds.

• Clean Solution → Rebuild Solution in Visual Studio.

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4. Ensure no duplicate DevExpress references
Check that no project references multiple versions of DevExpress.XtraEditors.dll. You can do this in the References section of your project.

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5. Check the DevExpress.XtraEditors version in the GAC
If you’re using assemblies from the GAC, sometimes older versions cause this error. You can check the versions in the GAC using:

gacutil -l DevExpress.XtraEditors

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6. Check runtime assembly binding
If your app uses different versions at runtime, add a binding redirect in your .config file:

<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="DevExpress.XtraEditors" publicKeyToken="b88d1754d700e49a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-23.1.5.0" newVersion="23.1.5.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

(Replace the version and public key token with your DevExpress version.)

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7. Confirm the object type
If you're getting the object from reflection or a dynamic source, confirm the actual type:

var control = someObject as DevExpress.XtraEditors.XtraUserControl;
if (control == null)
{
    Console.WriteLine(someObject.GetType().FullName);
}

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8. Last resort: Decompile and inspect
If nothing else works, use ILSpy or dnSpy to decompile and confirm the base class of Mexa1170ConfigurationUserControl.

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