DevExpress Error 01: The control devexpress.xtraeditors.xtraform has thrown an unhandle exception in designer and has been disabled

DevExpress Error 01: The control devexpress.xtraeditors.xtraform has thrown an unhandle exception in designer and has been disabled ? 

The error message "the control `DevExpress.XtraEditors.XtraForm` has thrown an unhandled exception in designer and has been disabled" typically indicates that something went wrong while trying to load the form in the Visual Studio Designer. This could be due to several reasons, such as issues with the form's code, incorrect settings, or problems with the DevExpress library itself.

Steps to Troubleshoot and Resolve:

1. Check the Exception Details:

   - When the Designer shows an error, it usually provides a "Details" link or button. Click on it to see the exception details. The stack trace and message might give you a clue about what went wrong.

2. Compile the Solution:

   - Sometimes, simply building or rebuilding the solution can fix designer issues, especially if they are related to outdated or missing references.

   - Build > Rebuild Solution in Visual Studio.

3. Check for Constructor Code:

   - If your form's constructor (`InitializeComponent`) is doing anything more than initializing components (e.g., loading data, performing calculations), this might cause issues in the Designer. Move such code to the `Form_Load` event or another method that is not invoked by the Designer.

   - Example:     

     public MyForm()

     {

         InitializeComponent(); // Keep this line as is.

         // Move any other initialization code out of the constructor.

     }

4. Check for Third-Party Controls:

   - If you're using DevExpress controls on your form, ensure that all references to DevExpress libraries are correct and that they match the version your project is targeting. A mismatch or missing reference could cause the Designer to fail.

5. Comment Out Code:

   - Temporarily comment out sections of your form's code (especially code that runs in the constructor or property assignments) to identify what might be causing the issue.

   - Gradually uncomment the code to identify the problematic part.

6. Check for Custom Controls:

   - If your form uses custom controls or user controls, one of these controls might be causing the problem. Try loading the form in the Designer with the custom controls removed or commented out.

7. Update DevExpress:

   - Ensure that you are using the latest stable version of DevExpress. Sometimes bugs in the library can cause issues in the Designer, and updating can resolve these issues.

8. Use the `DesignMode` Property:

   - To prevent certain code from executing in the Designer, you can use the `DesignMode` property:

     if (!this.DesignMode)

     {

         // Place code here that should only run at runtime, not in the Designer.

     }

9. Clear the Designer File (.designer.cs):

   - If the designer file (`.designer.cs`) has become corrupted or contains problematic code, consider regenerating it. This can be done by removing the form controls (backup the code first), rebuilding the project, and then re-adding the controls.

10. Restart Visual Studio:

   - Sometimes, simply restarting Visual Studio can resolve the issue, especially if it’s caused by a temporary glitch or corrupted cache.

11. Reset the Designer:

   - Right-click on the form in the Solution Explorer and select View Code. Then, right-click on the form and select View Designer. This action can sometimes force the Designer to reload correctly.

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