Why does the ID error occur when attempting to add multiple records in C# WPF application?

Question

I'm developing a .net application with C# WPF. When I try to add new consecutive records without closing the window, I encounter the following error. When I try to record the values entered by the user into the database with the NewReader object connected on the XAML side, I cannot add more than one record. I have to close the window and open it again. When I fill the NewReader object on the code side, I can add multiple records without any problems. What could be the reason for this situation? How can I fix the error?

Thanks.

Exception:

Microsoft.EntityFrameworkCore.DbUpdateException: 'An error occurred while saving the entity changes. See the inner exception for details.' "UNIQUE constraint failed: Readers.Id"

Answer 1

Hi,@fatih uyanık. Welcome to Microsoft Q&A Forum.

The error you are encountering seems to be related to violating a unique constraint on the Id field in the Readers table. This error typically occurs when you are trying to insert a record with an Id value that already exists in the table. If you're attempting to add new records without closing the window, you might be reusing the same Id value inadvertently.

To fix this error, you need to ensure that each new record has a unique Id value when it is added to the database. You could try the following steps:

Check your database schema to ensure that the Id field is set to auto-increment or is generated automatically to guarantee uniqueness. Ensure that you are not explicitly setting the Id value when creating a new Readers object before saving it to the database. Let the database handle the generation of the Id automatically.

Double-check your application logic to ensure that you are not inadvertently using the same Id value for different records. If you are manually assigning Id values, make sure they are unique for each new record.

Here's an example of how to create a new Readers object without setting the Id explicitly:

using (var context = new YourDbContext())
{
    var newReader = new Readers
    {
        // Set other properties here
        // Id will be automatically generated by the database
    };

    context.Readers.Add(newReader);
    context.SaveChanges();
}

If the problem persists, it may help to check your code and database settings.

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