Troubleshooting the "The operation is not valid for the state of the transaction" Error in C#

TransactionScope is a class in the .NET framework that helps you manage database transactions. It ensures that a series of database operations are treated as a single unit. This means either all the operations succeed (commit), or none of them do (rollback).

Why the error occurs:

This error arises when you try to perform an operation that's incompatible with the current state of the transaction. Here are some common reasons:

1. Nested transactions: You cannot have two active transactions nested within each other. Attempting this will lead to this error.

Example:

using (TransactionScope outerScope = new TransactionScope())
{
    // Perform some database operations

    using (TransactionScope innerScope = new TransactionScope()) // This line will cause the error
    {
        // More database operations
    }

    outerScope.Complete(); // This line will never be reached
}

1. Transaction already completed or disposed: If you try to perform an operation after the transaction has already been committed or disposed of, this error will occur.

using (TransactionScope scope = new TransactionScope())
{
    // Perform database operations

    scope.Complete(); // Commit the transaction
}

// Trying to perform an operation after transaction is complete will cause the error
SqlCommand command = new SqlCommand(...);
command.ExecuteNonQuery();

Solutions: