[Fixed] ServerVersion' threw an exception of type 'System.InvalidOperationException'

I'm attempting to create a Windows application with a login system. I'm new to Windows programming and encountering an error while trying to connect to a SQL Server Database hosted locally using SSMS 2019, we encountered the error "'ServerVersion' threw an exception of type 'System.InvalidOperationException'" and  error occurs when trying to access the ServerVersion property of a database connection, such as SqlConnection or MySqlConnection, without first opening the connection.

We need to ensure that the database connection is opened before accessing any properties or executing commands.

Here's an example of how to correctly handle the database connection:

    using (var connection = new SqlConnection(connectionString))
    {
        connection.Open(); // Ensure the connection is opened

        // Now we can safely access the properties or execute commands
        Console.WriteLine($"Server version: {connection.ServerVersion}");
    }
  

Please also verify if the password for the SQL Server has not expired. I encountered the same issue due to receiving the error message 'The password of the account has expired.' In such cases, you can resolve this by unchecking the 'Enforce password expiration' option under Login Properties.

By opening the database connection before accessing the ServerVersion property or executing any commands, we can prevent the InvalidOperationException from occurring.

Please check if you connection string and here's a simple example of how to read user data from a database while ensuring the connection is opened:

    using System;
    using System.Data.SqlClient;

    class Program
    {
        static void Main(string[] args)
        {
            string connectionString = "Data Source=DESKTOP-MFLCOI2;Initial Catalog=TestDb;User ID=sa;Password=pass@1234";
            
            using (var connection = new SqlConnection(connectionString))
            {
                connection.Open(); // Ensure the connection is opened

                // Perform SQL query to retrieve user data
                string query = "SELECT * FROM Users";
                SqlCommand command = new SqlCommand(query, connection);
                
                // Execute the command and read the results
                SqlDataReader reader = command.ExecuteReader();
                
                while (reader.Read())
                {
                    // Access user data from each row
                    string username = reader["Username"].ToString();
                    string email = reader["Email"].ToString();
                    
                    // Display user data
                    Console.WriteLine($"Username: {username}, Email: {email}");
                }
                
                // Close the reader and connection
                reader.Close();
            }
        }
    }