protected override async void OnAppearing() {

        dbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "OrderappDb.db");
        bool DbExists = File.Exists(dbPath);

        var connect = new SqliteConnection("Data Source="   dbPath);
     

    private bool tableExists(SqliteConnection connection, string tableName)
    {
        dbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "OrderappDb.db");
        var connect = new SqliteConnection("Data Source="   dbPath);
        connection = connect;
        try
        {
            if (connection.State == System.Data.ConnectionState.Closed)

                connection.Open();
            using (cmd = new SqliteCommand(connection.ToString()))
            {
                //sqlite_master

                cmd.CommandText = $"Select Count(*) from sqlite_master where type='table' and name='{tableName}';";

                object result = cmd.ExecuteScalar();
                //connection.Open();
                int resultCount = Convert.ToInt32(result);
                if (resultCount > 0)
                    return true;
                connection.Close();
                //  sqlite_master
            }
            return false;
        }

        catch (Exception ex)
        {
            return false;
        }



    }

I am Creating table in sqlite and aceesing that table. Getting ,ExecuteScalar can only be called when the connection is open.Why I Am Getting above error dont understand. Please help with my snippet.

CodePudding user response：

There is not an overload for SqliteCommand how you are using it. You'll want to use

Using SqliteCommand cmd = new SqliteCommand(yourSqlString, connection) {
    Integer val = cmd.executeScalar();
}

https://learn.microsoft.com/en-us/dotnet/api/microsoft.data.sqlite.sqlitecommand?view=msdata-sqlite-7.0.0#constructors

CodePudding user response：

The SqlCommand.ExecuteReader Method Sends the CommandText to the Connection and builds a SqlDataReader. So it need connection.Open(); method to open the connection and this is why the ExecuteScalar method can only be called when the connection open.