C#•3y ago

✅ Using SQLite with C#

The next project of the C# Academy is creating a habit tracker. I'm a little confused on the SQLite aspect of it as I can't seem to get the statement right. I've watched a basic tutorial video https://www.youtube.com/watch?v=oeuTw00F1as&t=725s and I'm using various stack overflows (that make sense) to get my sql working. I have some SQLite knowledge from working with Python, it just seems to be a smidge different.

private static readonly string dbFile = "habits.db";
public static void CreateDatabase()
{
  SQLiteConnection.CreateFile(dbFile);
  var sqlite = new SQLConnection("Data Source=" + dbFile);
  sqlite.Open();
  string sql = @"CREATE TABLE IF NOT EXISTS habits(
                  Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  Name TEXT NOT NULL,
                  TrackType TEXT NOT NULL,
                  Description TEXT NOT NULL
                ";
  SQLiteCommand command = new SQLiteCommand(sql, sqlite);
  command.ExecuteNonQuery();
}
public static void SaveEntry(Habit newHabit)
{
  var slite = new SQLiteConnection("Data Source=" + dbFile);
  sqlite.Open();
  SQLiteCommand insertSQL = new SQLiteCommand(
    "INSERT INTO habits(Name, TrackType, Description) VALUES (?,?,?)",
    sqlite
  );
  insertSQL.Parameters.Add(newHabit.Name);
  insertSQL.Parameters.Add(newHabit.TrackType);
  insertSQL.Parameters.Add(newHabit.Description);

  try
  {
      insertSQL.ExecuteNonQuery();
  }
  catch (Exception ex)
  {
      throw new Exception(ex.Message);
}

private static readonly string dbFile = "habits.db";
public static void CreateDatabase()
{
  SQLiteConnection.CreateFile(dbFile);
  var sqlite = new SQLConnection("Data Source=" + dbFile);
  sqlite.Open();
  string sql = @"CREATE TABLE IF NOT EXISTS habits(
                  Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  Name TEXT NOT NULL,
                  TrackType TEXT NOT NULL,
                  Description TEXT NOT NULL
                ";
  SQLiteCommand command = new SQLiteCommand(sql, sqlite);
  command.ExecuteNonQuery();
}
public static void SaveEntry(Habit newHabit)
{
  var slite = new SQLiteConnection("Data Source=" + dbFile);
  sqlite.Open();
  SQLiteCommand insertSQL = new SQLiteCommand(
    "INSERT INTO habits(Name, TrackType, Description) VALUES (?,?,?)",
    sqlite
  );
  insertSQL.Parameters.Add(newHabit.Name);
  insertSQL.Parameters.Add(newHabit.TrackType);
  insertSQL.Parameters.Add(newHabit.Description);

  try
  {
      insertSQL.ExecuteNonQuery();
  }
  catch (Exception ex)
  {
      throw new Exception(ex.Message);
}

private static readonly string dbFile = "habits.db";
public static void CreateDatabase()
{
  SQLiteConnection.CreateFile(dbFile);
  var sqlite = new SQLConnection("Data Source=" + dbFile);
  sqlite.Open();
  string sql = @"CREATE TABLE IF NOT EXISTS habits(
                  Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  Name TEXT NOT NULL,
                  TrackType TEXT NOT NULL,
                  Description TEXT NOT NULL
                ";
  SQLiteCommand command = new SQLiteCommand(sql, sqlite);
  command.ExecuteNonQuery();
}
public static void SaveEntry(Habit newHabit)
{
  var slite = new SQLiteConnection("Data Source=" + dbFile);
  sqlite.Open();
  SQLiteCommand insertSQL = new SQLiteCommand(
    "INSERT INTO habits(Name, TrackType, Description) VALUES (?,?,?)",
    sqlite
  );
  insertSQL.Parameters.Add(newHabit.Name);
  insertSQL.Parameters.Add(newHabit.TrackType);
  insertSQL.Parameters.Add(newHabit.Description);

  try
  {
      insertSQL.ExecuteNonQuery();
  }
  catch (Exception ex)
  {
      throw new Exception(ex.Message);
}

private static readonly string dbFile = "habits.db";
public static void CreateDatabase()
{
  SQLiteConnection.CreateFile(dbFile);
  var sqlite = new SQLConnection("Data Source=" + dbFile);
  sqlite.Open();
  string sql = @"CREATE TABLE IF NOT EXISTS habits(
                  Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  Name TEXT NOT NULL,
                  TrackType TEXT NOT NULL,
                  Description TEXT NOT NULL
                ";
  SQLiteCommand command = new SQLiteCommand(sql, sqlite);
  command.ExecuteNonQuery();
}
public static void SaveEntry(Habit newHabit)
{
  var slite = new SQLiteConnection("Data Source=" + dbFile);
  sqlite.Open();
  SQLiteCommand insertSQL = new SQLiteCommand(
    "INSERT INTO habits(Name, TrackType, Description) VALUES (?,?,?)",
    sqlite
  );
  insertSQL.Parameters.Add(newHabit.Name);
  insertSQL.Parameters.Add(newHabit.TrackType);
  insertSQL.Parameters.Add(newHabit.Description);

  try
  {
      insertSQL.ExecuteNonQuery();
  }
  catch (Exception ex)
  {
      throw new Exception(ex.Message);
}

I got some of this code from https://stackoverflow.com/questions/19479166/sqlite-simple-insert-query and https://learn.microsoft.com/en-us/dotnet/standard/data/sqlite/?tabs=visual-studio however when I run my code

public class Program
{
    public static void Main(string[] args)
    {
        string filePath = "habits.db";
        if (!File.Exists(filePath))
        {
            Database.CreateDatabase();
        }
        Habit newHabit = new()
        {
            Name = "Test",
            TrackType = "Count",
            Description = "Cigarettes Smoked"
        };
        Database.SaveEntry(newHabit);
     }
}

public class Program
{
    public static void Main(string[] args)
    {
        string filePath = "habits.db";
        if (!File.Exists(filePath))
        {
            Database.CreateDatabase();
        }
        Habit newHabit = new()
        {
            Name = "Test",
            TrackType = "Count",
            Description = "Cigarettes Smoked"
        };
        Database.SaveEntry(newHabit);
     }
}

public class Program
{
    public static void Main(string[] args)
    {
        string filePath = "habits.db";
        if (!File.Exists(filePath))
        {
            Database.CreateDatabase();
        }
        Habit newHabit = new()
        {
            Name = "Test",
            TrackType = "Count",
            Description = "Cigarettes Smoked"
        };
        Database.SaveEntry(newHabit);
     }
}

public class Program
{
    public static void Main(string[] args)
    {
        string filePath = "habits.db";
        if (!File.Exists(filePath))
        {
            Database.CreateDatabase();
        }
        Habit newHabit = new()
        {
            Name = "Test",
            TrackType = "Count",
            Description = "Cigarettes Smoked"
        };
        Database.SaveEntry(newHabit);
     }
}

I get the problem on my

SaveEntry()

SaveEntry()

SaveEntry()

SaveEntry() >

insertSQL.Parameters.Add(newHabit.Name);

insertSQL.Parameters.Add(newHabit.Name);

insertSQL.Parameters.Add(newHabit.Name);

insertSQL.Parameters.Add(newHabit.Name); =>

Unable to cast object of type 'System.String' to type 'System.Data.SQLiteParameter'

Unable to cast object of type 'System.String' to type 'System.Data.SQLiteParameter'

Unable to cast object of type 'System.String' to type 'System.Data.SQLiteParameter'

Unable to cast object of type 'System.String' to type 'System.Data.SQLiteParameter' and I'm not entirely sure why? thanks

✅ Using SQLite with C#

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