Number missing decimals when inserted in SqlServer table via SqlParameter

Question

I have a database table with two float type columns, and I am trying to insert two numbers via c# code.

This is my code for sql parameters:

sqlCommand.Parameters.Add(new SqlParameter("@Number1", SqlDbType.Decimal) {​​​​ Precision = 17, SqlValue = Number1FloatValue ?? (object)DBNull.Value }​​​​);
sqlCommand.Parameters.Add(new SqlParameter("@Number2", SqlDbType.Decimal) {​​​​ Precision = 17, SqlValue = Number2FloatValue ?? (object)DBNull.Value }​​​​);

First number is -102272.125 and the second is 256.245

In the debugger when I take a look at the values, from some reason SqlValue of the first number becomes -102272.1 - last two digits are missing, and Value property is fine -102272.125, and the second number is ok and gets inserted correctly as 256.245. I thought that it is some problem with the default precision, so I set it to 17, but it didn't helped. And also, firstly I was setting Value instead of SqlValue and later changed to SqlValue assuming that that could be a problem but it didn't helped.

More strangely: when I change SqlDbType.Decimal to SqlDbType.Float (as I tried initially), then first number gets inserted correctly as -102272.125, but the second number gets some unwanted additional decimals: 256.244996832...

I now that float type is not the best way to store decimal numbers in database, but I cannot change the types of table columns.

So, how to get this code insert both values correctly?

This is my code:

static void Main(string[] args)
{
    float? number1 = -102272.125f;
    float? number2 = 256.245f;

    using (SqlConnection openCon = new SqlConnection("Data source=.; Initial Catalog=MyDatabase; Persist Security Info=True; Integrated Security=true;"))
    {
        string saveStaff = "INSERT into test_float (Number1,Number2) VALUES (@Number1,@Number2)";

        using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
        {
            querySaveStaff.Connection = openCon;
            querySaveStaff.Parameters.Add("@Number1", SqlDbType.Float).Value = number1 ?? (object)DBNull.Value;
            querySaveStaff.Parameters.Add("@Number2", SqlDbType.Float).Value = number2 ?? (object)DBNull.Value;
            openCon.Open();

            querySaveStaff.ExecuteNonQuery();
        }
    }
}

And this is databse table and result of an insert. This was my initial problem - Number2 has much more decimals than expected, after which I tried to change SqlDbType to decimal, but running into problem that the first number got rounded to -102272.1, and second number was fine: 256.245. So I am not sure how to get it work in all cases.

And I cannot change the sql table.

When I try something like this:

static void Main(string[] args)
        {
            float? number1 = -102272.125f;
            float? number2 = 256.245f;

            using (SqlConnection openCon = new SqlConnection("Data source=.; Initial Catalog=MyDatabase; Persist Security Info=True; Integrated Security=true;"))
            {
                string saveStaff = "INSERT into test_float (Number1,Number2) VALUES (@Number1,@Number2)";

                using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
                {
                    querySaveStaff.Connection = openCon;
                    //querySaveStaff.Parameters.Add("@Number1", SqlDbType.Float).Value = number1 ?? (object)DBNull.Value;
                    //querySaveStaff.Parameters.Add("@Number2", SqlDbType.Decimal).Value = number2 ?? (object)DBNull.Value;
                    querySaveStaff.Parameters.Add(new SqlParameter("@Number1", SqlDbType.Decimal){Precision = 17, Scale=6, Value = number1, SqlValue = number1});
                    querySaveStaff.Parameters.Add(new SqlParameter("@Number2", SqlDbType.Decimal) { Precision = 17, Scale = 6, Value = number2, SqlValue = number2 });

                    openCon.Open();

                    querySaveStaff.ExecuteNonQuery();
                }
            }
        }

Then, second number is somehow fine, but the first isn't:

Edit 2:

I have just found that using double type in c# for numbers I am trying to insert MAYBE will help:

    double? number1 = -102272.125;
    double? number2 = 256.245;

    using (SqlConnection openCon = new SqlConnection("Data source=.; Initial Catalog=MyDatabase; Persist Security Info=True; Integrated Security=true;"))
    {
        string saveStaff = "INSERT into test_float (Number1,Number2) VALUES (@Number1,@Number2)";

        using (SqlCommand querySaveStaff = new SqlCommand(saveStaff))
        {
            querySaveStaff.Connection = openCon;
            
            querySaveStaff.Parameters.AddWithValue("@Number1", number1 ?? (object)DBNull.Value);
            querySaveStaff.Parameters.AddWithValue("@Number2", number2 ?? (object)DBNull.Value);

            openCon.Open();

            querySaveStaff.ExecuteNonQuery();
        }
    }

Now it looks fine at least for this two numbers: