Insert data from DataGridView to Database using C# in Windows Forms Application

Hi! I using this method for insert data into database it’s not worked. Can anybody help me?

CREATE TABLE [dbo].[TABDOLJ]
(
	[IDDOL] [int] IDENTITY(1,1) NOT NULL,
	[NAMED] [nvarchar](20) NOT NULL,
	[SALARYB] [money] NOT NULL,
	[SALARYS] [money] NOT NULL
)

private void DoljForm_Load(object sender, EventArgs e)
{
    Grid.ColumnCount = 4;
    Grid.Columns[0].Name = "№";
    Grid.Columns[0].Width = 30;
    Grid.Columns[0].HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
    Grid.Columns[1].Name = "Ноигӯи вазифаҳо";
    Grid.Columns[1].Width = 200;
    Grid.Columns[1].HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
    Grid.Columns[2].Name = "Маоши буҷет";
    Grid.Columns[2].Width = 57;
    Grid.Columns[2].HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
    Grid.Columns[3].Name = "Маоши махсус";
    Grid.Columns[3].Width = 57;
    Grid.Columns[3].HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
}

private void btnSave_Click(object sender, EventArgs e)
{
    jobs("del", "", 0, 0);

    foreach (DataGridViewRow row in Grid.Rows)
    {
        jobs("add", row.Cells[1].Value.ToString(), Convert.ToDouble(row.Cells[2].Value), Convert.ToDouble(row.Cells[3].Value));
    }
}
public void jobs(string command, string nm, double bj, double dg)
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Salary"].ConnectionString);
    SqlCommand cmd = con.CreateCommand();
    string sql = "";
    if (command == "add")
    {
        sql = "insert into tabdolj(named, salaryb, salarys)values( " + nm + "," + bj + "," + dg + ")";
    }

    if (command == "del")
    {
        sql = "truncate table tabdolj";
    }

    cmd.CommandText = sql;
    con.Open();
    try
    {
        cmd.ExecuteNonQuery();
    }
    catch { }
    con.Close();
}

Name for example:

Rustam

Suhrob

Asror