How to insert a data table into SQL Server database table?

Create a User-Defined TableType in your database:

CREATE TYPE [dbo].[MyTableType] AS TABLE(
    [Id] int NOT NULL,
    [Name] [nvarchar](128) NULL
)

Create a Table in your database:
CREATE TABLE[dbo].[Records](    [Id] int NOT NULL,
    [Name] [nvarchar](128) NULL
)

and define a parameter in your Stored Ptocedure:

CREATE PROCEDURE [dbo].[InsertTable]
    @myTableType MyTableType readonly
AS
BEGIN
    insert into [dbo].Records 
    select * from @myTableType 
END

and send your DataTable directly to sql server:

protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(getConString());
        using (var command = new SqlCommand("InsertTable") { CommandType = CommandType.StoredProcedure })
        {
            var dt = GetDataTable(); //create your own data table
            command.Parameters.Add(new SqlParameter("@myTableType", dt));            
            command.Connection = con;
            con.Open();
            command.ExecuteNonQuery();
            //SqlHelper.Exec(command);
        }
    }

    private DataTable GetDataTable()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Id");
        dt.Columns.Add("Name");
        dt.Rows.Add("1","Dharmendra");
        dt.Rows.Add("2", "Rakesh" );
        dt.Rows.Add("3", "Mukesh" );
        return dt;
    }